U.S. patent application number 12/405445 was filed with the patent office on 2009-07-23 for method of preparing derivatives of polyarylene vinylene and method of preparing an electronic device including same.
This patent application is currently assigned to Interuniversitair Microelektronica Centrum (IMEC). Invention is credited to Kristof Colladet, Anja Henckens, Laurence Lutsen, Dirk Vanderzande.
Application Number | 20090183767 12/405445 |
Document ID | / |
Family ID | 34429660 |
Filed Date | 2009-07-23 |
United States Patent
Application |
20090183767 |
Kind Code |
A1 |
Vanderzande; Dirk ; et
al. |
July 23, 2009 |
METHOD OF PREPARING DERIVATIVES OF POLYARYLENE VINYLENE AND METHOD
OF PREPARING AN ELECTRONIC DEVICE INCLUDING SAME
Abstract
A technique is described for the preparation of polymers
according to a process in which the starting compound of formula
(I) is polymerized in the presence of a base in an organic solvent.
No end chain controlling agents are required during the
polymerisation to obtain soluble precursor polymers. The precursor
polymer such obtained comprises structural units of the formula
(II). In a next step, the precursor polymer (II) is subjected to a
conversion reaction towards a soluble or insoluble conjugated
polymer by thermal treatment. The arylene or heteroarylene polymer
comprises structural units of the formula III. In this process the
dithiocarbamate group acts as a leaving group and permits the
formation of a precursor polymer of structural formula (II), which
has an average molecular weight from 5000 to 1000000 Dalton and is
soluble in common organic solvents. The precursor polymer with
structural units of formula (II) is thermally converted to the
conjugated polymer with structural formula (III). ##STR00001##
Inventors: |
Vanderzande; Dirk; (Hasselt,
BE) ; Lutsen; Laurence; (Coudekerque-Branche, FR)
; Henckens; Anja; (Neerpelt, BE) ; Colladet;
Kristof; (Hasselt, BE) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET, FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
Interuniversitair Microelektronica
Centrum (IMEC)
Leuven
BE
Limburgs Universitair Centrum
Diepenbeek
BE
|
Family ID: |
34429660 |
Appl. No.: |
12/405445 |
Filed: |
March 17, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11779640 |
Jul 18, 2007 |
7511116 |
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12405445 |
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10971784 |
Oct 21, 2004 |
7259228 |
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11779640 |
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Current U.S.
Class: |
136/255 ;
526/256 |
Current CPC
Class: |
H01L 51/0038 20130101;
C08G 61/02 20130101; C08F 128/06 20130101; C08G 61/126 20130101;
C08F 126/06 20130101; Y02E 10/549 20130101; H01L 51/0035 20130101;
Y10S 428/917 20130101; C08F 28/02 20130101; C08G 61/12 20130101;
C08F 228/02 20130101; C08F 290/14 20130101; C08F 28/06
20130101 |
Class at
Publication: |
136/255 ;
526/256 |
International
Class: |
H01L 31/00 20060101
H01L031/00; C08F 28/06 20060101 C08F028/06 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 22, 2003 |
EP |
03447264.7 |
Claims
1. A conjugated polymer with the general formula: ##STR00027##
wherein Ar is an aromatic divalent group or an heteroaromatic
divalent group; wherein each R.sub.3 and R.sub.4 is independently
selected from the group consisting of hydrogen, a C.sub.1-C.sub.20
alkyl group, a cyclic C.sub.3-C.sub.20 alkyl group, an aryl group,
an alkylaryl group, an arylalkyl group and a heterocyclic group;
and wherein n is an integer from 5 to 2000 and which are formed
with the method according to an embodiment.
2. The conjugated polymer of claim 1, wherein Ar comprises from 4
to 20 carbon atoms.
3. The conjugated polymer of claim 1, wherein Ar is substituted
with a substituent selected from the group consisting of
C.sub.1-C.sub.20 alkyl, C.sub.3-C.sub.20 alkoxy, C.sub.1-C.sub.20
alkylsulfate, poly(ethylene oxide), poly(ethylene glycol), phenyl,
and benzyl
4. The conjugated polymer of claim 1, wherein Ar comprises up to
four ring heteroatoms selected from the group consisting of oxygen,
sulphur, and nitrogen.
5. The conjugated polymer of claim 1, wherein Ar is selected from
the group consisting of 2,6-naphthalenediyl, 1,4-naphthalenediyl,
1,4-anthracenediyl, 2,6-anthracenediyl, 9,10-anthracenediyl,
2,4-thienylene, 2,3-thienylene, 2,5-furanediyl, 2,5-pyrrolediyl,
1,3,4-oxadiazole-2,5-diyl, 1,3,4-thiadiazole-2,5-diyl,
2,5-benzo[c]thienylene, thieno[3,2-b]thiophene-2,5-diyl,
pyrrolo[3,2-b]pyrrole-2,5-diyl, pyrene-2,7-diyl,
4,5,9,10-tetrahydropyrene-2,7-diyl, 4,4'-bi-phenylene,
phenantrene-2,7-diyl, 9,10-dihydrophenantrene-2,7-diyl,
dibenzofurane-2,7-diyl, and dibenzothiophene-2,7-diyl.
6. The conjugated polymer of claim 1, wherein Ar is
1,4-phenylene.
7. The conjugated polymer of claim 1, wherein Ar is
2,5-thienylene.
8. The conjugated polymer of claim 1, having a formula:
##STR00028## wherein the conjugated polymer has a peak at a
wavelength higher than 520 nm in the absorption spectrum.
9. The conjugated polymer of claim 1, wherein the conjugated
polymer has a peak at a wavelength of 570 nm in the absorption
spectrum.
10. The conjugated polymer of claim 1, having an average molecular
weight of from 5000 daltons to 1000000 daltons.
11. The conjugated polymer of claim 1, having an average molecular
weight of from 5000 daltons to 500000 daltons.
12. The conjugated polymer of claim 1, wherein a polydispersity of
the conjugated polymer is from 1.5 to 5.5.
13. The conjugated polymer of claim 1, wherein a polydispersity of
the conjugated polymer is from 2 to 3.
14. The conjugated polymer of claim 1, wherein the conjugated
polymer is a linear polymer.
15. The conjugated polymer of claim 1, wherein the conjugated
polymer is fully converted.
16. The conjugated polymer of claim 1, comprising at least two
different monomers having a general formula: ##STR00029##
17. The conjugated polymer of claim 1, comprising no chain end
controlling additive.
18. A device selected from the group consisting of a solar cell, a
light-emitting diode and an integrated circuit, an organic
transistor, a chemical sensor, and a biological sensor, wherein the
device comprises a layer of a conjugated polymer of claim 1.
19. The device of claim 18, wherein Ar is selected from the group
consisting of 1,4-phenylene and 2,5-thienylene, and wherein R.sub.3
and R.sub.4 are hydrogen.
20. The device of claim 18, wherein the device is a solar cell, and
wherein an active layer of the device comprises the conjugated
polymer.
21. The device of claim 18, wherein the device is an organic bulk
heterojunction solar cell, and wherein an active layer of the
device comprises a blend of an n-type material and the conjugated
polymer.
22. The device of claim 21, wherein the n-type material is a
C.sub.60 derivative.
23. The device of claim 18, further comprising an electrode atop
the layer of conjugated polymer.
24. The device of claim 18, wherein the layer of conjugated polymer
is an annealed layer wherein stresses in the polymer chains are
reduced.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 11/779,640 filed Jul. 18, 2007, which is a division of U.S.
application Ser. No. 10/971,784 filed Oct. 21, 2004, which claims
the benefit under 35 U.S.C. .sctn. 119(a)-(d) of European
application No. 03447264.7 filed Oct. 22, 2003, the disclosures of
which are hereby expressly incorporated by reference in their
entirety and are hereby expressly made a portion of this
application.
FIELD OF THE INVENTION
[0002] The present invention relates to a method for the
preparation of soluble precursor polymers of arylene and
heteroarylene vinylene polymers and their conversion towards
arylene and heteroarylene vinylene polymers, and to devices
including the same.
BACKGROUND OF THE INVENTION
[0003] Conjugated polymers are of great interest for the
development of optical and electronic applications. The most
investigated conjugated polymers are poly(thiophene) (PT) and
poly(p-phenylene vinylene) (PPV). Also poly(2,5-thienylene
vinylene) (PTV) has attracted great attention because of its high
electrical conductivity upon doping and its possible application as
a semiconductor in all-polymer field effect transistors.
Additionally, PTV is a low band gap semiconductor polymer, which
makes it a very interesting material for organic photovoltaic
devices.
[0004] Several methods have been developed to synthesize PTV. In
the early days, PTV was synthesised via the Wessling polymerisation
method, which is described in U.S. Pat. No. 3,401,152 by R. A.
Wessling and R. G. Zimmerman and in J. Polym. Sci.: Polym. Symp.
1985, 72, 55 by R. A. Wessling. The polymerization reaction
according to the Wessling method is difficult, because the products
tend to form a gel. Moreover, strong acids, which could be toxic,
are required during the conversion reaction.
[0005] In 1987, Murase et al. and Yamada et al. reported the
synthesis of PTV via a precursor polymer with methoxy leaving
groups (I. Murase, T. Ohnishi, T. Noguchi, M. Hirooka, Polym.
Commun. 1987, 28, 229; S. Yamada, S. Tokito, T. Tsutsui, S. Saito,
J. Chem. Soc., Chem. Commun. 1987, 1448). This reaction is an acid
catalysed conversion reaction, which is incompatible with device
fabrication.
[0006] In 1990, Elsenbaumer et al. reported the synthesis and
characterisation of PTV and some alkyl-substituted PTV's (R. L.
Elsenbaumer, Mol. Cryst. Liq. Cryst 1990, 186, 211). These methods
are far from ideal especially for the PTV derivatives due to the
relative high reactivity of the monomer and precursor polymer which
complicates both monomer and polymer synthesis. The high reactivity
is originated from the high electron density of the thiophene ring,
which induces a very high instability of the starting monomer when
this monomer is reached but generally with low reproducibility and
very low yields due to many side-reactions.
[0007] This is also the reason why problems occur by using the more
recent precursor methods like the sulfinyl route, developed by
Vanderzande et al. in 1997 (A. J. J. M. Van Breemen, A. C. J.
Issaris, M. M. de Kok, M. J. A. N. Van Der Borght, P. J.
Adriaensens, J. M. J. V. Gelan, D. J. M. Vanderzande,
Macromolecules 1999, 32, (18), 5728), the bis-xanthate route
developed by Son in 1995 and Burn et al. in 2001 and described in
(1997 U.S. Pat. No. 5,621,069; European patent EP 0 707 022 A2;
S--C. Lo, L.-O. Palsson, M. Kilitziraki, P. L. Burn, I. D. W.
Samuel, J. Mater. Chem. 2001, 11, 2228) and the bis-sulfide route
developed by Herwig et al in 2003 (US patent 2003/0027963 A1).
[0008] To use PTV, other poly(arylene vinylene)s and
poly(heteroarylene vinylene) derivatives in plastic electronics, an
easy accessible precursor polymer that can be manufactured on a
large scale is desirable.
SUMMARY OF THE INVENTION
[0009] It is an object to provide a method for the synthesis of
soluble or insoluble conjugated polymers like arylene of
heteroarylene vinylene, optionally in good yields, optionally with
high molecular weight, optionally good quality, e.g. low defect
level and optionally in large scale. It is a further aim to
describe the use of these soluble or insoluble conjugated polymers
for organic solar cells, organic transistors and other kinds of
electronic devices.
[0010] It is a further aim to describe a novel precursor polymer,
to be used as intermediate compound in the synthesis of arylene of
heteroarylene vinylene polymers.
[0011] In a first aspect, a method for the preparation of a
precursor polymer is disclosed. The precursor polymer has the
general formula
##STR00002##
wherein Ar is an aromatic divalent group or a heteroaromatic
divalent group, wherein R.sub.0 is an organic group selected from
the group consisting of an amine --NR.sub.1R.sub.2, a
C.sub.5-C.sub.20 alkyloxy group, an aryloxy group, an alkyl group,
an aryl group, an alkylaryl group, an arylalkyl group, a thioether
group, an ester group, an acid carboxylic group, and a heterocyclic
group, and wherein R.sub.3 and R.sub.4 are independently from each
other hydrogen or an organic group selected from the group
consisting of a C.sub.1-C.sub.20-alkyl group, a cyclic
C.sub.3-C.sub.20-alkyl group, an aryl group, an alkylaryl group, an
arylalkyl group, a thioether group, an ester group, an acid
carboxylic group and a heterocyclic group, and wherein n is the
number of repeating units.
[0012] In a specific embodiment, the precursor polymer may have the
formula as formula (II) wherein R.sub.0 is an amine
--NR.sub.1R.sub.2
##STR00003##
and in which R.sub.1 and R.sub.2 are independently from each other
an organic group selected from the group consisting of a
C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.3-C.sub.20-alkyl
group, an aryl group, an alkylaryl group, an arylalkyl group and a
heterocyclic group, R.sub.1 and R.sub.2 may be linked together to
form a cycle. One typical example of such a precursor polymer may
be a precursor polymer wherein R.sub.0=--NR.sub.1R.sub.2 and
wherein R.sub.1=R.sub.2=Et:
##STR00004##
[0013] In other specific examples of precursor polymers which may
be used in embodiments, R.sub.0 may be a phenyl group, a methyl
group or a group (F.sub.6C.sub.6O):
##STR00005##
[0014] In further specific examples, precursor polymers may be used
which are based on poly(p-phenylene vinylene) derivatives, such as
for example alkoxy poly(p-phenylene vinylene) (alkoxy-PPV)
derivatives such as e.g. precursor polymers based on
poly(2-methoxy, 5-3',7'-dimethyloctyloxy)-1,4-phenylene vinylene
(MDMO-PPV or OC.sub.1C.sub.10PPV), or based on poly(p-thienylene
vinylene) (PTV) derivatives.
