U.S. patent application number 16/955826 was filed with the patent office on 2020-10-29 for coordination complex and electronic device comprising the same.
The applicant listed for this patent is Novaled GmbH. Invention is credited to Ulrich Heggemann, Markus Hummert, Thomas Rosenow, Ulrike Schliebe.
Application Number | 20200343460 16/955826 |
Document ID | / |
Family ID | 1000004985340 |
Filed Date | 2020-10-29 |
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United States Patent
Application |
20200343460 |
Kind Code |
A1 |
Hummert; Markus ; et
al. |
October 29, 2020 |
Coordination Complex and Electronic Device Comprising the Same
Abstract
The present invention relates to an electronic device comprising
a hole injection layer and/or a hole transport layer and/or a hole
generating layer, wherein at least one of the hole injection layer,
the hole transport layer and the hole generating layer comprises a
coordination complex comprising at least one electropositive atom M
having an electronegativity value according to Allen of less than
2.4 and at least one ligand L having the following structure: (I)
wherein R.sup.1 and R.sup.2 are independently selected from the
group, consisting of C.sub.1 to C.sub.30 hydrocarbyl groups and
C.sub.2 to C.sub.30 heterocyclic groups, wherein R.sup.1 and/or
R.sup.2 may optionally be substituted with at least one of CN, F,
Cl, Br and I. ##STR00001##
Inventors: |
Hummert; Markus; (Dresden,
DE) ; Heggemann; Ulrich; (Dresden, DE) ;
Rosenow; Thomas; (Dresden, DE) ; Schliebe;
Ulrike; (Dresden, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Novaled GmbH |
Dresden |
|
DE |
|
|
Family ID: |
1000004985340 |
Appl. No.: |
16/955826 |
Filed: |
December 20, 2018 |
PCT Filed: |
December 20, 2018 |
PCT NO: |
PCT/EP2018/086085 |
371 Date: |
June 19, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 51/0028 20130101;
H01L 51/5088 20130101; H01L 51/0092 20130101; H01L 51/506 20130101;
H01L 51/0077 20130101; C07F 3/02 20130101; C07F 13/005 20130101;
H01L 51/56 20130101; C07F 3/06 20130101; H01L 51/0084 20130101 |
International
Class: |
H01L 51/00 20060101
H01L051/00; C07F 3/06 20060101 C07F003/06; C07F 13/00 20060101
C07F013/00; C07F 3/02 20060101 C07F003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2017 |
EP |
17209023.5 |
Claims
1. Electronic device comprising a hole injection layer and/or a
hole transport layer and/or a hole generating layer, wherein at
least one of the hole injection layer, the hole transport layer and
the hole generating layer comprises a coordination complex
comprising at least one electropositive atom M having an
electro-negativity value according to Allen of less than 2.4 and at
least one ligand L having the following structure: ##STR00032##
wherein R.sup.1 and R.sup.2 are independently selected from the
group consisting of C.sub.1 to C.sub.30 hydrocarbyl groups and
C.sub.2 to C.sub.30 heterocyclic groups, wherein R.sup.1 and/or
R.sup.2 may optionally be substituted with at least one of CN, F,
Cl, Br and I.
2. Electronic device according to claim 1 wherein the coordination
complex has the general formula (I) M.sub.nL.sub.mQ.sub.pO.sub.l
(I) wherein Q is a ligand different from L; n is from 1 to 4; m is
from 1 to 6; p is from 0 to 6; and 1 is 0 or 1.
3. Electronic device according to claim 1, wherein M is selected
from metals forming divalent and/or trivalent cations.
4. Electronic device according to claim 1, wherein R.sup.1 and/or
R.sup.2 are substituted with substituents selected from the group
consisting of CN, F, Cl, Br, and I and in at least one of R.sup.1
and R.sup.2 the number ratio of substituents:hydrogen is
.gtoreq.1.
