U.S. patent application number 13/123344 was filed with the patent office on 2011-11-03 for dye comprising a chromophore to which an acyloin group is attached.
This patent application is currently assigned to Sony Corporation. Invention is credited to Gerda Fuhrmann, Gabriele Nelles, Markus Obermaier, Ameneh Bamedi Zilai.
Application Number | 20110265878 13/123344 |
Document ID | / |
Family ID | 42109956 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110265878 |
Kind Code |
A1 |
Fuhrmann; Gerda ; et
al. |
November 3, 2011 |
DYE COMPRISING A CHROMOPHORE TO WHICH AN ACYLOIN GROUP IS
ATTACHED
Abstract
The present invention relates to a dye comprising a chromophore
to which an acyloin group as anchoring group is attached, to a
method of synthesis of such dye, to an electronic device comprising
such dye and to the use of such dye.
Inventors: |
Fuhrmann; Gerda; (Stuttgart,
DE) ; Nelles; Gabriele; (Stuttgart, DE) ;
Zilai; Ameneh Bamedi; (Stuttgart, DE) ; Obermaier;
Markus; (Stuttgart, DE) |
Assignee: |
Sony Corporation
Tokyo
JP
|
Family ID: |
42109956 |
Appl. No.: |
13/123344 |
Filed: |
September 23, 2009 |
PCT Filed: |
September 23, 2009 |
PCT NO: |
PCT/EP2009/006888 |
371 Date: |
July 11, 2011 |
Current U.S.
Class: |
136/263 ;
204/157.6; 252/586; 252/62.2; 540/145; 546/174; 546/6; 548/180;
548/403; 548/427; 548/466; 548/490; 548/560; 564/307 |
Current CPC
Class: |
C09B 57/10 20130101;
C09B 57/007 20130101; H01L 51/0064 20130101; C09B 62/78 20130101;
C09B 47/08 20130101; Y02P 70/50 20151101; H01G 9/2059 20130101;
H01L 51/0086 20130101; H01G 9/2031 20130101; Y02E 10/542 20130101;
Y02P 70/521 20151101; C09B 57/00 20130101 |
Class at
Publication: |
136/263 ;
548/466; 548/427; 548/490; 546/174; 548/180; 564/307; 548/560;
546/6; 540/145; 548/403; 252/586; 252/62.2; 204/157.6 |
International
Class: |
H01L 51/46 20060101
H01L051/46; C07D 209/60 20060101 C07D209/60; C07D 209/12 20060101
C07D209/12; C07D 215/14 20060101 C07D215/14; B01J 19/08 20060101
B01J019/08; C07C 211/54 20060101 C07C211/54; C07D 207/335 20060101
C07D207/335; C07F 15/00 20060101 C07F015/00; G02B 5/23 20060101
G02B005/23; H01G 9/20 20060101 H01G009/20; C07D 409/10 20060101
C07D409/10; C07D 277/64 20060101 C07D277/64 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2008 |
EP |
08018743.8 |
Jun 22, 2009 |
EP |
09008155.5 |
Claims
1. A dye, comprising a chromophore to which an acyloin group is
attached, and represented by formula (1a) or (1b): ##STR00027##
wherein said chromophore is an organic or metal-organic compound
absorbing electromagnetic radiation in a range from 300-1200 nm, or
wherein A is selected from the group consisting of H, a cyclic
alkyl, an acyclic alkyl, a straight or branched chain moiety of
formula --(CH.sub.2).sub.n1--R,
--[(CR.dbd.CR).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(C.ident.C).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(CH.sub.2).sub.n1--X.sub.n2].sub.p--R, a halogen, moiety
comprising at least one heteroatom, a substituted phenyl, an
un-substituted phenyl, a substituted biphenyl, an unsubstituted
biphenyl, a substituted heteroaryl, an unsubstituted heteroaryl,
and a moiety forming a ring structure with said acyloin group,
wherein, at each occurrence and independently, n1 and n2=0-12,
p=0-6, wherein X is --CR.sub.2, O, S, NR, --CR, wherein R is
selected from the group consisting of H, a straight or branched
alkyl chain of formula --C.sub.nH.sub.2n+1, --COOR.sup.1,
--OR.sup.1, --SR.sup.1, --NR.sup.1.sub.2, F, Cl, Br, I, O, N,
NO.sub.2, CN, and CF.sub.3, wherein R.sup.1 is H or a straight or
branched alkyl chain of formula --C.sub.nH.sub.2n+1, or a
substituted or non-substituted phenyl or biphenyl, heteroaryl, and
n=0-12.
2. The dye of claim 1, represented by formula (2a), (2b), (2c),
(2d), (2e), (2f), (2g), (2h), (2i), or (2j) ##STR00028##
##STR00029## wherein Y, at each occurrence, is independently
--CR.sub.2, O, S, NR, or --CR.
3. The dye of claim 2, represented by formula 2d, 2e, 2f, or
2h.
4. The dye of claim 1, wherein said chromophore is selected from
the group consisting of moieties shown in group 3 ##STR00030##
##STR00031## or any combination of the moieties of group 3, wherein
said chromophore is linked to said acycloin group by any of the
C-atoms or X or Y or R within said chromophore, wherein Z is one or
more moieties which, at each occurrence, is independently selected
from the group consisting of H, a cyclic alkyl, an acyclic alkyl, a
straight or branched chain moiety of formula
--(CH.sub.2).sub.n1--R,
--[(CR.dbd.CR).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(C.ident.C).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(CH.sub.2).sub.n1--X.sub.n2].sub.p--R, a halogen, moiety
comprising at least one heteroatom, a substituted phenyl, an
unsubstituted phenyl, a substituted biphenyl, an unsubstituted
biphenyl, a substituted heteroaryl, and an unsubstituted
heteroaryl.