[0015] A method comprises the steps of: [0016] providing a monomer
having the general formula
##STR00006##
[0016] wherein Ar is an aromatic divalent group or a heteroaromatic
divalent group, wherein R.sub.0 is an organic group selected from
the group consisting of an amine --NR.sub.1R.sub.2, a
C.sub.5-C.sub.20 alkyloxy group, an aryloxy group, an alkyl group,
an aryl group, an alkylaryl group, an arylalkyl group, a thioether
group, an ester group, an acid carboxylic group, and a heterocyclic
group, and [0017] reacting said monomer with a basic compound in
the presence of an organic solvent to obtain said precursor
polymer, hereby not requiring the use of a chain end controlling
additive.
[0018] In a specific embodiment, a monomer may be provided, having
the formula according to formula (I), wherein R.sub.0 is an amine
--NR.sub.1R.sub.2, in which R.sub.1 and R.sub.2 are independently
from each other an organic group selected from the group consisting
of a C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.3-C.sub.20-alkyl
group, an aryl group, an alkylaryl group, an arylalkyl group and a
heterocyclic group, R.sub.1 and R.sub.2 may be linked together to
form a cycle.
[0019] The basic compound may be selected from the group consisting
of a metal oxide, a metal alkoxide, a metal amide, organometal
compounds, grignard reagents and ammonium hydroxide. The amount of
basic compound may be between 1 and 2 equivalents with respect to
the monomer.
[0020] The concentration of the monomer used in the method may be
between 0.1 and 0.3 M.
[0021] In an embodiment of the first aspect, the Ar group may be an
aromatic divalent group with 4 to 20 carbon atoms which may be
substituted with one or more substituents independently selected
from the group consisting of C.sub.1-C.sub.20-alkyl,
C.sub.3-C.sub.20-alkoxy or C.sub.1-C.sub.20-alkylsulfate,
poly(ethylene oxide) (PEO) or oligo(ethylene oxide), poly(ethylene
glycol) (PEG) or oligo(ethylene glycol). These aromatic divalent
groups may comprise up to 4 heteroatoms chosen from the group
comprising oxygen, sulphur, and nitrogen.
[0022] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,5-furanediyl; 2,5-pyrrolediyl;
1,3,4-oxadiazole-2,5-diyl; 1,3,4-thiadiazole-2,5-diyl;
2,5-benzo[c]thienylene; thieno[3,2-b]thiophene-2,5-diyl;
pyrrolo[3,2-b]pyrrole-2,5-diyl; pyrene-2,7-diyl;
4,5,9,10-tetrahydropyrene-2,7-diyl; 4,4'-bi-phenylene;
phenantrene-2,7-diyl; 9,10-dihydrophenantrene-2,7-diyl;
dibenzofurane-2,7-diyl; dibenzothiophene-2,7-diyl. Preferably, Ar
is 1,4-phenylene or 2,5-thienylene and most preferably Ar is
2,5-thienylene.
[0023] In a preferred embodiment, R.sub.1 and R.sub.2 may be a
C.sub.1-C.sub.20-alkyl group. In another embodiment, R.sub.1 and
R.sub.2 may be selected from the group consisting of methyl, ethyl
and isopropyl.
[0024] In a further embodiment of the first aspect, reacting the
monomer with a basic compound may be performed at a temperature
between -78.degree. C. and 200.degree. C., preferably between
-40.degree. C. and 120.degree. C., and most preferably between
-20.degree. C. and 30.degree. C. The temperature may be selected
such that the average molecular weight of the soluble precursor
polymer is as high as possible and that the polydispersity is as
low as possible.
[0025] The method as described in the first aspect may require
symmetrical starting monomers. Symmetrical starting molecules have
the advantage that they are easier to synthesise than asymmetric
starting monomers. Furthermore, symmetrical starting monomers with
dithiocarbamate groups are stable in time. The polymerisation of
the symmetrical monomer in a solvent and in the presence of a base
may lead to a precursor polymer soluble in common organic solvents.
Those solvents may be polar, apolar and mixtures thereof. The
solvent may for example be an aprotic solvent. The dithiocarbamate
groups act as a leaving group and as a polarizer during the
polymerisation.
[0026] Furthermore, an embodiment provides a precursor polymer with
the formula:
##STR00007##
wherein Ar is an aromatic divalent group or heteroaromatic divalent
group, wherein R.sub.0 is an organic group selected from the group
consisting of an amine --NR.sub.1R.sub.2, a C.sub.5-C.sub.20
alkyloxy group, an aryloxy group, an alkyl group, an aryl group, an
alkylaryl group, an arylalkyl group, a thioether group, an ester
group, an acid carboxylic group or a heterocyclic group. The
C.sub.1-C.sub.20-alkyl group, cyclic C.sub.4-C.sub.20-alkyl group,
phenyl group and benzyl group may comprise heteroatoms and
substituents. In a preferred embodiment, R.sub.1 and R.sub.2 may
independently be selected from methyl, ethyl or propyl. R.sub.3 and
R.sub.4 are chosen from the group comprising a hydrogen atom and a
C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.4-C.sub.20-alkyl
group, a phenyl group and a benzyl group, which groups may comprise
heteroatoms and substituents. In a preferred embodiment, R.sub.3
and R.sub.4 may be hydrogen. All possible combinations of Ar,
R.sub.0, R.sub.1, R.sub.2, R.sub.3 en R.sub.4 may be included in
this invention.
[0027] In a specific embodiment, the precursor polymer may have the
formula as formula (II) wherein R.sub.0 is an amine
--NR.sub.1R.sub.2:
##STR00008##
and in which R.sub.1 and R.sub.2 are independently from each other
an organic group selected from the group consisting of a
C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.3-C.sub.20-alkyl
group, an aryl group, an alkylaryl group, an arylalkyl group and a
heterocyclic group, R.sub.1 and R.sub.2 may be linked together to
form a cycle. One typical example of such a precursor polymer may
be a precursor polymer wherein R.sub.0=--NR.sub.1R.sub.2 and
wherein R.sub.1=R.sub.2=Et:
##STR00009##
[0028] In other specific examples of precursor polymers which may
be used in embodiments, R.sub.0 may be a phenyl group, a methyl
group or a group (F.sub.6C.sub.6O):
##STR00010##
[0029] In other specific examples, precursor polymers may be based
on poly(p-H phenylene vinylene) derivatives, such as for example
alkoxy poly(p-phenylene vinylene) (alkoxy-PPV) derivatives such as
e.g. poly(2-methoxy, 5-3',7'-dimethyloctyloxy)-1,4-phenylene
vinylene (MDMO-PPV or OC.sub.1C.sub.10PPV), or on poly(p-thienylene
vinylene) derivatives.
[0030] In a preferred embodiment, the Ar group may comprise 4 to 20
carbon atoms. In another embodiment, the Ar groups may be
substituted with a substituent chosen from the group consisting of
a C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-alkoxy,
C.sub.1-C.sub.20-alkylsulfate, poly(ethylene oxide) (PEO) or
oligo(ethylene oxide), poly(ethylene glycol) (PEG) or
oligo(ethylene glycol), a phenyl or a benzyl group and these Ar
groups may comprise up to 4 heteroatoms chosen from the group
comprising oxygen, sulphur, and nitrogen in the aromatic cyclic
system. In other embodiments, the substituents may be linear, or
cyclic or two substituents may be linked together to form a cycle
on the Ar groups. In still a further embodiment, the substituents
may contain charges, ions, cations or anions.
[0031] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
[0032] The precursor polymers may show high molecular weight,
between 5000 and 500000, more particularly between 7000 and 250000,
especially between 7500 and 100000 Dalton. Furthermore, the
polydispersity of the precursor polymers may be between 1.5 and
5.5, preferably below 2. The precursor polymer may be obtained in
good overall yields in a reproducible way. Large-scale production
may be a possibility.
[0033] In a second aspect a method for the preparation of soluble
or insoluble conjugated arylene and heteroarylene vinylene polymers
is disclosed. The method does not require the use of chain end
controlling additives. The soluble or insoluble conjugated arylene
heteroarylene vinylene polymers have the general formula:
##STR00011##
wherein Ar is equal to the Ar group in the first aspect.
[0034] The method comprises the steps of:
[0035] providing at least one precursor polymer having the general
formula
##STR00012##
wherein Ar is an aromatic divalent group or an heteroaromatic
divalent group, wherein R.sub.0 is an organic group selected from
the group consisting of an amine --NR.sub.1R.sub.2, a
C.sub.5-C.sub.20 alkyloxy group, an aryloxy group, an alkyl group,
an aryl group, an alkylaryl group, an arylalkyl group, a thioether
group, an ester group, an acid carboxylic group, and a heterocyclic
group, and wherein R.sub.3 and R.sub.4 are independently from each
other hydrogen or an organic group selected from the group
consisting of a C.sub.1-C.sub.20-alkyl group, a cyclic
C.sub.3-C.sub.20-alkyl group, an aryl group, an alkylaryl group, an
arylalkyl group, a thioether group, an ester group, an acid
carboxylic group and a heterocyclic group, wherein n is the number
of repeating units, and [0036] subjecting the precursor polymer to
a thermal conversion reaction which comprises total or partial
elimination of the --SC(S)R.sub.0 groups by thermal treatment at a
temperature between 30.degree. C. and 300.degree. C. in solution or
in thin film.
[0037] In a specific example, a precursor polymer is provided with
formula as formula (II) wherein R.sub.0 is an amine
--NR.sub.1R.sub.2:
##STR00013##
and in which R.sub.1 and R.sub.2 are independently from each other
an organic group selected from the group consisting of a
C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.3-C.sub.20-alkyl
group, an aryl group, an alkylaryl group, an arylalkyl group and a
heterocyclic group, R.sub.1 and R.sub.2 may be linked together to
form a cycle. One typical example of such a precursor polymer may
be a precursor polymer wherein R.sub.0=--NR.sub.1R.sub.2 and
wherein R.sub.1=R.sub.2=Et.
##STR00014##
[0038] In other specific examples of precursor polymers which may
be used in embodiments according to the invention, Ro may be a
phenyl group, a methyl group or a group (F.sub.6C.sub.6O):
##STR00015##
[0039] In other specific examples, precursor polymers may be used
which are based on poly(p-phenylene vinylene) derivatives, such as
for example alkoxy poly(p-phenylene vinylene) (alkoxy-PPV)
derivatives such as e.g. poly(2-methoxy,
5-3',7'-dimethyloctyloxy)-1,4-phenylene vinylene (MDMO-PPV or
OC.sub.1C.sub.10PPV), or on poly(p-thienylene vinylene)
derivatives.
[0040] The precursor polymer may be synthesized according to the
method described in the first aspect. In one embodiment of the
second aspect, the duration of the subjecting step may be lower
than 24 hours, lower than 8 hours and preferably lower than 3
hours.
[0041] In an embodiment of the first aspect, the Ar group may be an
aromatic divalent group with 4 to 20 carbon atoms which may be
substituted with one or more substituents independently selected
from the group consisting of C.sub.1-C.sub.20-alkyl,
C.sub.3-C.sub.20-alkoxy, C.sub.1-C.sub.20-alkylsulfate,
poly(ethylene oxide) (PEO), poly(ethylene glycol) (PEG), a phenyl
group or a benzyl group. These Ar groups may comprise up to 4
heteroatoms chosen from the group comprising oxygen, sulphur, and
nitrogen in the aromatic divalent group. Furthermore, these groups
may independently be linear, or cyclic or two of these groups may
be linked together to form a cycle on the Ar group.
[0042] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4 thienylene; 2,3 thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar is 1,4-phenylene or
2,5-thienylene and most preferably Ar is 2,5-thienylene.
[0043] The conjugated arylene or heteroarylene vinylene polymers
may be obtained by thermal conversion of the precursor polymer in
which the remaining dithiocarbamate group acts as a leaving group
(or evaporating group). The conjugated polymer may show a low
structural defect level.
[0044] In a preferred embodiment, R.sub.1 and R.sub.2 may be a
C.sub.1-C.sub.20-alkyl group. In another embodiment, R.sub.1 and
R.sub.2 may be selected from the group consisting of methyl, ethyl
or propyl.
[0045] In a preferred embodiment, R.sub.1 and R.sub.2 may be a
C.sub.1-C.sub.20-alkyl. In another embodiment, R.sub.1 and R.sub.2
may be selected from the group consisting of methyl, ethyl, propyl
or phenyl. In another preferred embodiment, R.sub.3 and R.sub.4 may
be hydrogen.
[0046] In a preferred embodiment, said conjugated arylene vinylene
polymer is poly (2,5 thienylene vinylene) and its derivatives.
[0047] In a further embodiment of the second aspect the precursor
polymer may be dissolved in an organic or non-organic solvent and
the conversion reaction or elimination reaction may be performed in
solution by thermal treatment under inert or controlled atmosphere
to lead to a soluble or insoluble conjugated polymer. This method
may in generally be used when the conjugated polymer is expected to
be soluble in organic and/or non-organic solvents. In a further
embodiment according this second aspect the precursor polymer may
be in the form of a thin film precursor polymer layer and the
conversion or elimination reaction step may be performed under
inert or controlled atmosphere or under vacuum by in situ thermal
treatment.
[0048] In a further embodiment of the second aspect, the precursor
polymer may be dissolved in a solvent, followed by a degassing
step.
[0049] In a further embodiment of the second aspect, the thermal
conversion step may be performed at a temperature between
30.degree. C. and 300.degree. C., preferably between 80.degree. C.
and 300.degree. C., and most preferably between 115.degree. C. and
250.degree. C.
[0050] In a further embodiment of the second aspect the yield of
the method may be between 30% and 90%.
[0051] Compared to the Wessling route, the method has the advantage
of leading to polymerisation without gel formation and requiring no
toxic gas (like strong acids) during the conversion reaction.
[0052] Compared to the Gilch route, an embodiment has the
advantages of leading to polymers that can also be insoluble in
their conjugated form. The Gilch route is a one-pot polymerisation,
which only allows the synthesis of soluble conjugated polymers; it
is not a precursor route as is the case in this embodiment.
[0053] Compared to the sulfinyl route, an embodiment has the
advantages of leading to stable monomers.