5. Electronic device according to claim 2, wherein m is 2 to 4.
6. Electronic device according to claim 1, wherein the coordination
complex is an inverse coordination complex comprising (i) a core
consisting of one atom or a plurality of atoms forming a covalent
cluster; and (ii) a first coordination sphere consisting of at
least four electropositive atoms M, wherein all core atoms have a
higher electronegativity according to Allen than any of the
electropositive atoms M in the first coordination sphere, and the
at least one ligand L is coordinated to at least one atom of the
first coordination sphere.
7. Coordination complex having the general formula (I) ##STR00033##
wherein M is an electropositive atom having an electro-negativity
value according to Allen of less than 2.4; n is 1 and m is 2 or 3;
and R.sup.1 and R.sup.2 are independently selected from the group
consisting of C.sub.1 to C.sub.30 hydrocarbyl and C.sub.2 to
C.sub.30 heterocyclic group, wherein R.sup.1 and R.sup.2 are each
substituted with substituents selected from the group consisting of
CN, F, Cl, Br and I and the ratio of substituents:hydrogen in each
of the R.sup.1 and R.sup.2 is .gtoreq.1.
8. Coordination complex comprising (i) a core consisting of one
atom or a plurality of atoms forming a covalent cluster; (ii) a
first coordination sphere consisting of at least four
electropositive atoms M; and (iii) a second coordination sphere
comprising a plurality of ligands, wherein the first coordination
sphere is closer to the core than the second coordination sphere,
all core atoms have a higher electronegativity according to Allen
than any of the electropositive atoms comprised in the first
coordination sphere, the ligands of the second coordination sphere
are coordinated to the electropositive atoms of the first
coordination sphere, and at least one ligand L of the plurality of
ligands of the second coordination sphere has the following
structure ##STR00034## wherein R.sup.1 and R.sup.2 are
independently selected from the group consisting of C.sub.1 to
C.sub.30 hydrocarbyl groups and C.sub.2 to C.sub.30 heterocyclic
groups, wherein R.sup.1 and/or R.sup.2 may optionally be
substituted with at least one of CN, F, Cl, Br and I.
9. Method for preparing the coordination complex according to claim
8, the method comprising: heating a complex having the general
formula ML.sub.2.
10. Method for preparing an electronic device according to claim 1,
comprising a step of heating the coordination complex.
11. Method according to claim 10, further comprising the steps of
(ii) vaporizing the coordination complex according to general
formula (I); and (iii) depositing the vapor of the coordination
complex on a solid support.
12. Method according to claim 11, wherein the vaporizing and the
depositing respectively comprise co-vaporizing and co-deposition of
the coordination complex with a matrix material.
13. Electronic device obtainable by the method according to claim
10.
14. Semiconducting material comprising a hole transport matrix
material and a p-dopant which is the coordination complex as
defined in claim 1 or the coordination complex according to claim
7.
15. Solid crystalline phase consisting of a compound having the
chemical formula C.sub.42F.sub.48N.sub.6O.sub.13S.sub.6Zn.sub.4.
Description
[0001] The present invention relates to an electronic device
comprising a coordination complex, the respective coordination
complex, a method for preparing the same, a semiconducting material
comprising the coordination complex and a solid crystalline phase
consisting of the coordination complex.
BACKGROUND ART
[0002] Organic light-emitting diodes (OLEDs), which are
self-emitting devices, have a wide viewing angle, excellent
contrast, quick response, high brightness, excellent driving
voltage characteristics, and color reproduction. A typical OLED
includes an anode, a hole transport layer (HTL), an emission layer
(EML), an electron transport layer (ETL), and a cathode, which are
sequentially stacked on a substrate. In this regard, the HTL, the
EML, and the ETL are thin films formed from organic and/or
organometallic compounds.