5. The dye of claim 4, represented by formula (5) ##STR00032##
wherein R.sub.11, R.sub.12, R.sub.13, at each occurrence, are
independently selected from the group consisting of H, a straight
or branched alkyl chain of formula --C.sub.nH.sub.2n+1,
--COOR.sup.1, --OR.sup.1, --SR.sup.1, --NR.sup.1.sub.2, F, Cl, Br,
I, O, N, NO.sub.2, CN, CF.sub.3, wherein R.sup.1 is H or any
straight or branched alkyl chain of formula --C.sub.nH.sub.2n+, or
any substituted or non-substituted phenyl or biphenyl, heteroaryl,
n=0-12.
6. The dye of claim 5, represented by formula (6) ##STR00033## or
represented by any of structures 17-26: ##STR00034##
##STR00035##
7. The dye of claim 5, represented by formula (7), (8), (9), (10),
(11), (12), or (13): ##STR00036## ##STR00037## ##STR00038##
##STR00039## ##STR00040## ##STR00041## ##STR00042##
8. The dye of claim 1, wherein said chromophore is a metal complex
selected from the group consisting of u structures represented by
formula (14) (L).sub.n3(L').sub.n4M(Hal).sub.n5 (14), wherein M is
Ruthenium Ru, Osmium Os, or Iridium Ir, Hal is independently Cl,
Br, I, CN, or --NCS, n3, n4, and n5 are integers which, at each
occurrence, are independently 0-4, and L and L' are organic
heterocyclic ligands comprising nitrogen atoms which are linked by
N-atoms to the respective metal M, and wherein either one of L and
L', or both L and L' are linked to the acyloin group by any of the
C-atoms within said ligands.
9. The dye of claim 8, wherein said ligands L and L' are
independently, at each occurrence, mono- or polycyclic, condensed
rings or such rings covalently bonded to each other.
10. The dye of claim 8, wherein said ligands L and L' are
independently, at each occurrence, selected from the group
consisting of ##STR00043## wherein Z is one or more moieties which,
at each occurrence, is independently selected from the group
consisting of H, a cyclic alkyl, an acyclic alkyl, a straight or
branched chain moiety of formula --(CH.sub.2).sub.n1--R,
--[(CR.dbd.CR).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(C.ident.C).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(CH.sub.2).sub.n1--X.sub.n2].sub.p--R, a halogen, a moiety
comprising at least one heteroatom, a substituted phenyl, an
unsubstituted phenyl, a substituted biphenyl, an unsubstituted
biphenyl, a substituted heteroaryl, and an unsubstituted
heteroaryl.
11. The dye of claim 1, wherein said chromophore is a metal complex
represented by formula (16), (IL'').sub.n6M' (16), wherein M' is
Palladium Pd, Platinum Pt or Nickel Ni, n6 being is an integer 0-4,
and L'' is an organic heterocyclic ligand comprising at least one
nitrogen atom, said ligand being linked by one or several of said
N-atoms to the respective metal M', and said ligand being linked to
said acycloin group by any of the C-atoms within said ligand.
12. The dye of claim 11, wherein said ligand L'' is selected from
the group consisting of ##STR00044## wherein Z is one or more
moieties which, at each occurrence, is independently selected from
the group consisting of H, a cyclic alkyl, an acyclic alkyl, a
straight or branched chain moiety of formula
--(CH.sub.2).sub.n1--R,
--[(CR.dbd.CR).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(C.ident.C).sub.n1--(CH.sub.2).sub.n2]--R,
--[(CH.sub.2).sub.n1--X.sub.n2].sub.p--R, a halogen, a moiety
comprising at least one heteroatom, a substituted phenyl, an
unsubstituted phenyl, a substituted biphenyl, an unsubstituted
biphenyl, a substituted heteroaryl, and an unsubstituted
heteroaryl.
13. An electronic device, comprising the dye of claim 1.
14. The device of claim 13, which is a solar cell further
comprising a photoactive semiconductor porous material.
15. The device of claim 13, further comprising a
charge-transporting agent which is a liquid, ionic liquid, polymer
gel based, or solid state electrolyte.
16. The device of claim 14, which is a solar cell wherein said dye
is chemisorbed to said photoactive semiconductor porous
material.
17. The device of claim 13, further comprising at least one other
dye.
18. The device according to claim 17, wherein said at least one
other dye is represented by formula (1c) or (1b).
19. The device of claim 17, wherein said at least one other dye
selected from the group consisting of structures 15 and 27-32:
##STR00045## ##STR00046##
20. The device of claim 14, wherein said photoactive semiconductor
porous material is at least one selected from the group consisting
of TiO.sub.2, SnO.sub.2, ZnO, Nb.sub.2O.sub.5, ZrO.sub.2,
CeO.sub.2, WO.sub.3, Cr.sub.2O.sub.3, CrO.sub.2, CrO.sub.3,
SiO.sub.2, Fe.sub.2O.sub.3, CuO, Al.sub.2O.sub.3, CuAlO.sub.2,
SrTiO.sub.3, SrCu.sub.2O.sub.2, and ZrTiO.sub.4.
21. The device of claim 20, wherein said photoactive semiconductor
porous material has one or several of the following features: a
thickness of 1-100 .mu.m, consists of one or more layers comprises
particles having an average diameter or length in a range of from 1
nm to 40 nm, is a mixture of at least a first particle and second
particle, said first particle having an average diameter or length
in a range of from 1 nm to 30 nm, and said second particle having
an average diameter in a range of from 30 nm to 100 nm and/or a
length in a range of from 100 nm to 5 .mu.m.
22. A dye-sensitized solar cell comprising a sensitizer comprising
the dye of claim 1.
23. The dye-sensitized solar cell of claim 22, further comprising
at least one other dye.
24. The dye-sensitized solar cell of claim 23, wherein said at
least one other dye is represented by formula (1a) or (1b) or a dye
selected from structures 15, 27-32: ##STR00047## ##STR00048##
25. A method of photocatalyzing a reaction, the method comprising:
exposing a component of the reaction to light in the pressure of
the dye of claim 1.