[0054] Compared to the Hsieh method (U.S. Pat. No. 5,817,430), the
method does not require the use of chain end controlling additives
to control the molecular weight in order to get soluble conjugated
polymers. Contrary to the Hsieh method, which is a side chain
approach, the method according to an embodiment is a "precursor
method" which does not require control of the molecular weight. The
resulting precursor polymers are always soluble polymers, whatever
their molecular weight is and are soluble even for very high
molecular weight. The related conjugated polymer may be obtained in
a second step by a conversion or elimination reaction under thermal
treatment to lead to soluble or insoluble conjugated polymers. When
the conjugated polymer is expected to be insoluble, the elimination
reaction may preferably be carried out in thin film. When the
conjugated polymer is expected to be soluble, the elimination
reaction may be carried out either in solution or in thin film.
[0055] Precursor polymers synthesised from a monomer having a
symmetrical structure may be much easier to synthesise and to
obtain in good yield. No complicated purification step by
chromatography column of the monomer is requested.
[0056] Precursor polymers with leaving groups (e.g.
dithiocarbamate) are compatible with a device application. The
lifetime of the device is not influenced by remaining traces of
leaving groups in the active layer after the conversion
reaction.
[0057] During the conversion step, the leaving groups of the
precursor polymers are eliminated and double bonds of the
conjugated polymer are formed. In one embodiment, substantially all
of the leaving groups are eliminated, thus forming a fully
converted conjugated polymer. However, in another embodiment, only
between 90 and 100% of the leaving groups may be eliminated. Hence,
between 0 and 10% of the leaving groups is still present in the
resulting conjugated polymer. Thus, the resulting polymer is only
partially converted. This polymer will be referred to as partially
converted conjugated polymer. The amount of remaining leaving
groups in the partially converted conjugated polymer may be
controlled by changing the experimental circumstances of the
conversion reaction.
[0058] Compared to the bis-sulfide route (EP 1 290 059 A1), the
method has the advantage of leading to polymers by means of
polymerisation of monomers which are much more stable and therefore
allow the synthesis of polymers for which the instability of the
monomers can be a problem to obtain such polymer in a reliable way.
In the bis-sulfide route, over-oxidation can occur easily as the
oxidation of the sulfide groups is carried out after polymerisation
and not on the starting monomer. Structural defects have a negative
effect on the charge mobility of conjugated polymers
[0059] Compared to the bis-xanthate route, an embodiment has the
advantages of leading to: [0060] monomers and soluble precursor
polymers stable in time in inert atmosphere. [0061] precursors and
conjugated polymers with a much lower polydispersity around 2 to 3
(while being between 20 and 30 for the xanthate-route). [0062]
reproducibility between batches. [0063] precursor polymers obtained
through polymerisation reaction carried out at a temperature
ranging from -78.degree. C. to 30.degree. C. [0064] the yield of
the polymerisation reaction is higher than 50%. [0065] conjugated
polymers with low defect level. [0066] polymers with an increase of
.lamda..sub.max of about 20 nm for a PTV derivative at room
temperature synthesised according to an embodiment, compared to the
same PTV derivative synthesised via another method. For example,
poly(2,5-thienylene vinylene), having no substituent on Ar, has a
.lamda..sub.max value around 545 nm for PTV at high temperature and
570 nm at room temperature when synthesised according to the method
of an embodiment compared to the same poly(2,5-thienylene vinylene)
having no substituents on Ar which has a .lamda..sub.max value
around 500-520 nm at high temperature when synthesised via the
xanthate-route and the .lamda..sub.max value may be varied from
batch to batch. [0067] large-scale synthesis is possible.
[0068] Furthermore, an embodiment provides a conjugated arylene or
heteroarylene vinylene polymer with the general formula:
##STR00016##
wherein Ar is an aromatic group or an heteroaromatic divalent
group, wherein R.sub.3 and R.sub.4 are independently from each
other hydrogen or an organic group selected from the group
consisting of a C.sub.1-C.sub.20-alkyl group, a cyclic
C.sub.3-C.sub.20-alkyl group, an aryl group, an alkylaryl group, an
arylalkyl group and a heterocyclic group, and wherein n is an
integer from 5 to 2000 and which are formed with the method
according to an embodiment.
[0069] In a preferred embodiment, Ar comprises 4 to 20 carbon
atoms. In another embodiment, the Ar groups may be substituted with
a substituent chosen from the group consisting of a
C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-alkoxy,
C.sub.1-C.sub.20-alkylsulfate, poly(ethylene oxide) (PEO),
poly(ethylene glycol) (PEG), a phenyl or a benzyl group and the Ar
groups may comprise up to 4 heteroatoms chosen from the group
comprising oxygen, sulphur, and nitrogen in the aromatic cyclic
system.
[0070] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
[0071] All possible combination of Ar, R.sub.0, R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 are included in this invention.
[0072] The conjugated polymers, prepared according to a method
described in the previous embodiments has less defects with respect
to the prior art.
[0073] In a specific, preferred embodiment, the conjugated arylene
or heteroarylene vinylene polymer is a poly(2,5-thienylene
vinylene) or PTV polymer with formula:
##STR00017##
[0074] Due to the fact that the polymer is prepared by the method
as described herein, the poly(2,5-thienylene vinylene) polymer
shows a peak at a wavelength higher than 520 nm in the absorption
spectrum.
[0075] In another embodiment, also other PTV derivatives, which
have side chains on the 2 and 3 positions (instead of on the 2 and
5 positions in the previous embodiment) on the thiophene ring may
be used.
[0076] In a preferred embodiment, the polymer may be characterized
by a peak at a wavelength higher than 540 nm in the absorption
spectrum.
[0077] The average molecular weight of the polymer may be between
5000 daltons and 500000 daltons, whereas the polydispersity may be
between 1.5 and 5.5. Furthermore, the polymer may be a linear
polymer.
[0078] The method according to an embodiment does not require the
use of a chain end controlling additive.
[0079] In an embodiment at least two monomers having formula (I)
may be polymerised together to form a copolymer.
[0080] In a third aspect, an electronic device is provided. The
electronic device comprises a thin layer of conjugated polymer
synthesised according to an embodiment and having the formula
(III). Ar, R.sub.3 and R.sub.4 are equal to Ar, R.sub.3 and R.sub.4
as described in the first and the second aspect. The electronic
device according to the third aspect has several advantages. The
polymers were found to have less defects. As a result, the polymer
has better properties, resulting in a better electronic device.
[0081] In a first embodiment of the third aspect, the device may be
a light-emitting diode. The light-emitting diode may comprise
polymers having structural units of formula (III). Preferably, Ar
may be 1,4-phenylene or 2,5-thienylene while R.sub.3 and R.sub.4
may be hydrogen.
[0082] In a further embodiment, the device may be a circuit or
organic transistor. The integrated circuit may comprise polymers
having structural units of formula (III), wherein Ar preferably may
be 1,4-phenylene or 2,5-thienylene while R.sub.3 and R.sub.4 may be
hydrogen. Such integrated circuits have the advantage of having a
lower cost price. According to an embodiment, the device may also
be a chemical sensor or a biological sensor
[0083] The invention further relates to a method of manufacturing a
layer of a polymer with structural units having the formula (II) or
(III).
[0084] An embodiment further relates to a method of manufacturing
bilayer heterojunction organic solar cells using a soluble
precursor polymer containing structural units of formula (II). The
active layer made from the soluble precursor polymer may become
effectively active only after conversion reaction towards the
related soluble or insoluble conjugated polymer by an elimination
reaction under heat treatment in situ in thin film.
[0085] Furthermore, an embodiment relates to a method of
manufacturing organic bulk heterojunction solar cells using as an
active layer a blend of an n-type material, such as a soluble
C.sub.60 derivatives, and a p-type material, such as a precursor
polymer containing structural units of formula (II). The active
layer made from the n-type/p-type material blend may become an
active layer only after the conversion reaction of the thin film by
heat treatment.
[0086] The invention further relates to a method of manufacturing
organic transistors using a polymer containing structural units of
formula (II). The active layer made from the soluble precursor
polymer may become effectively active after conversion reaction
towards the soluble or insoluble conjugated polymer by elimination
reaction of the leaving groups and formation of the vinylene double
bonds by heat treatment.
[0087] In a fourth aspect, a method for manufacturing an electronic
device is disclosed. The electronic device comprises a polymer
layer. In the method according to an embodiment, a layer comprising
the soluble precursor polymer (II) is deposited. In a next step,
the conjugated polymer (III) layer is obtained by carrying out the
conversion reaction of the coated soluble precursor polymer layer
towards the active soluble or insoluble conjugated polymer by
elimination of the leaving groups and formation of the vinylene
doubled bonds induced by heat treatment.
[0088] On the active soluble or insoluble conjugated polymer layer
a further annealing treatment may be carried out in order to remove
stresses of the polymer chains introduced during the deposition of
the thin film layer and in order to induce a relaxation of the
polymer chains and changes in the polymer film morphology. This
annealing may be carried out before or after the electrode
deposition on top of the active conjugated polymer layer.
[0089] These and other characteristics, features and advantages of
the present invention will become apparent from the following
detailed description.
DEFINITIONS
[0090] As used herein with respect to a substituting radical, and
unless otherwise stated, the terms "C.sub.1-7 alkyl" or "aliphatic
saturated hydrocarbon radicals with 1 to 7 carbon atoms" means
straight and branched chain saturated acyclic hydrocarbon
monovalent radicals having from 1 to 7 carbon atoms such as, for
example, methyl, ethyl, propyl, n-butyl, 1-methylethyl (isopropyl),
2-methylpropyl (isobutyl), 1,1-dimethylethyl (ter-butyl),
2-methyl-butyl, n-pentyl, dimethylpropyl, n-hexyl, 2-methylpentyl,
3-methylpentyl, n-heptyl and the like; the term "C.sub.1-4 alkyl"
designate the corresponding radicals with only 1 to 4 carbon atoms,
and so on.
[0091] As used herein with respect to a substituting radical, and
unless otherwise stated, the term "C.sub.1-7 alkylene" means the
divalent hydrocarbon radical corresponding to the above defined
C.sub.1-7 alkyl, such as methylene, bis(methylene),
tris(methylene), tetramethylene, hexamethylene and the like.
[0092] As used herein with respect to a substituting radical, and
unless otherwise stated, the terms "C.sub.3-10 cycloalkyl" and
"cycloaliphatic saturated hydrocarbon radical with 3 to 10 carbon
atoms" mean a mono- or polycyclic saturated hydrocarbon monovalent
radical having from 3 to 10 carbon atoms, such as for instance
cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,
cyclooctyl and the like, or a C.sub.7-10 polycyclic saturated
hydrocarbon monovalent radical having from 7 to 10 carbon atoms
such as, for instance, norbornyl, fenchyl, trimethyltricycloheptyl
or adamantyl.
[0093] As used herein with respect to a substituting radical, and
unless otherwise stated, the terms "aryl" and "aromatic
substituent" are interchangeable and designate any mono- or
polycyclic aromatic monovalent hydrocarbon radical having from 6 up
to 30 carbon atoms such as but not limited to phenyl, naphthyl,
anthracenyl, phenantracyl, fluoranthenyl, chrysenyl, pyrenyl,
biphenylyl, terphenyl, picenyl, indenyl, biphenyl, indacenyl,
benzocyclobutenyl, benzocyclooctenyl and the like, including fused
benzo-C.sub.4-8 cycloalkyl radicals (the latter being as defined
above) such as, for instance, indanyl, tetrahydronaphtyl, fluorenyl
and the like, all of the said radicals being optionally substituted
with one or more substituents selected from the group consisting of
halogen, amino, nitro, hydroxyl, sulfhydryl and nitro, such as for
instance 4-fluorophenyl, 4-chlorophenyl, 3,4-dichlorophenyl,
4-cyanophenyl.