[0003] When a voltage is applied to the anode and the cathode,
holes injected from the anode electrode move to the EML, via the
HTL, and electrons injected from the cathode electrode move to the
EML, via the ETL. The holes and electrons recombine in the EML to
generate excitons. When the excitons drop from an excited state to
a ground state, light is emitted. The injection and flow of holes
and electrons should be balanced, so that an OLED having the
above-described structure has excellent efficiency.
[0004] Organic electronic devices comprising
trifluoromethansulfonimide (TFSI) metal complexes are known in the
art. Furthermore, for example, U.S. Pat. No. 6,528,137 B1 discloses
sulfonylamide complexes for use in the emitting layer or an
electron transport layer of an organic light emitting diode.
[0005] However, there is still a need to improve the performance of
electronic devices, in particular to select suitable materials to
be comprised in organic hole transport layers, organic hole
injection layers or hole generating materials helpful to improve
the performance of a respective electronic device.
[0006] It is, therefore, the object of the present invention to
provide an electronic device and a method for preparing the same
overcoming drawbacks of the prior art, in particular to provide
electronic devices comprising an organic hole transport material,
an organic hole injection material or a hole generating material,
the electronic devices having improved performance, in particular
reduced operational voltage and/or improved efficiency, in
particular in OLEDs.
SUMMARY OF THE INVENTION
[0007] The above object is achieved by an electronic device
comprising a hole injection layer and/or a hole transport layer
and/or a hole generating layer, wherein at least one of the hole
injection layer, the hole transport layer and the hole generating
layer comprises a coordination complex comprising at least one
electropositive atom M having an electro-negativity value according
to Allen of less than 2.4 and at least one ligand L having the
following structure:
##STR00002##
[0008] wherein R.sup.1 and R.sup.2 are independently selected from
the group, consisting of C.sub.1 to C.sub.30 hydrocarbyl groups and
C.sub.2 to C.sub.30 heterocyclic groups, wherein R.sup.1 and/or
R.sup.2 may optionally be substituted with at least one of CN, F,
Cl, Br and I.
[0009] It was surprisingly found by the inventors that an
electronic device comprising a coordination complex as defined
above in a hole injection layer, a hole transport layer or a hole
generating layer thereof shows superior properties over devices of
the prior art, in particular with respect to operational voltage
and quantum efficiency. Further advantages are apparent from the
specific examples presented herein.
[0010] In the inventive electronic device, the coordination complex
may have the general formula (I)
M.sub.nL.sub.mQ.sub.pO.sub.l (I),
[0011] wherein Q is a ligand different from L; n is from 1 to 4; m
is from 1 to 6; p is from 0 to 6; and 1 is 0 or 1. Respective
choices allow fine tuning of the electronic structure of the
inventive coordination complex to improve the usability thereof in
hole injection layers, hole transport layers or hole generating
layers of electronic devices.
[0012] In the electronic device, M may be selected from metals
forming divalent and/or trivalent cations. In this regard, the term
"forming divalent and/or trivalent cations" refers to the formation
of cations which are stable under standard conditions.
[0013] More specifically, it is to be understood that a metal
forming a divalent cation is an element having electronegativity
according to Allen of less than 2.4, which is known to occur in
oxidation state (+II) in at least one compound which is at the
temperature 25.degree. C. thermodynamically and/or kinetically
stable enough that it could be prepared and the oxidation state
(+III) for the element could be proven. Analogously, it is to be
understood that a metal forming a trivalent cation is an element
having electronegativity according to Allen of less than 2.4, which
is known to occur in oxidation state (+III) in at least one
compound which is at the temperature 25.degree. C.
thermodynamically and/or kinetically stable enough that it could be
prepared and the oxidation state (+III) for the element could be
proven. As typical elements forming divalent cations can be
considered elements of the second and twelfth group of the Periodic
Table, transition metals, Sn and Pb. As typical elements forming
trivalent cations can be considered elements of the third and
thirteenth group of the Periodic Table, inner transition metals, Sb
and Bi. Respective choices allow fine tuning of the electronic
structure of the inventive coordination complex to improve the
usability thereof in hole injection layers, hole transport layers
or hole generating layers of electronic devices.