26. The dye of claim 1, wherein the chromophore absorbs
electromagnetic radiation in a range from 350-500 nm.
27. The dye of claim 1, wherein the chromophore absorbs
electromagnetic radiation in a range from 500-750 nm.
28. The dye of claim 4, wherein at least one Z of the chromophore
is a moiety of group 4: ##STR00049##
Description
[0001] The present invention relates to a dye comprising a
chromophore to which an acyloin group is attached, to a method of
synthesis of such dye, to an electronic device comprising such dye
and to the use of such dye.
[0002] The dye-sensitised solar cell (DSSC) (B. O'Regan and M.
Gratzel, Nature 353 (1991) 737; WO 91/16719 [A]) is a photovoltaic
device that offers high energy-conversion efficiencies at low cost.
In contrast to the silicon-based systems, where the semiconductor
assumes both the task of light absorption and charge carrier
transport, in DSSCs these functions are separated. Light is
absorbed by a sensitizer dye which is anchored to the surface of a
semiconductor such as nanocrystalline TiO.sub.2. The charge
separation takes place at the interface via photo-induced electron
injection from the dye into the conduction band of the
semiconductor. The dye molecule is regenerated from a counter
electrode via a redox couple in the electrolyte. The redox couple
is regenerated in turn at the counter-electrode the circuit being
completed by electron transport through the external load.
[0003] The efficiency of a DSSC is determined by the number of
collected and injected photons, and thus by the light absorbed by
the dye sensitizer. One of the main criteria of a dye to act as
efficient sensitizer in DSSC is its adsorbtion (by chemisorption)
onto the semiconductor surface. Further, for high efficiencies, the
ideal sensitizer should absorb efficiently over a broad range of
solar spectrum. Upon photo-excitation the dye should inject
electrons into the conduction band of the semiconductor with a
quantum yield of unity. To minimize energy losses during electron
transfer, the energy level of its excited state should be well
matched with the lower bound of the conduction band of the
semiconductor. Its redox potential should be well matched with that
of the redox couple so that the dye regeneration via electron
donation is possible.
[0004] The best photovoltaic performance has so far been achieved
with carboxyl groups containing polypyridyl complexes of ruthenium
(known as red-dye and black-dye). [M. K. Nazeeruddin, A. Kay, I.
Rodicio, R. Humphry-Baker, E. Muller, P. Liska, N. Vlachoppoulos,
M. Gratzel, J. Am. Chem. Soc., 1993, 115, 6382]. The
photoexcitation of a Ru-complex results in an intramolecular
metal-to-ligand charge-transfer (MLCT) transition. The photoexcited
electrons located in the bipyridyl ligands can be very efficiently
injected in the conduction band of the semiconductor via the
carboxyl-anchor groups. This process has been shown to be very
fast. [Y. Tachibana, J. E. Moser, M. Gratzel, D. R. Klug, J. R.
Durrant, J. Phys. Chem. 1996, 100, 20056] In contrast, for these
complexes the recombination process between the injected electrons
in TiO.sub.2 and the dye-cations is a slow process. The slow
recombination is considered to be a result of the large separation
between semiconductor and the Ru.sup.3+ by the bipyridyl ligands.
Thus, the molecular design of these Ru-complexes is successful in
an efficient charge separation and thus, high energy conversion
efficiency.
[0005] However, the energy conversion efficiency of the DSSC is
limited by the light-harvesting capacity of these Ru-dyes to absorb
the sunlight. The photo-active region of the photovoltaic device is
reduced to the visible part of the solar spectrum, and within that,
to the shorter wavelength region. The photons of the longer
wavelength region are not harvested and cannot be converted to
electrical energy.
[0006] So far most of the dyes employed as photosensitizers in the
field of DSSC have as anchoring group carboxylic acid groups to
anchor on to nanoporous semiconductor. This limits the pool of all
dyes, organic, inorganic and hybrid that can be used as sensitizer.
Other anchoring group which show good properties and have been more
intensively studied are phosphonic acid groups (a) Gratzel et al,
J. Phys. Chem. B, 2004, 108, 17553; b) W. Choi et al, J. Physl.
Chem. B, 2006, 110, 14792-14799). Adsorption and charge injection
could be further demonstrated with other anchoring groups like
sulfonic acid, hydroxyl, triethoxysilane, catechol group and
boronic acid, but no solar cells with significant efficiency of
DSSC could be achieved with dyes having such anchoring groups (a)
Gratzel et al, New. J. Chem., 2000, 24, 651-652; b) Ford et al., J.
Phys. Chem. B, 1994, 98, 3822; c) Lakhimiri et al., J. Photochem.
Photobiol., A, 2004, 166, 91.).
[0007] Nanoporous semiconductors, such as TiO.sub.2, are key
components in the process of heteregenous photocatalysis applied in
the field of photocatalytic hydrogen production or photolytic water
purification (Arakawa et al., J. Photochem. Photobiol. A, 2000,
63-69; b) Chanon, Eds. Elsevier, Photoinduced Electron Transfer,
1988). Most photocatalysts, such as nanoiporous TiO.sub.2, are
active under UV irradiation, and their inactivity in the visible
light region (solar light) limits their practical application. One
of the strategies to overcome this is the anchoring of charge
transfer dyes to the surface of the wide band gap semiconductor
rendering them sensitive to visible sun light. As above, the dyes
are generally linked to the semiconductor through a carboxylate
linkages via a ester linkage. This linkage is quite unstable in
water which is the environment in such processes. There is a need
on alternative effective and stable anchoring groups for attaching
dyes on the semiconductor surfaces.
[0008] Accordingly, it was an object of the present invention to
provide for improved dyes with intense absorption in the visible
and long wavelength region of the solar spectrum. It was another
object of the present invention to provide for dyes which can be
easily covalently attached to nanocrystalline wide band gap
semiconductors, such as TiO.sub.2, SnO.sub.2 etc. It was
furthermore an object of the present invention to provide for dyes
that allow an efficient charge transfer from the dye to the
semiconductor. It was furthermore an object of the present
invention to provide for dyes that are easily accessible due simple
methods of preparation.