[0094] As used herein with respect to a substituting radical
(including the combination of two substituting radicals), and
unless otherwise stated, the term "heterocyclic" means a mono- or
polycyclic, saturated or mono-unsaturated or polyunsaturated
monovalent hydrocarbon radical having from 2 up to 15 carbon atoms
and including one or more heteroatoms in one or more heterocyclic
rings, each of said rings having from 3 to 10 atoms (and optionally
further including one or more heteroatoms attached to one or more
carbon atoms of said ring, for instance in the form of a carbonyl
or thiocarbonyl or selenocarbonyl group, and/or to one or more
heteroatoms of said ring, for instance in the form of a sulfone,
sulfoxide, N-oxide, phosphate, phosphonate or selenium oxide
group), each of said heteroatoms being independently selected from
the group consisting of nitrogen, oxygen, sulfur, selenium and
phosphorus, also including radicals wherein a heterocyclic ring is
fused to one or more aromatic hydrocarbon rings for instance in the
form of benzo-fused, dibenzo-fused and naphto-fused heterocyclic
radicals; within this definition are included heterocyclic radicals
such as, but not limited to, diazepinyl, oxadiazinyl, thiadiazinyl,
dithiazinyl, triazolonyl, diazepinonyl, triazepinyl, triazepinonyl,
tetrazepinonyl, benzoquinolinyl, benzothiazinyl, benzothiazinonyl,
benzoxathiinyl, benzodioxinyl, benzodithiinyl, benzoxazepinyl,
benzo-thiazepinyl, benzodiazepinyl, benzodioxepinyl,
benzodithiepinyl, benzoxazocinyl, benzothiazocinyl,
benzodiazocinyl, benzoxathiocinyl, benzo-dioxocinyl,
benzotrioxepinyl, benzoxathiazepinyl, benzoxadiazepinyl,
benzothiadiazepinyl, benzotriazepinyl, benzoxathiepinyl,
benzotriazinonyl, benzoxazolinonyl, azetidinonyl, azaspiroundecyl,
dithiaspirodecyl, selenazinyl, selenazolyl, selenophenyl,
hypoxanthinyl, azahypoxanthinyl, bipyrazinyl, bipyridinyl,
oxazolidinyl, diselenopyrimidinyl, benzodioxocinyl, benzopyrenyl,
benzopyranonyl, benzophenazinyl, benzoquinolizinyl,
dibenzocarbazolyl, dibenzoacridinyl, dibenzophenazinyl,
dibenzothiepinyl, dibenzooxepinyl, dibenzopyranonyl,
dibenzoquinoxalinyl, dibenzothiazepinyl, dibenzoisoquinolinyl,
tetraazaadamantyl, thiatetraazaadamantyl, oxauracil, oxazinyl,
dibenzothiophenyl, dibenzofuranyl, oxazolinyl, oxazolonyl,
azaindolyl, azolonyl, thiazolinyl, thiazolonyl, thiazolidinyl,
thiazanyl, pyrimidonyl, thiopyrimidonyl, thiamorpholinyl,
azlactonyl, naphtindazolyl, naphtindolyl, naphtothiazolyl,
naphtothioxolyl, naphtoxindolyl, naphtotriazolyl, naphtopyranyl,
oxabicycloheptyl, azabenzimidazolyl, azacycloheptyl, azacyclooctyl,
azacyclononyl, azabicyclononyl, tetrahydrofuryl, tetrahydropyranyl,
tetrahydropyronyl, tetrahydroquinoleinyl, tetrahydrothienyl and
dioxide thereof, dihydrothienyl dioxide, dioxindolyl, dioxinyl,
dioxenyl, dioxazinyl, thioxanyl, thioxolyl, thiourazolyl,
thiotriazolyl, thiopyranyl, thiopyronyl, coumarinyl, quinoleinyl,
oxyquinoleinyl, quinuclidinyl, xanthinyl, dihydropyranyl,
benzodihydrofuryl, benzothiopyronyl, benzothiopyranyl,
benzoxazinyl, benzoxazolyl, benzodioxolyl, benzodioxanyl,
benzothiadiazolyl, benzotriazinyl, benzothiazolyl, benzoxazolyl,
phenothioxinyl, phenothiazolyl, phenothienyl (benzothiofuranyl),
phenopyronyl, phenoxazolyl, pyridinyl, dihydropyridinyl,
tetrahydropyridinyl, piperidinyl, morpholinyl, thiomorpholinyl,
pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, tetrazinyl,
triazolyl, benzotriazolyl, tetrazolyl, imidazolyl, pyrazolyl,
thiazolyl, thiadiazolyl, isothiazolyl, oxazolyl, oxadiazolyl,
pyrrolyl, furyl, dihydrofuryl, furoyl, hydantoinyl, dioxolanyl,
dioxolyl, dithianyl, dithienyl, dithiinyl, thienyl, indolyl,
indazolyl, benzofuryl, quinolyl, quinazolinyl, quinoxalinyl,
carbazolyl, phenoxazinyl, phenothiazinyl, xanthenyl, purinyl,
benzothienyl, naphtothienyl, thianthrenyl, pyranyl, pyronyl,
benzopyronyl, isobenzofuranyl, chromenyl, phenoxathiinyl,
indolizinyl, quinolizinyl, isoquinolyl, phthalazinyl,
naphthiridinyl, cinnolinyl, pteridinyl, carbolinyl, acridinyl,
perimidinyl, phenanthrolinyl, phenazinyl, phenothiazinyl,
imidazolinyl, imidazolidinyl, benzimidazolyl, pyrazolinyl,
pyrazolidinyl, pyrrolinyl, pyrrolidinyl, piperazinyl, uridinyl,
thymidinyl, cytidinyl, azirinyl, aziridinyl, diazirinyl,
diaziridinyl, oxiranyl, oxaziridinyl, dioxiranyl, thiiranyl,
azetyl, dihydroazetyl, azetidinyl, oxetyl, oxetanyl, thietyl,
thietanyl, diazabicyclooctyl, diazetyl, diaziridinonyl,
diaziridinethionyl, chromanyl, chromanonyl, thiochromanyl,
thiochromanonyl, thiochromenyl, benzofuranyl, benzisothiazolyl,
benzocarbazolyl, benzochromonyl, benzisoalloxazinyl,
benzocoumarinyl, thiocoumarinyl, phenometoxazinyl,
phenoparoxazinyl, phentriazinyl, thiodiazinyl, thiodiazolyl,
indoxyl, thioindoxyl, benzodiazinyl (e.g. phtalazinyl), phtalidyl,
phtalimidinyl, phtalazonyl, alloxazinyl, dibenzopyronyl (i.e.
xanthonyl), xanthionyl, isatyl, isopyrazolyl, isopyrazolonyl,
urazolyl, urazinyl, uretinyl, uretidinyl, succinyl, succinimido,
benzylsultimyl, benzylsultamyl and the like, including all possible
isomeric forms thereof, wherein each carbon atom of said
heterocyclic ring may be independently substituted with a
substituent selected from the group consisting of halogen, nitro,
C.sub.1-7 alkyl (optionally containing one or more functions or
radicals selected from the group consisting of carbonyl (oxo),
alcohol (hydroxyl), ether (alkoxy), acetal, amino, imino, oximino,
alkyloximino, amino-acid, cyano, carboxylic acid ester or amide,
nitro, thio C.sub.1-7 alkyl, thio C.sub.3-10 cycloalkyl, C.sub.1-7
alkylamino, cycloalkylamino, alkenylamino, cycloalkenylamino,
alkynylamino, arylamino, arylalkylamino, hydroxylalkylamino,
mercaptoalkylamino, heterocyclic amino, hydrazino, alkylhydrazino,
phenylhydrazino, sulfonyl, sulfonamido and halogen), C.sub.2-7
alkenyl, C.sub.2-7 alkynyl, halo C.sub.1-7 alkyl, C.sub.3-10
cycloalkyl, aryl, arylalkyl, alkylaryl, alkylacyl, arylacyl,
hydroxyl, amino, C.sub.1-7 alkylamino, cycloalkylamino,
alkenylamino, cyclo-alkenylamino, alkynylamino, arylamino,
arylalkylamino, hydroxyalkylamino, mercaptoalkylamino, heterocyclic
amino, hydrazino, alkylhydrazino, phenylhydrazino, sulfhydryl,
C.sub.1-7 alkoxy, C.sub.3-10 cycloalkoxy, aryloxy, arylalkyloxy,
oxyheterocyclic, heterocyclic-substituted alkyloxy, thio C.sub.1-7
alkyl, thio C.sub.3-10 cycloalkyl, thioaryl, thioheterocyclic,
arylalkylthio, heterocyclic-substituted alkylthio, formyl,
hydroxylamino, cyano, carboxylic acid or esters or thioesters or
amides thereof, thiocarboxylic acid or esters or thioesters or
amides thereof; depending upon the number of unsaturations in the 3
to 10 membered ring, heterocyclic radicals may be sub-divided into
heteroaromatic (or "heteroaryl") radicals and non-aromatic
heterocyclic radicals; when a heteroatom of the said non-aromatic
heterocyclic radical is nitrogen, the latter may be substituted
with a substituent selected from the group consisting of C.sub.1-7
alkyl, C.sub.3-10 cycloalkyl, aryl, arylalkyl and alkylaryl.
[0095] As used herein with respect to a substituting radical, and
unless otherwise stated, the terms "C.sub.1-7 alkoxy", "C.sub.3-10
cycloalkoxy", "aryloxy", "arylalkyloxy", "oxyheterocyclic", "thio
C.sub.1-7 alkyl", "thio C.sub.3-10 cycloalkyl", "arylthio",
"arylalkylthio" and "thioheterocyclic" refer to substituents
wherein a C.sub.1-7 alkyl radical, respectively a C.sub.3-10
cycloalkyl, aryl, arylalkyl or heterocyclic radical (each of them
such as defined herein), are attached to an oxygen atom or a
divalent sulfur atom through a single bond, such as but not limited
to methoxy, ethoxy, propoxy, butoxy, pentoxy, isopropoxy,
sec-butoxy, tert-butoxy, isopentoxy, cyclopropyloxy, cyclobutyloxy,
cyclopentyloxy, thiomethyl, thioethyl, thiopropyl, thiobutyl,
thiopentyl, thiocyclopropyl, thiocyclobutyl, thiocyclopentyl,
thiophenyl, phenyloxy, benzyloxy, mercaptobenzyl, cresoxy, and the
like.
[0096] As used herein with respect to a substituting atom, and
unless otherwise stated, the term halogen means any atom selected
from the group consisting of fluorine, chlorine, bromine and
iodine.
[0097] As used herein with respect to a substituting radical, and
unless otherwise stated, the terms "arylalkyl", "arylalkenyl" and
"heterocyclic-substituted alkyl" refer to an aliphatic saturated or
unsaturated hydrocarbon monovalent radical (preferably a C.sub.1-7
alkyl or C.sub.2-7 alkenyl radical such as defined above) onto
which an aryl or heterocyclic radical (such as defined above) is
already bonded, and wherein the said aliphatic radical and/or the
said aryl or heterocyclic radical may be optionally substituted
with one or more substituents selected from the group consisting of
halogen, amino, nitro, hydroxyl, sulfhydryl and nitro, such as but
not limited to benzyl, 4-chlorobenzyl, phenylethyl,
1-amino-2-phenylethyl, 1-amino-2-[4-hydroxyphenyl]ethyl,
1-amino-2-[indol-2-yl]ethyl, styryl, pyridylmethyl, pyridylethyl,
2-(2-pyridyl)isopropyl, oxazolylbutyl, 2-thienylmethyl and
2-furylmethyl.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0098] The present invention will be described with respect to
particular embodiments but the invention is not limited thereto but
only by the claims.
[0099] It is to be noticed that the term "comprising", used in the
claims, should not be interpreted as being restricted to the means
listed thereafter; it does not exclude other elements or steps.
Thus, the scope of the expression "a device comprising means A and
B" should not be limited to devices consisting only of components A
and B. It means that with respect to the present invention, the
only relevant components of the device are A and B.
[0100] The compounds referred to in the detailed description may be
selected from the compounds described in the following list:
Compound (I) having the general formula:
##STR00018##
wherein Ar may be an aromatic or heteroaromatic divalent group. In
a preferred embodiment, Ar may comprise 4 to 20 carbon atoms. In
another embodiment, each of the Ar groups may be substituted with
one or more substituents independently selected from the group
consisting of C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-alkoxy,
C.sub.1-C.sub.20-alkylsulfate, oligo or poly(ethylene oxide) (PEO),
oligo or poly(ethylene glycol) (PEG), a phenyl group or a benzyl
group. These Ar groups may comprise up to 4 heteroatoms chosen from
the group comprising oxygen, sulphur, and nitrogen in the aromatic
cyclic system. The substituents on Ar groups may be independently
linear, or cyclic, or two of these substituents may be linked
together to form a cycle on the Ar group.
[0101] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
[0102] R.sub.0 may be an aromatic divalent group or a
heteroaromatic divalent group consisting of an amine
--NR.sub.1R.sub.2, a C.sub.5-C.sub.20 alkyloxy group, an aryloxy
group, an alkyl group, an aryl group, an alkylaryl group, an
arylalkyl group, a thioether group, an ester group, an acid
carboxylic group.
[0103] In a preferred embodiment, R.sub.0 may be an amine
--NR.sub.1R.sub.2, in which R.sub.1 and R.sub.2 are independently
from each other an organic group selected from the group consisting
of a C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.3-C.sub.20-alkyl
group, an aryl group, an alkylaryl group, an arylalkyl group and a
heterocyclic group, R.sub.1 and R.sub.2 may be linked together to
form a cycle. Preferably, R.sub.1 and R.sub.2 may be independently
selected from a methyl group, an ethyl group, a propyl group, a
phenyl group and a benzyl group. The alkyl group, phenyl group and
benzyl group may comprise heteroatoms and substituents.
Compound (II) having the general formula
##STR00019##
wherein Ar may be an aromatic or heteroaromatic divalent group. In
a preferred embodiment, Ar may comprise 4 to 20 carbon atoms. In
another embodiment, each of the recited Ar groups may be
substituted with one or more independently selected substituents
chosen from the group consisting of a C.sub.1-C.sub.20-alkyl,
C.sub.3-C.sub.20-alkoxy, C.sub.1-C.sub.20-alkylsulfate, oligo or
poly(ethylene oxide) (PEO), oligo or poly(ethylene glycol) (PEG), a
phenyl or a benzyl group and these Ar groups may comprise up to 4
heteroatoms chosen from the group comprising oxygen, sulphur, and
nitrogen in the aromatic cyclic system. The substituents on the Ar
groups may be independently linear, or cyclic, or two of these
groups may be linked together to form a cycle on the Ar group.
[0104] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
[0105] R.sub.0 may be an aromatic divalent group or a
heteroaromatic divalent group consisting of an amine
--NR.sub.1R.sub.2, a C.sub.5-C.sub.20 alkyloxy group, an aryloxy
group, an alkyl group, an aryl group, an alkylaryl group, an
arylalkyl group, a thioether group, an ester group, an acid
carboxylic group.
[0106] In a preferred embodiment, R.sub.0 may be an amine
--NR.sub.1R.sub.2,
##STR00020##
[0107] in which R.sub.1 and R.sub.2 are independently from each
other an organic group selected from the group consisting of a
C.sub.1-C.sub.20-alkyl group, a cyclic C.sub.3-C.sub.20-alkyl
group, an aryl group, an alkylaryl group, an arylalkyl group and a
heterocyclic group, R.sub.1 and R.sub.2 may be linked together to
form a cycle. Preferably, R.sub.1 and R.sub.2 may be independently
selected from a methyl group, an ethyl group, a propyl group, a
phenyl group and a benzyl group. The alkyl group, phenyl group and
benzyl group may comprise heteroatoms and substituents. One typical
example of such a precursor polymer may be a precursor polymer
wherein R.sub.0=--NR.sub.1R.sub.2 and wherein
R.sub.1=R.sub.2=Et:
##STR00021##
[0108] In other specific examples of precursor polymers which may
be used according to embodiments, Ro may be a phenyl group (Ph), a
methyl group (CH.sub.3) or a group (F.sub.6C.sub.6O):
##STR00022##
[0109] In other specific examples, precursor polymers may be based
on poly(p-phenylene vinylene) derivatives, such as for example
alkoxy poly(p-phenylene vinylene) (alkoxy-PPV) derivatives such as
e.g. poly(2-methoxy, 5-3',7'-dimethyloctyloxy)-1,4-phenylene
vinylene (MDMO-PPV or OC.sub.1C.sub.10PPV), or on poly(p-thienylene
vinylene) (PTV) derivative, and R.sub.3 and R.sub.4 may be chosen
from the group comprising a hydrogen atom, a C.sub.1-C.sub.20-alkyl
group, a cyclic C.sub.4-C.sub.20-alkyl group, a phenyl group and a
benzyl group, which groups may comprise heteroatoms and
substituents. In a preferred embodiment, R.sub.3 and R.sub.4 may be
hydrogen.