[0014] M may be selected from metals forming divalent cations.
Respective choices allow fine tuning of the electronic structure of
the inventive coordination complex to improve the usability thereof
in hole injection layers, hole transport layers or hole generating
layers of electronic devices.
[0015] M may be selected from the group consisting of Ti, Cr, Mn,
Fe, Co, Ni, Zn, and Cu. Respective choices allow fine tuning of the
electronic structure of the inventive coordination complex to
improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0016] M may be selected from the group consisting of Mn, Fe, Co,
Ni, and Zn. Respective choices allow fine tuning of the electronic
structure of the inventive coordination complex to improve the
usability thereof in hole injection layers, hole transport layers
or hole generating layers of electronic devices.
[0017] In the inventive electronic device R.sup.1 and/or R.sup.2
may be substituted with substituents selected from the group
consisting of CN, F, Cl, Br, and I and in at least one of R.sup.1
and R.sup.2 the number ratio of substituents:hydrogen is .gtoreq.1;
alternatively .gtoreq.2, alternatively .gtoreq.3; alternatively
.gtoreq.4; alternatively .gtoreq.9. Respective choices allow fine
tuning of the electronic structure of the inventive coordination
complex to improve the usability thereof in hole injection layers,
hole transport layers or hole generating layers of electronic
devices.
[0018] In the inventive electronic device, both R.sup.1 and/or
R.sup.2 may be substituted with substituents selected from the
group consisting of CN, F, Cl, Br, and I, wherein in each of
R.sup.1 and R.sup.2 the number ratio of substituents:hydrogen is
.gtoreq.1; alternatively .gtoreq.2, alternatively .gtoreq..sub.3;
alternatively .gtoreq..sub.4; alternatively .gtoreq..sub.9.
Respective choices allow fine tuning of the electronic structure of
the inventive coordination complex to improve the usability thereof
in hole injection layers, hole transport layers or hole generating
layers of electronic devices.
[0019] In the inventive electronic device R.sup.1 and/or R.sup.2
may be fully substituted with substituents selected from the group
consisting of CN, F, Cl, Br and I. Respective choices allow fine
tuning of the electronic structure of the inventive coordination
complex to improve the usability thereof in hole injection layers,
hole transport layers or hole generating layers of electronic
devices.
[0020] In the inventive electronic device R.sup.1 and/or R.sup.2
may be perhalogenated. Respective choices allow fine tuning of the
electronic structure of the inventive coordination complex to
improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0021] In the inventive electronic device R.sup.1 and/or R.sup.2
may be perfluorinated. Respective choices allow fine tuning of the
electronic structure of the inventive coordination complex to
improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0022] In the inventive electronic device R.sup.1 may be selected
from saturated hydrocarbyl groups; alternatively halogenated alkyl
groups or halogenated cycloalkyl groups; alternatively
perhalogenated alkyl groups or perhalogenated cycloalkyl groups;
alternatively perfluorinated alkyl groups or perfluorinated
cycloalkyl groups. Respective choices allow fine tuning of the
electronic structure of the inventive coordination complex to
improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0023] In the inventive electronic device R.sup.2 may be selected
from the group consisting of C.sub.6 to C.sub.30 aromatic groups
and C.sub.2 to C.sub.30 heteroaromatic groups, wherein R.sup.2 may
optionally be substituted with one or more halogen atoms;
alternatively R.sup.2 is selected from perhalogenated C.sub.6 to
C.sub.30 aromatic groups or perhalogenated C.sub.2 to C.sub.30
heteroaromatic groups, alternatively R.sup.2 is selected from
perfluorinated C.sub.6 to C.sub.30 aromatic groups or C.sub.2 to
C.sub.30 heteroaromatic groups. Respective choices allow fine
tuning of the electronic structure of the inventive coordination
complex to improve the usability thereof in hole injection layers,
hole transport layers or hole generating layers of electronic
devices.