[0009] All these objects are solved by a dye comprising a
chromophore to which an acyloin group is attached, said dye being
represented by formula 1a or 1b:
##STR00001##
wherein said chromophore is an organic or metal-organic compound
absorbing electromagnetic radiation in the range from 300-1200 nm,
or a subrange thereof, preferably 350-500 nm or 500-750 nm or
350-700 nm, wherein A is selected from H, or any cyclic or acyclic
alkyl, or any straight or branched chain moiety of general formula
--(CH.sub.2).sub.n1--R,
--[(CR.dbd.CR).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(C.ident.C).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(CH.sub.2).sub.n1--X.sub.n2].sub.p--R, or halogen, such as F,
Cl, Br, I, or moieties containing heteroatoms, such as NO.sub.2,
CN, NR.sub.2, --OH or any substituted or non-substituted phenyl or
biphenyl or heteroaryl, or moieties forming a ring structure with
said acyloin group, wherein, at each occurrence and independently,
n1 and n2=0-12, preferably 0-4, p=0-6, preferably 0-2, wherein X is
selected from --CR.sub.2, O, S, NR, --CR, wherein R is selected
from H or any straight or branched alkyl chain of general formula
--C.sub.nH.sub.2n+1, or --COOR.sup.1, --OR.sup.1, --SR',
--NR.sup.1.sub.2, or F, Cl, Br, I, O, N, NO.sub.2, CN, CF.sub.3,
wherein R.sup.1 is H or any straight or branched alkyl chain of
general formula --C.sub.nH.sub.2n+1, or any substituted or
non-substituted phenyl or biphenyl, heteroaryl, n=0-12, preferably
0-6.
[0010] In one embodiment, the dye according to the present
invention comprises a chromophore to which an acyloin group is
attached, said dye being represented by formula 2a, 2b, 2c, 2d, 2e,
2f, 2g, 2h, 2i, or 2j
##STR00002## ##STR00003##
wherein A, X, n1, n2, n, p are as defined above, and wherein Y, at
each occurrence, is independently selected from --CR.sub.2, O, S,
NR, --CR, R being as defined above.
[0011] In one embodiment, the dye according to the present
invention is represented by formula 2d, 2e, 2f, or 2h
[0012] In one embodiment, said chromophore is selected from the
moieties shown in formula 3
##STR00004## ##STR00005##
or any combination of the moieties represented by formula 3,
wherein said chromophore is linked to said acycloin group by any of
the C-atoms or X or Y or R within said chromophore, wherein Z is
one or more moieties which, at each occurrence, is independently
selected from H, or any cyclic or acyclic alkyl, or any straight or
branched chain moiety of general formula --(CH.sub.2).sub.n1--R,
--[(CR.dbd.CR).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(C.ident.C).sub.n1--(CH.sub.2).sub.n2].sub.p--R,
--[(CH.sub.2).sub.n1--X.sub.n2].sub.p--R, or halogen, such as F,
Cl, Br, I, or moieties containing heteroatoms, such as NO.sub.2,
CN, NR.sub.2, --OH or any substituted or non-substituted phenyl or
biphenyl or heteroaryl, preferably represented by formula 4
##STR00006##
and wherein R, X, Y, n, n.sub.1, n.sub.2 and p are as defined in
claim 1.
[0013] In one embodiment, the dye according to the present
invention is represented by formula 5
##STR00007##
wherein R.sub.11, R.sub.12, R.sub.13, at each occurrence, are
independently selected from H or any straight or branched alkyl
chain of general formula --C.sub.nH.sub.2n+1, or --COOR.sup.1,
--OR.sup.1, --SR.sup.1, --NR.sup.1.sub.2, or F, Cl, Br, I, O, N,
NO.sub.2, CN, CF.sub.3, wherein R.sup.1 is H or any straight or
branched alkyl chain of general formula --C.sub.nH.sub.2+1 or any
substituted or non-substituted phenyl or biphenyl, heteroaryl,
n=0-12 preferably 0-6, and wherein X and Z are as defined in claim
4.
[0014] In one embodiment, the dye according to the present
invention is represented by formula 6
##STR00008##
or is represented by any of structures 17-26:
##STR00009## ##STR00010##
[0015] In one embodiment, the dye according to the present
invention is represented by formula 7
##STR00011##
wherein R.sub.11, Z, and X are as defined in claim 5, or is
represented by formula 8
##STR00012##
wherein R.sub.11, R.sub.12, R.sub.13, Z, X and Y are as defined
above, or is represented by formula 9
##STR00013##
wherein R.sub.11, Z, X and Y are as defined above, or is
represented by formula 10
##STR00014##
wherein R, Z, X and n are as defined above, or is represented by
formula 11
##STR00015##
wherein R, Z, X, Y and n are as defined above, or is represented by
formula 12
##STR00016##
wherein R, Z, Y, X and n are as defined above, or is represented by
formula 13
##STR00017##
wherein R, Z, X, Y, n are as defined above.
[0016] In one embodiment, said chromophore is a metal complex
selected from the structures represented by formula 14
(L).sub.n3(L').sub.n4M(Hal).sub.n5 (formula 14)
M being Ruthenium Ru, Osmium Os, or Iridium Ir, preferably
Ruthenium, Hal being independently selected from Cl, Br, I, CN,
--NCS, preferably --NCS with n3, n4, n5 being integers which, at
each occurrence, are independently 0-4, preferably 2 or 3, and L
and L' being organic heterocyclic ligands containing nitrogen atoms
which are linked by N-atoms to the respective metal M, and wherein
either one of L and L', or both L and L' are linked to the acyloin
group by any of the C-atoms within said ligands.
[0017] In one embodiment, said ligands L and L' are independently,
at each occurrence, mono- or polycyclic, condensed rings or such
rings covalently bonded to each other.