Compound (III) having the general formula
##STR00023##
wherein Ar may be an aromatic or heteroaromatic divalent group. In
a preferred embodiment, Ar comprises 4 to 20 carbon atoms. In
another embodiment, each of the Ar groups may be substituted with
one or more independently selected substituents chosen from the
group consisting of a C.sub.1-C.sub.20-alkyl,
C.sub.3-C.sub.20-alkoxy, C.sub.1-C.sub.20-alkylsulfate, oligo or
poly(ethylene oxide) (PEO), oligo or poly(ethylene glycol) (PEG), a
phenyl or a benzyl group and these Ar groups may comprise up to 4
heteroatoms chosen from the group comprising oxygen, sulphur, and
nitrogen in the aromatic divalent group. The substituents on Ar
groups may be independently linear, or cyclic, or two of these
substituents may be linked together to form a cycle on the Ar
group.
[0110] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
[0111] R.sub.3 and R.sub.4 may be chosen from the group comprising
a hydrogen atom and a C.sub.1-C.sub.20-alkyl group, a cyclic
C.sub.4-C.sub.20-alkyl group, a phenyl group and a benzyl group,
which groups may comprise heteroatoms and substituents. In a
preferred embodiment, R.sub.3 and R.sub.4 may be hydrogen.
Compound (IV) having the general formula
##STR00024##
wherein Ar may be an aromatic or heteroaromatic divalent group. In
a preferred embodiment, Ar may comprise 4 to 20 carbon atoms. In
another embodiment, each of the Ar groups may be substituted with
one or more substituents independently chosen from the group
consisting of a C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-alkoxy,
C.sub.1-C.sub.20-alkylsulfate, oligo or poly(ethylene oxide) (PEO),
oligo or poly(ethylene glycol) (PEG), a phenyl or a benzyl group
and these Ar groups may comprise up to 4 heteroatoms chosen from
the group comprising oxygen, sulphur, and nitrogen in the aromatic
cyclic system. The substituents on the Ar groups may be
independently linear, or cyclic, or two of these substituents may
be linked together to form a cycle on the Ar group.
[0112] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
[0113] X may be selected from the group consisting of Cl, Br or
F.
[0114] R.sub.5 and R.sub.6 may be selected from the group
consisting of a C.sub.1-C.sub.20-alkyl group, a cyclic
C.sub.4-C.sub.20-alkyl group, a phenyl group and a benzyl group,
which groups may comprise heteroatoms and substituents.
Compound (V) having the general formula
Y--Ar--Y (V)
wherein Y may comprise chloromethyl, bromomethyl or fluoromethyl
atoms and wherein Ar may be an aromatic or heteroaromatic divalent
group. In a preferred embodiment, Ar may comprise 4 to 20 carbon
atoms. In another embodiment, each of the Ar groups may be
substituted with one or more substituents independently chosen from
the group consisting of a C.sub.1-C.sub.20-alkyl,
C.sub.3-C.sub.20-alkoxy, C.sub.1-C.sub.20-alkylsulfate, oligo or
poly(ethylene oxide) (PEO), oligo or poly(ethylene glycol) (PEG), a
phenyl or a benzyl group and these Ar groups may comprise up to 4
heteroatoms chosen from the group comprising oxygen, sulphur, and
nitrogen in the aromatic cyclic system. The substituents on the Ar
groups may be independently linear, or cyclic, or two of these
substituents may be linked together to form a cycle on the Ar
group.
[0115] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl. Preferably, Ar may be 1,4-phenylene or
2,5-thienylene and most preferably Ar may be 2,5-thienylene.
Compound (VI) having the general formula
##STR00025##
wherein Z may be a leaving group. In a preferred embodiment, Z may
be selected from the group consisting of Cl, Br, I, --O-Tos,
--O-Mes, --O-Triflates, --(NR.sub.1 R.sub.1 R.sub.1).sup.+,
--(SR.sub.1R.sub.2).sup.+, --OOCR.sub.1 and --SC(S)OR.sub.1. In the
above formula, Y may be a polarizer group and may be selected form
the group consisting of --SR.sub.1, --OR.sub.1, --OH, --Cl, --Br,
--SO--R.sub.1, --CN, --CO--OR.sub.1 and --S--C(S)OR.sub.1, R.sub.7
and R.sub.8 may independently be --H, R.sub.1, and Ar may be an
aromatic or heteroaromatic divalent group. In a preferred
embodiment, Ar may comprise 4 to 20 carbon atoms. In another
embodiment, each of the Ar groups may be substituted with one or
more substituents independently chosen from the group consisting of
a C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.20-alkoxy,
C.sub.1-C.sub.20-alkylsulfate, oligo or poly(ethylene oxide) (PEO),
oligo or poly(ethylene glycol) (PEG), a phenyl or a benzyl group
and these Ar groups may comprise up to 4 heteroatoms chosen from
the group comprising oxygen, sulphur, and nitrogen in the aromatic
divalent group.
[0116] In a further embodiment, the aromatic or heteroaromatic
divalent group may be selected from the group consisting of
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,5-furanediyl; 2,5-pyrrolediyl;
1,3,4-oxadiazole-2,5-diyl; 1,3,4-thiadiazole-2,5-diyl;
2,5-benzo[c]thienylene; thieno[3,2-b]thiophene-2,5-diyl;
pyrrolo[3,2-b]pyrrole-2,5-diyl; pyrene-2,7-diyl;
4,5,9,10-tetrahydropyrene-2,7-diyl; 4,4'-bi-phenylene;
phenantrene-2,7-diyl; 9,10-dihydrophenantrene-2,7-diyl;
dibenzofurane-2,7-diyl; dibenzothiophene-2,7-diyl. Preferably, Ar
may be 1,4-phenylene or 2,5-thienylene and most preferably Ar may
be 2,5-thienylene.
[0117] R.sub.1, R.sub.2, R.sub.3 may be equal to R.sub.1, R.sub.2,
R.sub.3 as defined for compound (II).
[0118] In a first aspect, the synthesis of a soluble precursor
polymer (II) starting from the monomer (I) is provided. An
embodiment also provides the synthesis of monomer (I). The second
aspect comprises the conversion reaction of the soluble precursor
polymer to the related conjugated polymer which may be soluble or
insoluble depending on the chemical structure. The method does not
require the use of chain end controlling agents during the
polymerisation reaction as the obtained precursor polymers are
always soluble whatever the Ar groups are.
[0119] Furthermore, an embodiment comprises the manufacturing of an
active layer from the precursor polymer. The last step is the
electronic device made from the precursor polymer followed by its
conversion reaction towards the conjugated polymer as pristine
material or in blend.
[0120] The first aspect thus provides the synthesis of a soluble
precursor polymer (II). Therefore, first a monomer has to be
provided. Therefore, as an example and not limiting to the
invention, a dithiocarbamic acid sodium salt is added in the solid
state to an aromatic or heteroaromatic ring structure of the
general formula of compound (IV) or to an aromatic or
heteroaromatic ring structure with general formula of compound (V)
in a mixture of organic solvents. After stirring a few hours at
room temperature, the reaction product may be extracted with for
example ether and dried over magnesium sulphate. The product of
that reaction is an arylene or heteroarylene group bearing two
dithiocarbamate groups in para positions as described in formula
(I).
[0121] Mono- and bis-dithiocarbamate molecules may in this
invention be used as photoiniferters. An example of such a
bifunctional iniferter is p-xylylene bis(N,N-diethyl
dithiocarbamate). It was first synthesised in 1984 by Otsu et al
(T. Otsu, A. Kuriyama, Polym. Bull. 1984, 11, 2, 135), and was used
for the living radical polymerisation of styrene and methyl
methacrylate. Otsu wrote an extensive review on the iniferter
concept and living radical polymerisation (T. Otsu, J. Polym. Sci.,
Part A: Polym. Chem. 2000, 38, 12, 2121). The use of p-xylylene
bis(N,N-diethyl dithiocarbamate) as a monomer in a polymerisation
process was not found.
[0122] The synthesis of thiophene-2,5-diylbismethylene N,N-diethyl
thiocarbamate was patented by Nishiyama et al. in 1975 for its
herbicidal activities (Jpn. Tokkyo Koho, No 50004732, 1975), but
again no report exists on the use of the dithiocarbamate
"thiophene" analogue as a monomer for polymerisation to soluble
precursor polymers which may be converted by thermal elimination
(leaving groups eliminated) towards the conjugated semiconductors,
which may be soluble or insoluble, depending on their chemical
structure.
[0123] According to the first aspect the monomer having the general
formula (I) is reacted with a basic compound in the presence of an
organic solvent to obtain the soluble precursor polymer (II). It
has to be noted that no chain end controlling agents are required
to obtain this soluble precursor polymer (II).
[0124] A mixture of different starting monomers of formula (I) may
be reacted by using the above method, leading to copolymers.
Alternatively, a mixture of different starting monomers of formula
(I) and of formula (VI) may be polymerised by using this method
leading to copolymers. Those copolymers may then be used as
polyiniferters in iniferter controlled free-radical polymerisation
to the synthesis of block copolymers and grafted polymers.
[0125] The precursor polymers in accordance with the formula (II),
that may be prepared by an embodiment, preferably may comprise as
the Ar group an aromatic or heteroaromatic group chosen from
1,4-phenylene; 2,6-naphthalenediyl; 1,4-naphthalenediyl;
1,4-anthracenediyl; 2,6-anthracenediyl; 9,10-anthracenediyl;
2,5-thienylene; 2,4-thienylene; 2,3-thienylene; 2,5-furanediyl;
2,5-pyrrolediyl; 1,3,4-oxadiazole-2,5-diyl;
1,3,4-thiadiazole-2,5-diyl; 2,5-benzo[c]thienylene;
thieno[3,2-b]thiophene-2,5-diyl; pyrrolo[3,2-b]pyrrole-2,5-diyl;
pyrene-2,7-diyl; 4,5,9,10-tetrahydropyrene-2,7-diyl;
4,4'-bi-phenylene; phenantrene-2,7-diyl;
9,10-dihydrophenantrene-2,7-diyl; dibenzofurane-2,7-diyl;
dibenzothiophene-2,7-diyl; carbazole-2,7-diyl, of which the
nitrogen-containing groups may be substituted on the nitrogen atom
with a C.sub.1-C.sub.22-alkyl or a C.sub.2-C.sub.10-aryl group,
while in all groups the R atoms on the aromatic rings may be
substituted by a C.sub.1-C.sub.22 linear, cyclic or branched alkyl
group, C.sub.4-C.sub.14 aryl group, electron-donating groups such
as C.sub.1-C.sub.22 alkoxy and alkylthio groups, and halogen atoms
or electron-attracting groups such as cyano, nitro, and ester
groups, while the C.sub.1-C.sub.14 aryl group itself may be
substituted by electron-donating or electron-attracting groups.
[0126] The basic compound may be a metal base, an ammonium base or
a non-charged base such as amines like for example triethylamine,
pyridine and non-ionic phosphazene bases. The metal in these basic
compounds may preferably be an alkali metal or an alkali earth
metal, i.e. a metal from group I or II. Classes of metal and
ammonium bases are metal hydrides, such as NaH or KH, metal
hydroxides, such as NaOH, LiOH or KOH, metal alkoxides, such as
NaOMe or NaOEt; KotBu; metal amines such as a lithium-ammonia
solution, a sodium-ammonia solution, lithium in methylamine; metal
amides, such as NaNH.sub.2, NaN(SiMe.sub.3).sub.2,
lithiumdiisopropylamide (LDA), organometal compounds wherein the
metal is an alkali metal or alkali earth metal, such as for example
a C.sub.1-20 alkyl lithium (e.g. n-BuLi) or a C.sub.1-20 alkyl
sodium, Grignard reagents, and ammonium hydroxides. Grignard
reagents are organic magnesium halides preferably dissolved in a
non-reactive solvent (typically dry ethyl ether). The substance is
made up of an organic group, e.g. an alkyl or aryl group, joined by
a highly polar covalent bond to magnesium, while the magnesium is
joined by an ionic bond to a halogen ion e.g. bromide or
iodide.
[0127] The amount of basic compound may vary from 1 to 2
equivalents with respect to the starting monomer. It may be
preferred to use one equivalent of basic compound because a too
high concentration of basic compound may induce an in situ
conversion reaction during the polymerisation.
[0128] In polar aprotic solvents it is preferred to use metal
hydrides as they show substantially no nucleophilic properties. In
polar protic solvents it is preferred to use bases with a pKa
larger than the pKa of the solvent. In this case the solvent is
deprotonated and acts as the actual basic compound. In the method
of an embodiment, it may be preferred to use an aprotic solvent. A
mixture of solvents may also be used. Examples of solvents which
may be used are for example amides of the general formula
R.sub.5--CONR.sub.6H, amines of the general formula
R.sub.7R.sub.7--N--R.sub.8, sulfones of the general formula
R.sub.8--SO.sub.2--R.sub.9, sulfoxides of the general formula
R.sub.8--SO--R.sub.9, a solvent from the group consisting of
alcohols, such as for example sec-butanol and all linear or
branched C.sub.nH.sub.2n+2O where 1.ltoreq.n.ltoreq.20, glycols,
polyethers, cyclic ethers, unsaturated ethers, wherein R.sub.5,
R.sub.6 are the same or different and denote H, a linear or
branched alkyl group, or R.sub.5 and R.sub.6 together are
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.3--,
CH.sub.2--CH.dbd.CH.sub.2--CH.sub.2 or --(CH.sub.2).sub.4--; and
R.sub.7 has the meaning of R.sub.5 or is a phenyl group which is
unsubstituted or substituted by halogen, methyl and/or methoxy
groups; and R.sub.8, R.sub.9 are the same or different and have the
meaning of R.sub.7, except H, or R.sub.8 and R.sub.9 together are
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.3--, --(CH.sub.2).sub.4-- or
--CH.sub.2--CH.dbd.CH--CH.sub.2--.
[0129] The concentration of starting monomer (I) may be determined
by the solubility of the monomer (I). All concentration of the
starting monomer (I) in a solvent may be used as long as the
monomer (I) is still fully soluble. However, a concentration of
between 0.1 M and 0.3 M may generally be preferred.