[0024] In the inventive electronic device m may be 2; alternatively
n is 3; alternatively n is 4. Respective choices allow fine tuning
of the electronic structure of the inventive coordination complex
to improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0025] In the inventive electronic device the coordination complex
may be an inverse coordination complex comprising (i) a core
consisting of one atom or a plurality of atoms forming a covalent
cluster; and (ii) a first coordination sphere consisting of at
least four electropositive atoms M, wherein all core atoms have a
higher electronegativity according to Allen than any of the
electropositive atoms M in the first coordination sphere, and the
at least one ligand L is coordinated to at least one atom of the
first coordination sphere. Respective choices allow fine timing of
the electronic structure of the inventive coordination complex to
improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0026] This coordination complex having the three features (i) to
(iii) and the structure described above is referred herein as an
"inverse coordination complex". With regard to interatomic
interaction which is typically mirrored by equilibrium distance
between the interacting atoms, the relationship between the core
and the first coordination sphere in inverse coordination complexes
is the same as in normal coordination complexes. In other words, in
couples of closest atoms of the entire complex, wherein the first
atom of the couple belongs to the core and the second atom of the
couple belongs to the first coordination sphere, the distance
between the first and the second atom is equal to or shorter than
the sum of van der Waals radii of the first and of the second atom.
The term "inverse" encompasses the circumstance that whereas in
normal complexes an electropositive central atom is surrounded by
more electronegative atoms of respective ligands, in inverse
coordination complexes, the electronegative atoms of the core are
surrounded by more electropositive atoms of the first coordination
sphere.
[0027] The inverse coordination complex may be electrically
neutral.
[0028] In the inverse coordination complex, the electropositive
atoms may independently be selected from elements having an
electronegativity according to Allen which is lower than 2.4,
alternative lower than 2.3, alternatively lower than 2.2,
alternatively lower than 2.1, alternatively lower than 2.0,
alternatively lower than 1.9.
[0029] The electropositive atoms may independently be selected from
metal atoms in the oxidation state (II), alternatively from
transition metals of the fourth period of the periodic table of
elements in the oxidation state (II), alternatively from Ti, Cr,
Mn, Fe, Co, Ni, Zn, and Co in the oxidation state (II),
alternatively from Mn, Fe, Co, Ni, Zn respectively in the oxidation
state (II), alternatively are Zn (II).
[0030] In the inverse coordination complex the core may consist of
atoms having an electronegativity according to Allen higher than
1.7, alternatively higher than 1.8, alternatively higher than 1.9,
alternatively higher than 2.0, alternatively higher than 2.1,
alternatively higher than 2.2, alternatively higher than 2.3 and
alternatively higher than 2.4.
[0031] In the inverse coordination complex, the core may consist of
one atom in a negative oxidation state, alternatively of a
chalcogen atom in the oxidation state (-II), alternatively
chalcogen atoms which may be selected from O, S, Se and Te in the
oxidation state (-II), alternatively from O (-II) and S (-II),
alternatively the core is a single O (-II) atom.
[0032] In the inverse coordination complex, the first coordination
sphere may consist of four metal atoms in the oxidation state (II)
tetrahedrally coordinated to the core.
[0033] In the inverse coordination complex, the second coordination
sphere may consist of a plurality of ligands having the structure
L.
[0034] In the inverse coordination complex, at least one ligand L
of the second coordination sphere may be coordinated to two
different metal atoms of the first coordination sphere.
[0035] In the inverse coordination complex, the core may consist of
one chalcogen atom selected from O, S, Se and Te in the oxidation
state (-II), the first oxidation sphere may consist of four metal
atoms in the oxidation state (II) tetrahedrally coordinated to the
core and the second coordination sphere may consist of six ands
having the structure L.
[0036] In the inverse coordination complex, each ligand L may be
coordinated to two different metal atoms of the first coordination
sphere.