[0018] In one embodiment, said ligands L and U are independently,
at each occurrence, selected from the group comprising
##STR00018##
wherein Z is as defined above.
[0019] In one embodiment, said chromophore is a metal complex
represented by formula 16
(L'').sub.n6M' (formula 16)
M' being Palladium Pd, Platinum Pt or Nickel Ni, preferably Pd, and
n6 being an integer 0-4, preferably 1-2, and L'' being an organic
heterocyclic ligand containing nitrogen atoms, said ligand being
linked by one or several of said N-atoms to the respective metal
M', and said ligand being linked to said acycloin group by any of
the C-atoms within said ligand.
[0020] In one embodiment, said ligand L'' is selected from the
group comprising
##STR00019##
wherein Z is as defined above.
[0021] The objects of the present invention are also solved by an
electronic device comprising a dye as defined above.
[0022] In one embodiment, the device according to the present
invention is a solar cell, preferably a dye-sensitized solar cell
(DSSC), said solar cell further comprising a photoactive
semiconductor porous material.
[0023] In one embodiment, the device according to the present
invention contains a charge-transporting agent which is a liquid,
polymer gel based or solid state electrolyte.
[0024] In one embodiment, the device according to the present
invention is a solar cell wherein said dye is chemisorbed to said
photoactive semiconductor porous material.
[0025] In one embodiment, the device according to the present
invention further comprises at least one other dye.
[0026] In one embodiment, said at least one other dye is a dye
according to the present invention.
[0027] In one embodiment, said at least one other dye is a dye
selected from structures 15, 27-32:
##STR00020## ##STR00021## ##STR00022##
[0028] In one embodiment, said photoactive semiconductor porous
material is selected from TiO.sub.2, SnO.sub.2, ZnO,
Nb.sub.2O.sub.5, ZrO.sub.2, CeO.sub.2, WO.sub.3, Cr.sub.2O.sub.3,
CrO.sub.2, CrO.sub.3, SiO.sub.2, Fe.sub.2O.sub.3, CuO,
Al.sub.2O.sub.3, CuAlO.sub.2, SrTiO.sub.3, SrCu.sub.2O.sub.2,
ZrTiO.sub.4, preferably TiO.sub.2, and combinations of the
foregoing.
[0029] In one embodiment, said photoactive semiconductor porous
material has one or several of the following features: [0030] a
thickness of 1-100 .mu.m, preferably 5-30 .mu.m, [0031] consists of
one or more layers [0032] contains particles having an average
diameter or length in the range of from 1 nm to 40 nm, preferably
15-30 nm [0033] is a mixture of at least a first and second kind of
particles, said first kind of particles having an average diameter
or length in the range of from 1 nm to 30 nm, and said second kind
of particles having an average diameter in the range of from 30 nm
to 100 nm and/or a length in the range of from 100 nm to 5
.mu.M.
[0034] The objects of the present invention are also solved by the
use of a dye according to the present invention as a sensitizer in
a dye-sensitized solar cell.
[0035] In one embodiment, said use is together with at least one
other dye.
[0036] In one embodiment, said at least one other dye is a dye as
defined above, or a dye selected from structures 15, 27-32:
##STR00023## ##STR00024## ##STR00025##
[0037] In one embodiment, said use together with at least one other
dye is in a dye-sensitized solar cell having a tandem geometry (as,
e.g., described in Example 9 below), or the mixture of a dye in
accordance with the present invention and at least one other dye is
used for coating an electrode of said dye-sensitized solar
cell.
[0038] The objects of the present invention are also solved by the
use of a dye according to the present invention, as a
photosensitzer in a photocatalytic process, such as photocatalysed
hydrogen production or photocatalytic degradation of organic
pollutants. It should be noted that any photocatalytic process may
be useful in the context of the present invention.
[0039] In one embodiment, during preparation of the device, the dye
molecules are adsorbed to the nanoporous particles via
self-assembling out of a dye solution or a dyes-mixture
solution.
[0040] Examples of electronic devices comprising a dye in
accordance with the present invention include energy supply devices
for portable electronic devices and displays, such as solar cell
panels for or incorporated in mobile phones, notebooks, laptops,
portable audio-tape players, MP3-players, remote controls, e-cards,
e-books, e-readers, portable CD-players, portable DVD-players,
cameras, digicams, GPS devices, portable sensors, displays
integrated in electronic devices. Examples of electronic devices in
accordance with the present invention also include portable solar
chargers for batteries of any of the afore-mentioned devices.
Moreover, electronic devices in accordance with the present
invention include smart windows, on-roof-applications, especially
in areas where a grid connection is not possible, e.g. camping
cars, boats. If the electronic device in accordance with the
present invention is an energy supply device, and said energy
supply device is a solar cell panel, such panel is preferably a
dye-sensitized solar cell panel (DSSC panel) (see also FIG.
21).
[0041] The objects of the present invention are also solved by the
use of a dye according to the present invention, for the
sensitization of the photocatalyst, such as TiO.sub.2, in
photocatalytic processes, e.g in photocatalysed hydrogen
production, photocatalytic splitting of water or photocatalytic
decomposition of pollutants.
[0042] As used herein, the term "dye" is meant to refer to a
chromophore to which an acyloin group is attached. The term
"chromophore", as used herein, is meant to refer to an organic or
metal-organic compound which is able to absorb electromagnetic
radiation in the range of from 350 nm to 1100 nm, or a subrange
thereof, e.g 350-500 nm or 500-850 nm, or 350-850 nm.
[0043] An acyloin group is the moiety which is included in the
structure of the dyes according to present invention and is
represented by formula 18
##STR00026##
[0044] The term "anchoring group", as used herein, is meant to
refer to any functional group that allows a covalent coupling
(chemisorption) of the entity to which such anchoring group
belongs, to a surface, for example the surface of a nanoporous
semiconductor layer within a solar cell.
[0045] A dye is referred to as being "chemisorbed" to a layer or
surface, if the dye is covalently coupled thereto.