[0130] In a preferred embodiment, a solution of the monomer of
formula (I) or a mixture of at least two monomers of formula (I) at
a giving temperature may be degassed for a giving time by passing
through a continuous nitrogen flow. A basic compound dissolved in
an organic solvent may then be added in one-go to the stirred
monomer solution. The polymer may then be precipitated in ice-cold
water and extracted, washed and dried. The precursor polymer with
structural units of formula (II) such obtained is fully soluble in
common organic solvents such as for example THF, cyclohexanone,
DMF, chloroform, DMSO, toluene, benzene, dichlorobenzene,
dichloromethane, acetone, dioxane and shows an average molecular
weight (Mw) between 5.000 and 1.000.000 and a polydispersity
between 2 and 15 measured by gel permeation chromatography relative
to polystyrene standards.
[0131] In a second aspect, the precursor polymer (II) formed in the
first aspect, is converted into the corresponding soluble or
insoluble conjugated polymer having the general formula (III).
[0132] The soluble precursor polymer may be converted into the
corresponding conjugated polymer with units of structural formula
(III) in two ways: [0133] 1. by elimination of the leaving groups
and formation of the vinylene double bonds by thermal heating of
the precursor polymer solution under inert atmosphere or [0134] 2.
by elimination of the leaving groups and formation of the vinylene
double bonds by thermal heating in thin film. The thin films are
prepared from the soluble precursor polymer by, for example,
spin-coating, drop-casting, ink-jet printing or doctor-blading or
any other film-making techniques, and converted by heating under
vacuum or under inert atmosphere. The conversion in thin film is
preferred when the conjugated polymer is expected to be insoluble,
therefore the conversion of the soluble precursor polymer towards
the conjugated polymer is made in situ in thin film.
[0135] In one embodiment, the polymer (III) may be formed by
performing the conversion step of the soluble precursor polymer
towards the soluble conjugated polymer in solution. The conversion
in solution is preferably when the conjugated polymer is a soluble
polymer. The precursor polymer (II) may be subjected to a thermal
conversion step at a temperature between 30.degree. C. and
300.degree. C. The conversion reaction of the precursor polymer
(II) starts around 100.degree. C. and is completed at around
250-300.degree. C. depending on the chemical structure of the
polymer. In this embodiment, the precursor polymer (II) may thus be
dissolved in a solvent in a giving concentration, typically 0.1 M,
and is degassed by passing through a continuous nitrogen flow for,
for example, 1 hour. The temperature may then be increased and the
inert atmosphere is maintained during the conversion reaction and
the cooling down. A typical procedure comprises heating a ramp from
room temperature to the conversion temperature at 2.degree. C./min,
followed by isotherm at the conversion temperature for 3 hours and
cooling down to room temperature. In another embodiment, more than
one cycle as described above may be applied to the polymer.
[0136] In still another embodiment, the soluble or insoluble
conjugated polymer (III) may be formed by performing the conversion
step in thin film. Herefore, glass substrates coated with indium
tin oxide (ITO) are cleaned with isopropanol in an ultrasonic bath
for 20 minutes and dried in nitrogen flow. The precursor polymer
(II) may then be coated on the glass substrate from solution. A
two-step process may be used. A first step determines the film
thickness and may be done with a closed cover for, for example, 5
seconds at 600 rpm. In a second step the film may be dried with an
open cover for, for example, 2 minutes at 40 rpm.
[0137] The conversion of the precursor polymer (II) towards the
soluble or insoluble conjugated polymer in thin film may be done in
a glove box under inert atmosphere on a hot plate from room
temperature to the conversion temperature at 2.degree. C./min
followed by 10 minutes at the conversion temperature. The
conversion reaction may be carried out also under vacuum
conditions.
[0138] The polymer (III) is preferably kept under inert
atmosphere.
[0139] In a further embodiment, an annealing treatment of the
soluble or insoluble conjugated polymer in thin film may be carried
out at a temperature of between 30.degree. C. and 200.degree. C.
during 1 minute to 2 hours under vacuum or inert atmosphere in
order to remove stresses of the polymer chains introduced during
the deposition of the thin film layer and in order to induce a
relaxation of the conjugated polymer chains and to change the
conjugated polymer film morphology. No changes occur in the
chemical structure of the conjugated polymer during this annealing
treatment (heat treatment on conjugated polymer), in contrary to
the conversion reaction (heat treatment on precursor polymer) which
involves, under heating, an elimination of the leaving groups of
the soluble precursor polymer with the formation of vinylene double
bonds. This annealing treatment may be carried out before or after
the electrode deposition on top of the active conjugated polymer
layer.
[0140] According to the previous embodiment, the conversion of the
precursor polymer (II) may be performed until substantially all
leaving groups are eliminated. However, a conjugated polymer may
not be fully, i.e. 100%, conjugated because there can always be
structural defects which can lead to about 2 to 8%, in most cases
between 2 to 5%, of the resulting polymer that has not been
conjugated. Therefore, a reference herein to a conjugated polymer
may include within its scope a deviation from complete conjugation
of about 2 to 5%.
[0141] In still another embodiment, the conversion of the precursor
polymer may be performed only partially. Hence, in the resulting
partially converted conjugated polymer, there may still be leaving
groups present. The percentage of remaining leaving groups within
the resulting conjugated polymer may be tuned by changing the
experimental conditions such as, for example, temperature,
conversion time, atmosphere. The amount of remaining leaving groups
may be between 0 and 10%. For example, if the percentage of the
remaining leaving groups is 5%, it means that there are, in the
resulting partially converted conjugated polymer, for 100 monomer
units 5 monomer units still having a leaving group and 95 monomer
units not having a leaving group.
[0142] In a specific, preferred embodiment, the conjugated arylene
or heteroarylene vinylene polymer is a poly(2,5-thienylene
vinylene) or PTV polymer with formula:
##STR00026##
[0143] Due to the fact that the polymer is prepared by a method as
described herein, the poly(2,5-thienylene vinylene) polymer
according to an embodiment shows a peak at a wavelength higher than
520 nm in the absorption spectrum.
[0144] In another embodiment, also other PTV derivatives, which
have side chains on the 2 and 3 positions (instead of on the 2 and
5 positions in the previous embodiment) on the thiophene ring may
be used.
[0145] In a third aspect, an electronic device comprising a polymer
according to formula (III) is disclosed. The electronic devices may
be, but are not limited hereto, for example organic field effect
transistors, bilayer heterojunction organic solar cells and bulk
heterojunction organic solar cells. During the processing of the
electronic devices, the precursor polymer (II) may be deposited and
subsequently subjected to a thermal conversion step (according to
the second aspect) such that an active layer may be formed.
[0146] According to the third aspect, an organic bulk
heterojunction solar cell with acceptable efficiency may be
prepared from the precursor polymer (II). This may be advantageous
over prior art methods, where the conjugated polymer is the
starting compound and hence must be soluble to be mixed with a
soluble C.sub.60 derivative (for example PCBM). As the conversion
temperature of the precursor polymer of formula (II) starts
relatively at low temperature (e.g. 100-115.degree. C.), it may be
possible to prepare a blend n-type/p-type, used as active layer, by
mixing the precursor polymer (II) with PCBM and then carrying out
the conversion reaction by heat treatment in thin film keeping the
initial chemical structure of PCBM and converting simultaneously
the soluble precursor polymer to the soluble or insoluble
conjugated polymer. Furthermore, any other p-type material being a
small molecule or an oligomer or a polymer other than C.sub.60 or
PCBM and having a chemical structure stable at the temperature used
during the conversion reaction of the precursor polymer towards the
conjugated polymer may be also considered.
[0147] For the bulk heterojunction solar cells in accordance to the
third aspect the precursor polymer may contain the structural units
of formula (II) wherein R.sub.1, R.sub.2 may be as described in
formula (II) and wherein Ar may be 2,5-thienylene, which may be
substituted on its 3 and 4 positions by a C.sub.1-C.sub.22 linear
or branched alkyl group, C.sub.4-C.sub.14 aryl group,
electron-donating groups such as C.sub.1-C.sub.22 linear or
branched alkoxy and alkylthio groups, and halogen atoms or
electron-attracting groups such as cyano, nitro, and ester groups,
while the C.sub.1-C.sub.14 aryl group itself may be substituted by
electron-donating or electron-attracting groups, and the two
substituent groups on the Ar group may be linked together to form a
cycle on the Ar group, and a soluble C.sub.60 derivative may be
used as n-type material, such as PCBM. The active layer may be
obtained by carrying out the conversion reaction by heat treatment
of the thin film keeping intact the initial chemical structure of
the soluble C.sub.60 derivative.
[0148] A fourth aspect comprises the manufacturing of bilayer
organic solar cells, organic transistors and LED's having an active
layer made from a precursor polymer containing structural units of
formula (II) which is in situ converted to the active soluble or
insoluble conjugated polymer.
[0149] Furthermore, bilayer organic solar cells in accordance with
the fourth aspect are disclosed wherein the precursor polymer may
comprise the structural units of formula (II) wherein R.sub.0 may
be as described in formula (II) and wherein Ar may be
2,5-thienylene, which may be substituted on its 3 and/or 4
positions by a C.sub.1-C.sub.22 linear or branched alkyl group,
C.sub.4-C.sub.14 aryl group, electron-donating groups such as
C.sub.1-C.sub.22 linear, cyclic or branched alkoxy and alkylthio
groups, and halogen atoms or electron-attracting groups such as
cyano, nitro, and ester groups, while the C.sub.1-C.sub.14 aryl
group itself may be substituted by electron-donating or
electron-attracting groups. At least two of these independently
chosen substituents may, in one embodiment, be linked together to
form a cyclic structure on the Ar group between the 3 and 4
positions. The active layer may be obtained by carrying out the
conversion reaction by heat treatment of the thin film.
[0150] Furthermore, organic transistors in accordance with the
fourth aspect are disclosed wherein the precursor polymer may
comprise the structural units of formula (II) wherein R.sub.0 may
be as described in formula (II) and wherein Ar may be
2,5-thienylene which may be substituted on its 3 and 4 positions by
a C.sub.1-C.sub.22 linear or branched alkyl group, C.sub.4-C.sub.14
aryl group, electron-donating groups such as C.sub.1-C.sub.22
linear or branched alkoxy and alkylthio groups, oligo- or
poly(ethylene oxide) (PEO), oligo- or poly(ethylene glycol) (PEG),
and halogen atoms or electron-attracting groups such as cyano,
nitro, and ester groups, while the C.sub.1-C.sub.14 aryl group
itself may be substituted by electron-donating or
electron-attracting groups. At least two of these independently
chosen substituents may, in one embodiment, be linked together to
form a cyclic structure on the Ar group between the 3 and 4
positions. The active layer may be obtained by carrying out the
conversion reaction of the precursor polymer towards the related
soluble or insoluble conjugated polymer by heat treatment of the
thin film.
[0151] Furthermore, Light emitting diodes (LED) in accordance with
the fourth aspect are disclosed wherein the LED may comprise a
substrate having deposited thereon successively a thin film of a
soluble precursor polymer according to structural formula (II),
prepared in accordance to the first aspect and converted to the
conjugated polymer with structural formula (III) by heat treatment
in accordance with the second aspect and a layer of an electrical
conductor together with means for biasing the thin film and
conductor.
Example 1
[0152] In a first example the synthesis of p-xylylene
bis(N,N-diethyl dithiocarbamate) with a formula according to
formula (I) wherein Ar=1,4-phenylene, R.sub.0=--NR.sub.1R.sub.2
with R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5, followed by the
polymerisation to the precursor polymer with a formula according to
formula (II) wherein Ar=1,4-phenylene, R.sub.0=--NR.sub.1R.sub.2
with R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5,
R.sub.3.dbd.R.sub.4.dbd.H and subsequent conversion to the
conjugated polymer with a formula according to formula (III)
wherein Ar=1,4-phenylene, R.sub.3.dbd.R.sub.4.dbd.H is
illustrated.
[0153] To 50 ml of an acetonitrile/water solution (5% vol water) of
1,4-bis(tetrahydrothiopheniomethyl)xylene dichloride (6 g, 17.143
mmol), diethyldithiocarbamic acid sodium salt trihydrate (8.87 g,
39.429 mmol) is added as a solid, after which the mixture is
stirred at ambient temperature for two hours. Then, water is added
and the desired monomer is extracted with ether (3.times.100 ml)
and dried over MgSO.sub.4. Evaporation of the solvent yields 6.2 g,
which is 90%, of the pure product as a white solid. .sup.1H NMR
(CDCl.sub.3): 7.31 (s, 4H), 4.49 (s, 4H), 4.01 (q, J=7.2 Hz, 4H),
3.69 (q, J=7.2 Hz, 4H), 1.25 (2t, J=7.2 Hz, 12H). .sup.13C NMR
(CDCl.sub.3): 195.10, 135.27, 129.57, 49.46, 46.70, 41.79, 12.44,
11.56; MS (EI, m/e): 253 (M.sup.+-SC(S)NEt.sub.2), 148
(SC(S)NEt.sub.2), 105 (M.sup.+-2.times.SC(S)NEt.sub.2), 72
(NEt.sub.2)
[0154] A solution of the synthesised monomer p-xylene
bis(N,N-diethyldithiocarbamate) (500 mg, 1.25 mmol) in dry THF
(6.25 ml, 0.2 M) at -78.degree. C. (or RT or 0.degree. C.) is
degassed for 1 hour by passing through a continuous nitrogen flow.
An equimolar LDA solution (625 .mu.l of a 2 M solution in THF) is
added in one go to the stirred monomer solution. The THF from the
basic solution is neglected in the calculation of the monomer
concentration. The mixture is then kept at -78.degree. C. (or R.T
or 0.degree. C.) for 90 minutes while the passing of nitrogen is
continued. After this, the solution is allowed to come to 0.degree.
C. or ethanol (6 ml) is added at -78.degree. C. to stop the
reaction (this is not necessary if the polymerisation is performed
at RT or 0.degree. C.). The polymer is then precipitated in ice
water (100 ml) and extracted with chloroform (3.times.60 ml). The
solvent of the combined organic layers is evaporated under reduced
pressure and a second precipitation is performed in a 1/1 mixture
(100 ml) of diethyl ether and hexane at 0.degree. C. The polymer
was collected and dried in vacuum. .sup.1H NMR (CDCl.sub.3):
6.78-7.14 (br s, 4H), 5.00-5.30 (br s, 1H), 3.82-4.10 (br s, 2H),
3.51-3.78 (br s, 2H), 2.92-3.12 (br s, 2H), 1.04-1.34 (br t, 6H).