[0037] In the inverse coordination complex, the N-atom, the S-atom
and one of the O-atoms of the sulfonylamide group of each ligand L
may form with two metal atoms M and M' of the first coordination
sphere and with one core atom X a six-membered ring having the
following formula (Ia)
##STR00003##
[0038] In the inverse coordination complex, R.sup.1 and R.sup.2 be
as defined as above.
[0039] In all of the foregoing embodiments with respect to the
inverse coordination complex, each respective selection may be
helpful for fine tuning of the electronic structure of the inverse
coordination complex to improve the usability thereof in organic
semiconducting layers of organic electronic devices.
[0040] the object is further achieved by a method for preparing the
inventive inverse coordination complex the method comprising
heating a complex having the general formula (ML.sub.2).
[0041] The inventive method for preparing the inventive
coordination complex may comprise evaporation of the complex under
reduced pressure.
[0042] The method the comprise a step of depositing the evaporated
complex on a solid support.
[0043] The object is further achieved by a coordination complex
having the general formula (I)
##STR00004##
[0044] wherein n is 1 and m is 2 or 3;
[0045] wherein R.sup.1 and R.sup.2 are independently selected from
the group consisting of C.sub.1 to C.sub.30 hydrocarbyl and C.sub.2
to C.sub.30 heterocyclic group, wherein R.sup.1 and R.sup.2 are
each substituted with substituents selected from the group
consisting of CN, F, Cl, Br and I and the ratio of
substituents:hydrogen in each of the R.sup.1 and R.sup.2 is
.gtoreq.1.
[0046] It was surprisingly found by the inventors that a respective
coordination complex is suitable to improve the performance of
electronic and devices when being used therein, in particular in
the hole transport/hole injection or hole generation part
thereof.
[0047] In the inventive coordination complex, the ratio of
substituents:hydrogen in each of the R.sup.1 and R.sup.2 may be
.gtoreq.2; alternatively .gtoreq.3; alternatively .gtoreq.4;
alternatively .gtoreq.9. Respective choices allow fine tuning of
the electronic structure of the inventive coordination complex to
improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0048] In the inventive coordination complex, R.sup.1 and/or
R.sup.2 may be fully substituted with substituents independently
selected from CN, F, Cl, Br and/or I. Respective choices allow fine
tuning of the electronic structure of the inventive coordination
complex to improve the usability thereof in hole injection layers,
hole transport layers or hole generating layers of electronic
devices.
[0049] In the inventive coordination complex, R.sup.1 and/or
R.sup.2 may be perhalogenated. Respective choices allow fine tuning
of the electronic structure of the inventive coordination complex
to improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0050] In the inventive coordination complex, R.sup.1 and/or
R.sup.2 may be perfluorinated. Respective choices allow fine tuning
of the electronic structure of the inventive coordination complex
to improve the usability thereof in hole injection layers, hole
transport layers or hole generating layers of electronic
devices.
[0051] In the inventive coordination complex, m may be 2.
Respective choices allow fine tuning of the electronic structure of
the inventive coordination complex to improve the usability thereof
in hole injection layers, hole transport layers or hole generating
layers of electronic devices.
[0052] In the inventive coordination complex, M may be selected
from the group consisting of Ti, Cr, Mn, Fe, Co, Ni, Zn, and Cu.
Respective choices allow fine tuning of the electronic structure of
the inventive coordination complex to improve the usability thereof
in hole injection layers, hole transport layers or hole generating
layers of electronic devices.
[0053] In the inventive coordination complex, M may be selected
from the group consisting of Mn, Fe, Co, Ni, and Zn; alternatively
M may be Zn. Respective choices allow fine tuning of the electronic
structure of the inventive coordination complex to improve the
usability thereof in hole injection layers, hole transport layers
or hole generating layers of electronic devices.
[0054] The object is further achieved by a method for preparing an
inventive electronic device comprising a step of heating the
coordination complex as defined above.