[0046] With reference to formula 3 which exemplifies a
"chromophore" in accordance with the present invention, the term "a
combination of the moieties represented by formula 3" is used. This
is meant to encompass any molecule wherein one or several of the
structures given in formula 3 are covalently linked to each other
to also produce a "chromophore".
[0047] The term "substituted phenyl/biphenyl" is meant to refer to
any phenyl/biphenyl wherein a hydrogen has been replaced by a
substituent, such as a halogen, NO.sub.2, NH.sub.2, OH or other
suitable functional groups. Such substituents have for example been
defined above as Z, which substituents may also be substitutents at
a phenyl or biphenyl.
[0048] The inventors have surprisingly found that using acyloin
groups as anchoring groups for a dye allows an efficient covalent
attachment of such dye to nanoporous surfaces of photoactive
layers, such as TiO.sub.2-layers. The dyes having the acyloin group
attached as anchoring group can be used as sensitizers in solar
cells but also for sensitizing the photocatalyst which are mosly
wide band gap oxide semiconductors such as TiO.sub.2, to extend the
photocatalytic activity of the photocatalysts into the visible
light region. This is particular important for example in the field
of heterogeneous photocatalysis such as photolytic hydrogen
production or photocatylytic water production or photocatalytic
destruction of organic pollutants. In using the approach in
accordance with the present invention, the number of dyes that can
be potentially used in such applications is strongly increased.
Moreover, the synthesis of such dyes is surprisingly simple.
[0049] The dyes according to the present invention show high
quantum efficiency similar to that of the standard red-dye. If one
therefore combines the dyes of the present invention with other
dyes, such as other organic dyes or standard red dye or standard
black dye, a broad range of the solar spectrum may be harvested.
That makes the dyes of the present invention very promising to be
used together with other dyes, such as organic dyes, standard red
dye or standard black dye or further dyes according to the present
invention with absorption maxima at different wavelengths. A dye
sensitized solar cell comprising a dye according to the present
invention, and, in addition thereto, one or more further dyes, is
herein also referred to as a multiple-dyes sensitized solar cell
(M-DSSC). Preferably, said one or more further dyes is also a dye
according to the present invention.
[0050] Further, organic dyes have high absorption coefficients.
This means it needs less amount of dye to absorb the same amount of
light. Less amount of one dye on a surface enables the use of more
dyes with different absorption properties, ideally being a mixture
of dyes absorbing the whole range of the sun spectrum.
[0051] Furthermore, reference is made to the figures, wherein
[0052] FIG. 1 shows a synthesis scheme of one example dye in
accordance with the present invention being represented by general
formula 2e, E being Cl or an alkoxy group, preferably ethoxy,
propoxy, iso-propoxy or butoxy, X being as defined above,
chromophore being as defined above,
[0053] FIG. 2 shows a synthesis scheme of one example dye in
accordance with the present invention being represented by general
formula 2h, E, Y, X, n.sub.1, n.sub.2, p, chromophore being as
defined above, Hal.sup.- being I.sup.-, Cl.sup.-, Br.sup.-,
NCS.sup.- or SCN.sup.-,
[0054] FIG. 3 shows a synthesis scheme of one example dye in
accordance with the present invention being represented by general
formula 5, E, Z, R.sub.11-R.sub.13, X being as defined above,
[0055] FIG. 4 shows a synthesis scheme of one example dye in
accordance with the present invention being represented by general
formula 9, X, Y, Z, R.sub.1 being as defined above,
[0056] FIG. 5 shows the molecular structure of some dyes according
to present invention,
[0057] FIG. 6 shows the synthesis of one example dye in accordance
with the present invention being represented by formula 1,
[0058] FIG. 7 shows the synthesis of one example dye in accordance
with the present invention being represented by formula 2,
[0059] FIG. 8 shows the synthesis of one example dye in accordance
with the present invention being represented by formula 5,
[0060] FIG. 9 shows a photograph of the adsorption of dye in
accordance with the present invention being represented by formula
1 on a TiO.sub.2 layer,
[0061] FIG. 10 shows a table indicating the performance of a dye
sensitized solar cell prepared with a dye in accordance with the
present invention being represented by formula 1 by measuring the
efficiency of solar cells by means of sulphur lamp,
[0062] FIG. 11 shows the incident photon to current efficiency
(IPCE) plotted against wavelength for a dye in accordance with the
present invention being represented by formula 1,
[0063] FIG. 12 shows a table displaying the performance of various
dye sensitized solar cells prepared with a dye in accordance with
the present invention being represented by formula 1 in mixture
with other dyes and in comparison to other sensitizers,
[0064] FIG. 13 shows the incident photon to current efficiency of a
dye in accordance with the present invention being represented by
formula 1, of a dye being represented by formula 14 (FIG. 15) and a
mixture of these two dyes, plotted against wavelength,
[0065] FIG. 14 shows a table indicating the performance of a dye
sensitized solar cell prepared with a dye in accordance with the
present invention being represented by formula 1 in comparison with
organic dye being represented by formula 16 (FIG. 15), by measuring
the efficiency of solar cells by means of sun simulator,
[0066] FIG. 15 shows the structure of other sensitizers that were
used for comparison and in mixture with dyes according to present
invention (sensitizers 14, 15 and 16).
[0067] FIG. 16 shows structures 17-26 which are exemplary dyes in
accordance with the present invention.
[0068] FIG. 17 shows exemplary structures 15, 27-32 of other dyes
which can be used together with the dyes in accordance with the
present invention.
[0069] FIGS. 18-20 show various tables and IPCE curves showing the
efficiencies of solar cells, as prepared and described in Examples
11) to 13).
[0070] FIG. 21 shows various embodiments of electronic devices in
accordance with the present invention wherein energy supply
devices, such as solar cell panels, preferably dye sensitized solar
cell panels (DSSCs) have been incorporated.
[0071] Moreover reference is made to the following examples which
are given to illustrate, not to limit the present invention.