.sup.13C NMR (CDCl.sub.3): 194.38, 138.07, 137.17, 129.35, 128.30,
56.92, 49.15, 46.68, 42.63, 12.58, 11.65. The residual fractions
only contained monomer residues. Polymerisation experiments are
carried out at different temperatures. The results are summarised
in table 1. In this table, Mw denotes the molecular weight and PD
the polydispersity of the conjugated polymer.
TABLE-US-00001 TABLE 1 Starting monomer with structural units of
formula (I) with: Ar = 1,4-phenylene, R.sub.0 = --NR.sub.1R.sub.2
with R.sub.1.ident.R.sub.2 = Et in THF. Conc. Polymerisation Yield
Mw (M) temp. (.degree. C.) (%) (g/mol) PD 0.2 -78 90 7300 1.5 -78
to 0 88 15000 2.1 0 87 31200 4.1 RT 88 36500 5.5
Example 2
[0155] In a second example, the synthesis of
thiophene-2,5-diylbismethylene N,N-diethyl dithiocarbamate with a
formula according to formula (I) wherein Ar=2,5-thienylene and
R.sub.0=--NR.sub.1R.sub.2 with
R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5, followed by polymerisation
to the precursor polymer with a formula according to formula (II)
wherein Ar=2,5-thienylene, R.sub.0=--NR.sub.1R.sub.2 with
R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5 and
R.sub.3.dbd.R.sub.4.dbd.H, and subsequent conversion to the
conjugated polymer with a formula according to formula (III)
wherein Ar=2,5-thienylene and R.sub.3.dbd.R.sub.4.dbd.H, is
illustrated.
[0156] The preparation of the monomer is analogous to that
described in example 1, but here a bis-sulphonium salt of formula
(IV) where Ar=2,5-thienylene is used. The yield of the reaction is
81%; .sup.1H NMR (CDCl.sub.3): 6.84 (s, 2H), 4.69 (s, 4H), 4.01 (q,
J=7.2 Hz, 4H), 3.69 (q, J=7.2 Hz, 4H), 1.26 (t, J=7.2 Hz, 12H);
.sup.13C NMR (CDCl.sub.3): 194.29, 138.76, 126.77, 49.46, 46.70,
36.72, 12.46, 11.53; MS (EI, m/e): 258 (M.sup.+-SC(S)NEt.sub.2),
148 (SC(S)NEt.sub.2)
[0157] The polymerisation of thiophene-2,5-diylbismethylene
N,N-diethyl dithiocarbamate is analogous to that described in
example 1. .sup.1H NMR (CDCl.sub.3): 6.56-6.72 (br s, 1H),
6.72-6.36 (br s, 1H), 5.22-5.55 (br s, 1H), 3.81-4.12 (br q, 2H),
3.48-3.81 (br q, 2H), 3.11-3.40 (br s, 2H), 1.01-1.37 (br t, 6H).
.sup.13C NMR (CDCl.sub.3): 193.61, 140.77, 140.36, 126.15, 125.89,
52.50, 49.20, 46.73, 38.37, 12.45, 11.60.
[0158] In this example, polymerisation experiments are carried out
at different temperatures and with different concentrations of
starting monomer. The results of these experiments are summarised
in table 2.
TABLE-US-00002 TABLE 2 Starting monomer with structural units of
formula (I) with: Ar = 2,5-thienylene, R.sub.0 = --NR.sub.1R.sub.2
with R.sub.1.ident.R.sub.2 = Et in THF. Conc. Polymerisation Yield
Mw (M) temp. (.degree. C.) (%) (g/mol) PD 0.1 -78 47 62800 2.9 -78
to 0 55 90000 5.3 0 42 23800 3.8 0.2 -78 57 94400 3.1 -78 to 0 56
66100 4.9 0.3 -78 to 0 53 12800 1.4
[0159] An organic field effect transistor is then prepared
according to the following procedure using the soluble precursor
polymer synthesised in accordance with the method described in this
embodiment. Field-effect transistors (FETs) may be made of high
doped Si substrates. In this example, an isolating oxide
(SiO.sub.2) of 100 nm is grown thermally on one side of the Si
substrate, while the backside of the substrate is covered with an
Al layer which acts as a gate electrode. An organic film is then
applied on top of the oxide.
[0160] This may be done by means of spin-coating a 1% w/v solution
of the precursor polymer (II) in chlorobenzene. Measurements of the
hole mobility are performed with FETs on which furthermore Au
source and drain electrodes are evaporated after the organic film
is applied. Before starting the measurement, the precursor polymer
(II) in the form of a thin film is converted to the insoluble
conjugated polymer poly(p-thienylene vinylene) (PTV) by heating the
sample from room temperature to 185.degree. C. at 2.degree. C. per
minute. After the sample is hold at 185.degree. C. for 10 minutes,
it is cooled back to ambient temperature.
[0161] A negative gate-voltage induces an accumulation of positive
charges in a thin conducting channel on the contact surface of the
organic film with the oxide. The field-effect mobilities are
determined from the saturation regime of the drain-source current
with the formula:
I.sub.ds,sat=.mu..sub.FEWC.sub.ox(V.sub.gs-V.sub.t).sup.2/2L
wherein W is the width and L the length of the conducting channel
respectively, C.sub.ox is the capacity of the isolating SiO.sub.2
layer, V.sub.gs is the gate voltage and V.sub.t is the threshold
voltage.
[0162] A bilayer organic heterojunction solar cell is prepared
according to the following procedure using the precursor polymer
synthesised in accordance with the method described in this
embodiment. Two ITO/PEDOT/PTV/AI devices on glass substrate were
tested.
[0163] A first test is carried out with a first device wherein
pristine is used an active layer. The second device is made by
first converting the spin-coated precursor and afterwards
spin-coating [6,6]-PCBM on top of it, thus forming a bilayer solar
cell. J/V curves of the devices in dark and under illumination of
100 mW/cm.sup.2 light from halogen lamp were studied. Experimental
results of both devices are summarized in table 3.
TABLE-US-00003 TABLE 3 Starting monomer with structural units of
formula (I) with: Ar = 2,5-thienylene, R.sub.0 = --NR.sub.1R.sub.2
with R.sub.1.ident.R.sub.2 = Et. Pristine Bilayer solar cell
J.sub.sc (mA/cm.sup.2) 430 1430 V.sub.oc (mV) 435 515 FF (%) 34
48.5 .eta. (%) 0.06 0.36
[0164] Organic heterojunction solar cells are prepared according to
the following procedure using the soluble precursor polymer
synthesised in accordance with the method described in this
embodiment. Glass substrates coated with ITO (resistance .about.90
ohm per square) are first cleaned with isopropanol in an ultrasonic
bath for 20 min and dried in a nitrogen flow. The samples are
brought into the glove box with a nitrogen atmosphere. All
following steps now are done inside the glove box. An 80 nm layer
of PEDOT/PSSA is spin-coated on top of the ITO and heat treated for
10 min at 180.degree. C. on a hot plate. Then, the sample is cooled
down to room temperature and thereafter the photoactive layer,
which is cast from a 0.5 wt.-% solution of precursor polymer of
formula (II) mixed with a soluble C.sub.60 derivative (PCBM) in
chlorobenzene, is spincoated on top of the PEDOT/PSSA. The ratio by
weight of the precursor polymer of formula (II) and PCBM is
comprised between 1:0.5 and 1:4. The solution is stirred with a
magnetic stirrer for 4 hours at room temperature.
[0165] The spincoating of the active layer is a two-step procedure.
The first step, to determine the thickness, is done with a closed
cover. The spinning speed is comprised between 250 rpm and 600 rpm
and the spinning time between 1 and 5 seconds. The second step is
to dry the film. This step is performed with an open cover for 3
min at 100 rpm. The converted film may have a thickness between 80
and 100 nm.
[0166] The conversion of the soluble precursor polymer, in the
example given blended with PCBM, is done on a hot plate inside the
glove box from room temperature up to 150.degree. C. with a
temperature step of 2.degree. C. per minute. Then, the temperature
is kept constant at 150.degree. C. for 5 min. This is the so-called
"Conversion reaction" done by heat treatment, here in thin film, in
which a soluble precursor polymer is chemically converted to the
related conjugated polymer, which might be soluble or insoluble, by
thermal induced elimination of the leaving groups and formation of
the vinylene double bonds. After that, the top electrode is
evaporated in a vacuum of 2.10.sup.-6 mbar. First, a 0.7 nm thick
layer of LiF and then a second layer of 150 nm aluminum are
evaporated. The active area of each cell is 6 mm.sup.2.
[0167] Afterwards, the sample is measured with a solar simulator
(AM1.5 spectrum). Then, a post-production heat treatment, also
called annealing treatment, on a hot plate took place for several
times, starting with 5 min at 70.degree. C. Then the samples are
measured again at room temperature and after that annealing process
again (55 min, in total 1 hour). Five annealing steps are done with
a total time of 9 hours. The results are much higher after 9 hours
of annealing than the initially values. The goal of the annealing
treatment, which is a heat treatment done on the level of the
conjugated polymer and not at the level of the precursor polymer,
is not a chemical reaction induced by heat but a heat relaxation
process of the conjugated polymer chains to release stress and
therefore induces a transformation of the conjugated polymer chains
morphology.
[0168] Example of results found for a Polymer/PCBM ratio of 1:1
with V.sub.oc=0.41V; J.sub.sc=3.42 mA/cm.sup.2; FF=34.4%;
.eta.=0.48%.
Example 3
[0169] A third example describes the synthesis of
thiophene-2,5-diylbismethylene N,N-diethyl
dithiocarbamate-3,4-diphenyl with a formula according to formula
(I) wherein Ar=3,4-diphenyl 2,5-thienylene and
R.sub.0=--NR.sub.1R.sub.2 with
R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5 followed by polymerisation
to the precursor polymer with a formula according to formula (II)
wherein Ar=3,4-diphenyl 2,5-thienylene and
R.sub.3.dbd.R.sub.4.dbd.H.
[0170] For the synthesis of 3,4-Diphenylthiophene, phenylboronic
acid (7.12 g, 58.394 mmol), 3,4-dibromothiophene (3.05 g, 12.603
mmol) and KF (2.92 g, 50.345 mmol) are dissolved in a mixture water
and toluene 50/50 (80 mL). Pd(PPh.sub.3).sub.4 (873 mg) is added as
a catalyst. After refluxing the mixture for 24 hours, an extraction
with CHCl.sub.3 (3.times.50 mL) is performed and the combined
organic phases are dried over MgSO.sub.4. The crude reaction
product is purified by column chromatography (silica, n-hexane).
The yield is 75%; .sup.1H NMR (CDCl.sub.3): 7.30 (s, 2H), 7.25-7.21
(m, 6H), 7.19-7.16 (m, 4H); MS (EI, m/e): 236 (M.sup.+)
[0171] For the synthesis of 3,4-Diphenyl-2,5-bis chloromethyl
thiophene concentrated HCl (4.93 g, 50.650 mmol) and acetic
anhydride (9.06 g, 88.859 mmol) are, under nitrogen atmosphere,
added to paraformaldehyde (719 mg, 23.992 mmol) and
3,4-diphenylthiophene (2.1 g, 8.886 mmol) in a three-necked flask.
After 4.5 hours refluxing this mixture at 70.degree. C., 10 mL of a
cold saturated aqueous solution of sodium acetate and 10 mL of a
25% aqueous solution of sodium hydroxide are added. The mixture is
then extracted with CHCl.sub.3 (3.times.50 mL) and dried over
MgSO.sub.4. The yield of the process is 98%. .sup.1H NMR
(CDCl.sub.3): 7.24-7.21 (m, 6H), 7.08-7.05 (m, 4H), 4.67 (s, 4H);
MS (EI, m/e): 332 (M.sup.+), 297 (M.sup.+-Cl), 261 (M.sup.+-2
Cl)
[0172] For the synthesis of
3,4-diphenylthiophene-2,5-diylbismethylene N,N-diethyl
dithiocarbamate a mixture of
3,4-diphenyl-2,5-bischloromethylthiophene (3 g, 8.890 mmol) and
sodium diethyldithiocarbamate trihydrate (4.6 g, 20.448 mmol) in 10
mL of methanol is stirred for three hours at room temperature. The
mixture is then extracted with CHCl.sub.3 (3.times.50 mL), dried
over MgSO.sub.4 and after the solvent is evaporated, 3.5 g (70%
yield) of dithiocarbamate monomer is obtained as a pink solid.
.sup.1H NMR (CDCl.sub.3): 7.24-7.14 (m, 6H), 7.03-7.00 (m, 4H),
4.62 (s, 4H), 4.01 (q, J=7.2 Hz, 4H), 3.69 (q, J=7.2 Hz, 4H), 1.26
(2t, J=7.2 Hz, 12H). .sup.13C NMR (CDCl.sub.3): 194.22, 141.14,
135.33, 133.39, 129.99, 127.82, 126.77, 49.31, 46.63, 35.82, 12.39,
11.43.
[0173] A solution of the synthesised monomer (400 mg, 0.716 mmol)
in dry THF (3.6 ml, 0.2 M) at -78.degree. C. (or room temperature
or 0.degree. C.) is degassed for 15 minutes by passing through a
continuous nitrogen flow. An equimolar LDA solution (360 .mu.L of a
2 M solution in THF/n-hexane) is then added in one go to the
stirred monomer solution. The mixture is kept at -78.degree. C. (or
room temperature or 0.degree. C.) for 90 minutes and the passing of
nitrogen is continued. After this, the solution is allowed to come
to 0.degree. C. or ethanol (6 ml) is added at -78.degree. C. to
stop the reaction (this is not necessary if the polymerisation is
performed at R.T or 0.degree. C.). The polymer is precipitated in
ice water (100 ml) and extracted with chloroform (3.times.60 ml).
The solvent of the combined organic layers is evaporated under
reduced pressure and a second precipitation is performed in MeOH.