EXAMPLES
1) Synthesis of One Embodiment of a Dye in Accordance with the
Present Invention, in this Case Dye 1
[0072] FIG. 6 shows the synthesis scheme of dye 1 in accordance
with the present invention.
[0073] An equimolar amount of 1a and diethylester derivative of
squaric acid 1b in ethanol is heated in presence of small amount
triethylamine to 70.degree. C. for 4 h. The solvent is removed and
the crude product is purified by column chromatography on silica
gel with n-hexane/ethylacetate as eluent to yield the pure product
1c.
[0074] In next step, to derivative 1c in ethanol aqueous NaOH is
added and the mixture stirred for 2 h at 50.degree. C. After
cooling, aq. HCl is added and the solvent is removed. The crude
product is purified by column chromatography on silica gel with
dichloromethane/methanol as eluent. The dye 1 in accordance with
the present invention is isolated as yellow solid.
2) Synthesis of One Embodiment of a Dye in Accordance with the
Present Invention, in this Case Dye 2
[0075] FIG. 7 shows the synthesis scheme of dye 2 in accordance
with the present invention.
[0076] An equimolar amount of 2a and diethylester derivative of
squaric acid 1b in ethanol and in presence of small amount
triethylamine is heated to 80.degree. C. for 6 h. The solvent is
removed and the crude product is purified by column chromatography
on silica gel with n-hexane/ethylacetate as eluent to yield the
pure intermediate 2b.
[0077] In next step, to 2b in ethanol aqueous NaOH is added and the
mixture stirred for 2 h at 50.degree. C. After cooling, aq. HCl is
added and the solvent is removed. The crude product is purified by
column chromatography on silica gel with dichloromethane/methanol
as eluent. The dye 2 in accordance with the present invention is
isolated as yellow-orange solid.
3) Synthesis of One Embodiment of a Dye in Accordance with the
Present Invention, in this Case Dye 5
[0078] FIG. 8 shows the synthesis scheme of dye 5 in accordance
with the present invention.
[0079] An equimolar amount of brominated derivative 5a and
diethylester derivative of squaric acid 1b in ethanol and in
presence of small amount triethylamine is heated to 80.degree. C.
for 6 h. The solvent is removed and the crude product is purified
by column chromatography on silica gel with n-hexane/ethylacetate
as eluent to yield the pure intermediate 5b.
[0080] In a next step, to a mixture of 5b in of toluene/methanol,
1.2 equivalents of thienyl boronic acid, 1 mol % Pd-catalyst, 10
equivalents K.sub.2CO.sub.3 are added. The mixture is allowed to
stir at 120.degree. C. for 12 h. After cooling the solvent is
evaporated. The crude product is purified by column chromatography
on silica gel with n-hexane/ethylacetate as eluent to yield pure
5c.
[0081] In a subsequent reaction to 5c in ethanol, aqueous NaOH is
added and the mixture stirred for 2 h at 50.degree. C. After
cooling, aq. HCl is added and the solvent is removed. The crude
product is purified by column chromatography on silica gel with
dichloromethane/methanol as eluent. The pure dye 5 in accordance
with the present invention is isolated as orange solid.
4) Analytical Data of Dye 1
[0082] C18H19NO3 (297.36)
[0083] .sup.1H NMR (400 MHz, MeOD): .delta.=14.8 (s, 1H, --OH),
7.27-7.20 (m, 2H, arH), 6.98-6.92 (m, 2H, arH), 5.70 (s, 1H,
.dbd.CH--), 3.95 (t, 2H, N--CH2), 1.84-1.75 (m, 2H, CH2-Pr), 1.65
(s, 6H, arCH3), 1.06 (t, 6H, CH3-Pr)
[0084] ESI MS m/z=297.8 [M+].
[0085] UV/VIS (acetonitrile): .lamda.max=404 nm.
5) Effective Adsorption of the Dye on TiO2
[0086] FIG. 9 shows a photograph of the adsorption of dye 1 in
accordance with the present invention on a TiO.sub.2 layer
[0087] For device preparation, the substrate with screen printed
nanoporous TiO2 particles is poured and kept in a dye or dyes
mixture solution for at least 1 h. The dye molecules having the
acyloin group as anchor group are able to adsorb onto the
nanoporous layer via self-assembling. The effective adsorption and
chemisorption (covalent coupling) of the dyes with acyloin group
onto semiconductor surface is proved by the stable color of the
substrate even after the substrate was washed with an organic
solvent.
6) General Protocol for Preparing Solar Cells
[0088] The DSSCs are assembled as follows: A 30-nm-thick bulk
TiO.sub.2 blocking layer is formed on FTO (approx. 100 nm on glass
or flexible substrate). A 5-30 .mu.m-thick porous layer of
TiO.sub.2 semiconductor particles of 0.1882 cm.sup.2 active area
multi-printed by screen printing on the blocking layer and sintered
at 450.degree. C. for half an hour. Dye molecules are adsorbed to
the nanoporos particles via self-assembling out of a dye-solution.
The dye-solution consists of a single dye or single dye and an
additive, such as deoxycholic acid or a mixture of dye in different
ratio or a mixture of dye in different ratio and an additive. The
porous layer is filled with liquid electrolyte containing
I.sup.-/I.sub.3.sup.- as redox couple (15 mM) by drop casting. A
reflective platinum back electrode is attached with a distance of 6
.mu.m from the porous layer.
7) Measuring the Efficiency of DSSCS Containing at Least One of the
Sensitizer Dye Produced by the Method of the Present Invention
[0089] The quality of the cells is evaluated by means of current
density (J) and voltage (V) characteristics under illumination with
light from
[0090] a) a sulphur lamp (IKL Celsius, Light Drive 1000) with an
intensity of 100 mW cm.sup.2. If not otherwise stated, the results
are averages over three cells.
[0091] b) a sun simulator (AM1.5G YSS-150) with an intensity of 100
mW cm.sup.-2.
[0092] If not otherwise stated, the results are averages over three
cells.
[0093] The efficiency of a photovoltaic device is calculated as
follows:
.eta.=P.sub.out/P.sub.in=FF.times.(J.sub.SC.times.V.sub.OC)/(L.times.A)
with FF=V.sub.max.times.I.sub.max/V.sub.oc.times.I.sub.sc FF=fill
factor V.sub.OC=open circuit voltage J.sub.SC=short current density
L=intensity of illumination=100 mW/cm.sup.2 A=active area=0.24
cm.sup.2 V.sub.max=voltage at maximum power point J.sub.max=current
at maximum power point
[0094] An important parameter for judging the performance of a dye
as sensitizer in DSSC is the IPCE curve. The IPCE curve reflects
the photo-activity of the sensitizer dyes at different wavelengths
(IPCE=incident photon to current efficiency).
[0095] The respective structure of the dyes is given in FIGS. 5 and
15.
8) Efficiency of the DSSC by Using Dye 1 as Sensitizer
[0096] The performance and the efficiency of DSSCs prepared by
method described in 6 and measured by method described in 7a with
dye 1 are shown in FIG. 10. FIG. 11 shows the IPCE plotted verses
wavelength for sensitizer 1.
[0097] The efficiency of the DSSC prepared with sensitizer dye 1
shows high efficiency (>7%). There are only few other organic
dyes, such as dye 16, showing such high performance. However, the
superiority of the dyes according to present invention lies not
only in the high efficiencies of the DSSCs achieved when using
these dyes, but also in their simple preparation (FIGS. 1-4).
[0098] The highest achievable IPCE value is 1.0. Sensitizer dye 1
shows an IPCE value of 0.9 in its maximum at ca. 490 nm. That means
that the photons absorbed in this region from the sun can be
converted to almost 90% to current by injection into conduction
band of TiO.sub.2. Such a high value is rarely achieved and only
with few dyes, such as the Ruthenium based standard red dye.
9) Efficiency of M-DSSC Containing a Mixture of Dye 1 and the
Organic Dye 14, and a Mixture of Dye 1 and Standard Black Dye
15
[0099] The solar cells were prepared by method described in Example
6 and measured according to Example 7a. For comparison also DSSCs
prepared with the respective single sensitizer dye were prepared
and measured.
[0100] The performance and the efficiency of DSSCs are shown in
FIG. 12.
[0101] A mixture of the dye in accordance with the present
invention, in this case dye 1, with either an organic dye 14 or
with a Ruthenium based dye (black dye) 15 yields an increase in
short current density and thus, a drastic increase in DSSC
efficiency.
[0102] FIG. 13 shows the IPCE curve of the individual dyes 1 and
14, and the IPCE curve of a 1:1 mixture of these dyes. The
individual dyes are photo-active in different region of the solar
spectrum. By using a mixture of the dyes, due to additive behaviour
of the IPCE curves, a very broad range solar light can be harvested
and converted to current.
10) Comparing Efficiency of the DSSC Prepared with Dye According to
Present Invention, Namely Dye 1, and Another Organic Sensitizer 16
Both Harvesting Light in the Same Range of the Solar Spectrum
[0103] The DSSCs were prepared by method described in Example 6 and
measured according to Example 7b.
[0104] The DSSC efficiencies are in the same range of 5%. However,
when one compares the structure of the dyes, it becomes clear that
the dye according to present invention, namely dye 1, is much more
easily synthesized than dye 16.
11) Efficiency of the DSSC by Using Dye 9 and 2 as Sensitizer
[0105] The DSSCs were prepared by the method described in Example 6
and by using 25 .mu.m TiO.sub.2 layer and measured according to
Example 7b. The efficiency and IPCE curve are shown in FIGS. 18a
and 18b, respectively.
[0106] The IPCE curve reflects the photo-activity of the sensitizer
dyes at different wavelengths (IPCE=incident photon to current
efficiency). The highest achievable IPCE value is 1.0. Sensitizer
dye 1, 9 and 2 show very high, of almost unity, and wide IPCE
values.
12) Performance of Solar Cells Prepared with a Mixture of the
Respective Dye and Standard Ruthenium Black Dye 15
[0107] The solar cells were prepared by method described in Example
6 and measured according to Example 7b. For comparison also DSSC
prepared with the respective single sensitizer dye 15 was prepared
and measured. The efficiency is shown in FIG. 19. As can be seen,
the efficiencies by using a mixture of dyes for sensitization are
much higher than that using only a single dye as sensitizer.
13) Performance of Solar Cells Prepared with a Mixture of the
Respective Dye and Organic Dye 14
[0108] The solar cells were prepared by method described in Example
6 and measured according to Example 7b. For comparison also DSSC
prepared with the respective single sensitizer dye 14 was prepared
and measured. [0109] a) by using 26 .mu.m TiO.sub.2 layers as
electrode; the efficiency is shown in FIG. 20a. [0110] b) by using
10 .mu.m TiO.sub.2 layers as electrode; the efficiency is shown in
FIG. 20b.
[0111] The efficiencies on thinner layer are slightly lower than on
thick TiO2 layer, but, contrary to Ruthenium based sensitizers,
still high enough to show the good performance of the dyes. This is
attributed to the strong light absorption property of the dyes
according to claim 1-12. In both cases, thin or thick TiO2 layers,
the efficiency is increased by using a mixture of dyes for
sensitization compared to that using a single dye.
[0112] The present invention provides for new sensitizer dyes which
are useful for being employed in solar cells as well as in
photocatalytic applications. They readily adsorb to nanoporous
semiconductor layers and are easily manufactured. The use of an
acyloin group as anchoring group for chromophores in such
applications, to the best knowledge of the present inventors, has
never been reported before.
[0113] The features of the present invention disclosed in the
specification, the claims and/or in the accompanying drawings, may,
both separately, and in any combination thereof, be material for
realizing the invention in various forms thereof.
* * * * *