The precursor polymer is collected and dried in vacuum. .sup.1H NMR
(CDCl.sub.3): 6.78-7.14 (br s, 4H), 5.00-5.30 (br s, 1H), 3.82-4.10
(br s, 2H), 3.51-3.78 (br s, 2H), 2.92-3.12 (br s, 2H), 1.04-1.34
(br t, 6H). .sup.13C NMR (CDCl.sub.3): 194.38, 138.07, 137.17,
129.35, 128.30, 56.92, 49.15, 46.68, 42.63, 12.58, 11.65.
TABLE-US-00004 TABLE 4 Starting monomer with structural units of
formula (I) wherein Ar = 3,4-diphenyl-2,5-thienylene, R.sub.0 =
--NR.sub.1R.sub.2 with R.sub.1.ident.R.sub.2 = Et in THF. Conc.
Polymerisation Yield Mw (g/mol) (M) temp. (.degree. C.) (%) in DMF
PD 0.2 0 30 50400 1.4 -78 60 29800 1.2 -78 to 0 50 24600 1.2
Example 4
[0174] In a fourth example, a co-polymerisation reaction between
p-xylene bis(N,N-diethyldithiocarbamate) (Formula (I) wherein Ar is
a thiophene ring and R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5 and
further denoted as A) and 2,5-bis[ethoxy(thiocarbonyl)
thiomethyl]thiophene (Formula (VI) wherein Ar is a thiophene ring,
R.sub.7.dbd.R.sub.8.dbd.H and Y=Z=SC(S)OEtEt, and further denoted
as B) is illustrated.
[0175] A solution of monomer p-xylene
bis(N,N-diethyldithiocarbamate) (375, 250, 125 mg respectively) and
monomer 2,5-bis[ethoxy(thiocarbonyl) thiomethyl]thiophene (108,
217, 325 mg respectively) in dry THF (6.16 ml, 0.2 M) at
-78.degree. C. is degassed for 1 hour by passing through a
continuous nitrogen flow. An equimolar LDA solution (616 .mu.l of a
2 M solution in THF) is added in one go to the stirred monomer
solution. The mixture is kept at -78.degree. C. for 90 minutes and
the passing of nitrogen is continued. After this, ethanol (6 ml) is
added at -78.degree. C. to stop the reaction. The polymer is
precipitated in ice water (100 ml) and extracted with chloroform
(3.times.60 ml). The solvent of the combined organic layers is
evaporated under reduced pressure and a second precipitation is
performed in a 1/1 mixture (100 ml) of diethyl ether and hexane at
0.degree. C. The polymer is collected and dried in vacuum.
[0176] Experiments are carried out at different ratios of A and B.
The results are summarised in table 5.
TABLE-US-00005 TABLE 5 Starting monomer as a mixture of monomer
with structural units of formula (I) wherein Ar = 2,5-thienylene,
R.sub.0 = --NR.sub.1R.sub.2 with R.sub.1.ident.R.sub.2 = Et, (A),
and of monomer with structural units of formula (VI) wherein Ar =
2,5-thienylene, R.sub.7.ident.R.sub.8.ident.H and
Y.ident.Z.ident.SC(S)OEtEt, (B) Yield Mw Molar Ratio A/B (%)
(g/mol) PD 100/0 57 94400 3.1 75/25 56 372600 13.3 50/50 69 309900
12.8 25/75 70 202700 10.3 0/100 50 137200 7.8
Example 5
[0177] In a fifth example, the synthesis of 2,5-bis(N,N-diethyl
dithiocarbamate)-1-(3,7-dimethyloctyloxy)-4-methoxybenzene with a
formula according to formula (I) wherein
Ar=1-(3,7-dimethyloctyloxy)-4-methoxy-2,5-phenylene,
R.sub.0=--NR.sub.1R.sub.2, R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5,
followed by the polymerisation to the soluble precursor polymer
with a formula according to formula (II) wherein
Ar=1-(3,7-dimethyloctyloxy)-4-methoxy-2,5-phenylene,
R.sub.3.dbd.R.sub.4.dbd.H, is illustrated.
[0178] To 50 ml of an ethanol solution of
2,5-bis(chloromethyl)-1-(3,7-diemthyloxtyloxy)-4-methoxybenzene (5
g, 13.889 mmol), diethyl dithiocarbamic acid sodium salt trihydrate
(7.19 g, 31.944 mmol) is added as a solid, after which the mixture
is stirred at ambient temperature for three hours. Then, water is
added and the desired monomer is extracted with ether (3.times.100
ml) and dried over MgSO.sub.4. Evaporation of the solvents yields
92% of the pure product as a white solid. .sup.1H NMR (CDCl.sub.3):
6.99 (s, 2H), 4.52 (s, 2H), 4.48 (s, 2H), 3.95 (m, 4H+2H), 3.74 (s,
3H), 3.64 (m, 4H), 1.60-1.85 (m, 2H), 1.38-1.58 (m, 2H), 1.21 (t,
12H), 1.05-1.30 (m, 6H), 0.88 (d, 3H), 0.81 (d, 6H); .sup.13C NMR
(CDCl.sub.3): 196.11, 195.99, 151.27, 150.90, 125.08, 124.42,
114.75, 113.86, 67.13, 56.19, 49.41, 49.34, 46.61, 39.22, 37.32,
36.83, 36.30, 29.79, 27.95, 24.69, 22.69, 22.59, 19.62, 12.42,
11.59
[0179] The polymerisation reaction is analogous to that described
in example 1. Polymerisation experiments are carried out at
different temperatures. The results are summarised in table 6.
TABLE-US-00006 TABLE 6 Starting monomer with structural units of
formula (I) wherein Ar =
1-(3,7-dimethyloctyloxy)-4-methoxy-2,5-phenylene, R.sub.0 =
--NR.sub.1R.sub.2 with R.sub.1.ident.R.sub.2.ident.C.sub.2H.sub.5
in THF Polymerisation Yield Mw (g/mol) PD temperature (%) (in DMF)
(in DMF) -78.degree. C. 54 3800 1.0 Room temperature 59 14900 2.8
69 18400 2.9 35.degree. C. 62 18900 2.9 65.degree. C. 39 37100
1.4
Example 6
[0180] A sixth example describes the synthesis of
pyridine-2,5-diylbismethylene N,N-diethyl dithiocarbamate with a
formula according to formula (I) wherein Ar=2,5-pyridine,
R.sub.0=--NR.sub.1R.sub.2, R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5,
followed by the polymerisation to the soluble precursor polymer
with a formula according to formula (II) wherein Ar=2,5-pyridine,
R.sub.3.dbd.R.sub.4.dbd.H.
[0181] The yield of the reaction is 82%. .sup.1H NMR (CDCl.sub.3):
8.54 (d, 1H), 7.86 (d, 1H), 7.63 (d, 1H), 4.88 (s, 2H), 4.56 (s,
2H), 4.00 (q, 4H), 3.72 (q, 4H), 1.26 (2t, 12H); MS (EI, m/e): 401
(M.sup.+), 285 (M.sup.+-C(S)NEt.sub.2), 148 (SC(S)NEt.sub.2), 116
(C(S)NEt.sub.2).
[0182] The polymerisation reaction is analogous to that described
in example 1. Polymerisation experiments are carried out at room
temperature and 35.degree. C. The results are summarised in table
7.
TABLE-US-00007 TABLE 7 Starting monomer with structural units of
formula (I) wherein Ar = 2,5-pyridine, R.sub.0 = --NR.sub.1R.sub.2
with R.sub.1.ident.R.sub.2.ident.C.sub.2H.sub.5 in THF
Polymerisation Yield Mw (g/mol) PD temperature (%) (in DMF) (in
DMF) Room temperature 43 14800 2.0 35.degree. C. 40 15800 2.1
Example 7
[0183] In a seventh example, the synthesis of
1,4-bis{2-[2-(2-methoxy-ethoxy)ethoxy]ethoxy}-2,5-diyl bismethylene
N,N-diethyl dithiocarbamate with a formula according to formula (I)
wherein
Ar=1,4-bis-(2-(2-(2-methoxy-ethoxy)-ethoxy)-ethoxy)-benzene,
R.sub.0=--NR.sub.1R.sub.2, R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5,
followed by the polymerisation to the soluble precursor polymer
with a formula according to formula (II) wherein
Ar=1,4-bis-(2-(2-(2-methoxy-ethoxy)-ethoxy)-ethoxy)-benzene,
R.sub.3.dbd.R.sub.4.dbd.H.
[0184] The yield of the reaction is 75%. .sup.1H NMR (CDCl.sub.3):
7.01 (s, 2H), 4.54 (s, 4H), 4.09 (t, 4H), 3.81 (t, 4H), 3.60-3.76
(m, 20H), 3.53 (m, 4H), 3.36 (s, 6H), 1.25 (t, 12H); .sup.13C N
MR(CDCl.sub.3): 195.80, 150.73, 125.30, 115.22, 71.84, 70.83,
70.63, 70.47, 69.69, 68.81, 58.95, 49.38, 46.56, 36.48, 12.41,
11.57; DIP MS (Cl, m/e): 725 (M.sup.+), 576
(M.sup.+-SC(S)NEt.sub.2).
[0185] The polymerisation reaction is analogous to that described
in example 1. .sup.1H NMR (CDCl.sub.3): 6.69-6.87 (br s, 2H),
5.56-5.76 (br s, 1H), 3.42-4.13 (m, 28H), 1.00-1.34 (br t, 6H)
TABLE-US-00008 TABLE 8 Starting monomer with structural units of
formula (I) wherein Ar =
1,4-bis(2-(2-(2-methoxy-ethoxy)ethoxy)-ethoxy)-benzene, R.sub.0 =
--NR.sub.1R.sub.2 with R.sub.1 = R.sub.2.ident.C.sub.2H.sub.5 in
THF Polymerisation Yield Mw (g/mol) PD temperature (%) (in DMF) (in
DMF) Room temperature 59 14900 2.8
Example 8
[0186] In an eighth example, the synthesis of
3,4-dichlorothiophene-2,5-diylbismethylene N,N-diethyl
dithiocarbamate with a formula according to formula (I) wherein
Ar=3,4-dichloro-2,5-thienylene, R.sub.0=--NR.sub.1R.sub.2,
R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5, followed by the
polymerisation to the soluble precursor polymer with a formula
according to formula (II) wherein Ar=3,4-dichloro-2,5-thienylene,
R.sub.3.dbd.R.sub.4.dbd.H, is illustrated.
[0187] The yield of the reaction is 94%; .sup.1H NMR (CDCl.sub.3):
4.71 (s, 4H), 4.00 (q, J=7.2 Hz, 4H), 3.69 (q, J=7.2 Hz, 4H), 1.26
(t, J=7.2 Hz, 12H); .sup.13C NMR (CDCl.sub.3): 193.58, 131.67,
122.65, 49.80, 46.84, 34.50, 12.52, 11.53; MS (EI, m/e): 326
(M.sup.+-SC(S)NEt.sub.2), 178 (M.sup.+-2 SC(S)NEt.sub.2), 148
(SC(S)NEt.sub.2), 116 (C(S)NEt.sub.2), 72 (NEt.sub.2).
[0188] The polymerisation reaction is analogous to that described
in example 1. .sup.1H NMR (CDCl.sub.3): 5.50-5.80 (br s, 1H),
3.85-4.08 (br q, 2H), 3.63-3.83 (br q, 2H), 3.32-3.51 (br s, 2H),
1.14-1.36 (br t, 6H)
[0189] In this example, polymerisation experiments are carried out
at room temperature and 35.degree. C. The results are summarised in
table 9.
TABLE-US-00009 TABLE 9 Starting monomer with structural units of
formula (I) wherein Ar = 3,4-dichloro-2,5thienylene, R.sub.0 =
--NR.sub.1R.sub.2 with R.sub.1.ident.R.sub.2.ident.C.sub.2H.sub.5
in THF Polymerisation Yield Mw (g/mol) PD temperature (%) (in DMF)
(in DMF) Room temperature 64 10400 1.8 35.degree. C. 76 18500
2.8
Example 9
[0190] In an ninth example, the synthesis of
naphthalene-1,4-diylbismethylene N,N-diethyl dithiocarbamate with a
formula according to formula (I) wherein Ar=1,4-naphthalene,
R.sub.0=--NR.sub.1R.sub.2, R.sub.1.dbd.R.sub.2.dbd.C.sub.2H.sub.5,
followed by the polymerisation to the soluble precursor polymer
with a formula according to formula (II) wherein
Ar=1,4-naphthalene, R.sub.3.dbd.R.sub.4.dbd.H, is illustrated. The
yield of the reaction is 89%; .sup.1H NMR (CDCl.sub.3): 8.10, (q,
2H), 7.585 (q, 2H), 7.51 (s, 2H), 4.94 (s, 4H), 4.05 (q, J=7.2 Hz,
4H), 3.66 (q, J=7.2 Hz, 4H), 1.29 (2t, J=7.2 Hz, 6H), 1.21 (2t,
J=7.2 Hz, 6H); .sup.13C NMR (CDCl.sub.3): 195.10, 132.21, 131.96,
127.93, 126.40, 124.86, 49.41, 46.70, 40.48, 12.42, 11.61; DIP MS
(EI, m/e): 302 (M.sup.+-SC(S)NEt.sub.2), 148 (SC(S)NEt.sub.2), 116
(C(S)NEt.sub.2). The polymerisation reaction is analogous to that
described in example 1. Polymerisation experiments are carried out
at room temperature and 35.degree. C. The results are summarised in
table 10.
TABLE-US-00010 TABLE 10 Starting monomer with structural units of
formula (I) wherein Ar = 1,4-naphtalene, R.sub.0 =
--NR.sub.1R.sub.2 with R.sub.1.ident.R.sub.2.ident.C.sub.2H.sub.5
in THF Polymerisation Yield Mw (g/mol) PD temperature (%) (in DMF)
(in DMF) Room temperature 80 14600 1.5 35.degree. C. 78 15900
1.7
[0191] It is to be understood that although preferred embodiments,
specific constructions and configurations, as well as materials,
have been discussed herein for devices according to the present
invention, various changes or modifications in form and detail may
be made without departing from the scope and spirit of this
invention.
* * * * *