[0055] The method for preparing the electronic device may further
comprise the steps of [0056] (ii) vaporizing the coordination
complex; and [0057] (iii) depositing the vapor of the coordination
complex on a solid support.
[0058] Furthermore, the vaporizing and the depositing may
respectively comprise co-vaporizing and compositing of the
coordination complex with a matrix material.
[0059] The object is further achieved by an electronic device
obtainable by the inventive method for preparing an electronic
device. This embodiment of the invention mirrors the fact that
composition and/or structure of the coordination complexes
comprising at least one sulfonylamide ligand L may change during
heating of the complex and especially during its vaporization, as
demonstrated below on the example of compounds E2 and E3.
[0060] Furthermore, the object is achieved by a semiconducting
material comprising a hole transport material and a p-dopant which
is the coordination complex as defined above or the inverse
coordination complex defined above.
[0061] Furthermore, the object is achieved by a solid crystalline
phase consisting of a compound E3 having the chemical formula
C.sub.42F.sub.48N.sub.6O.sub.13S.sub.6Zn.sub.4.
[0062] The solid crystalline phase y have a monoclinic crystal
lattice belonging to the space group P1211.
[0063] At temperature 296.15 K, the solid c me phase may have the
following unit cell dimensions: [0064] a=14.1358 (5) .ANG.,
.alpha.=90.degree.; b=16.0291 (6) .ANG., .beta.=113.2920 (10);
c=15.9888 (6) .ANG.; .gamma.=90.degree..
[0065] In the solid crystalline phase, the number of molecules
having the chemical formula
C.sub.42F.sub.48N.sub.6O.sub.13S.sub.6Zn.sub.4 and comprised in the
unit cell of the crystal lattice may be Z=2.
[0066] In the solid crystalline phase, the unit cell volume at
temperature 296.15 K, may be 3327.6 (2) .ANG..sup.3 and calculated
density may be 2.158 g/cm.sup.3.
[0067] Finally, the object is achieved by a solid crystalline phase
consisting of a compound E5 having the chemical form
C.sub.54H.sub.18F.sub.54N.sub.6O.sub.1S.sub.6Zn.sub.4.
[0068] The solid crystalline phase may have a monoclinic crystal
lattice belonging to the space group P 21/c.
[0069] At temperature 170 K, the solid crystalline phase may have
the following it cell dimensions: [0070] a=15.5665 (3) .ANG.,
.alpha.=90.degree.; b=18.1036 (4) .ANG., .beta.=100.610 (1);
c=29.0763 (6) .ANG.; .gamma.=90.degree..
[0071] In the solid line phase, the number of molecules having the
chemical formula
C.sub.54H.sub.18F.sub.54N.sub.6O.sub.13S.sub.6Zn.sub.4 and
comprised in the unit cell of the crystal lattice may be Z=4.
[0072] In the solid crystalline phase, the unit cell volume at
temperature 170 K may be 8053.9 (3) .ANG..sup.3 and calculated
density may be 2.011 g/cm.sup.3.
[0073] In accordance with the invention, it may be provided that
coordination complexes having the composition ML.sub.nwith n being
1, 2 or 3, L being a ligand having the structure L above and
R.sup.2 being a heterocyclic group comprising a trivalent hetero
atom selected from N, P and As or a divalent hetero atom selected
from O, S, Se or Te are excluded from the scope of the
invention.
[0074] Alternatively, metal complexes may be excluded from the
invention, wherein the metal complexes have a composition ML.sub.n,
wherein n is 1, 2 or 3 and L is a ligand having the above structure
L with R.sup.2 being a heterocyclic group comprising the trivalent
or divalent heteroatom in such position that the heteroatom
coordinates to the M atom of the complex to form a 5-, 6- or
7-membered chelate ring. Alternatively, said metal complexes with
n=2 may be excluded from the scope of the invention. Alternatively,
said metal complexes may be excluded in which M is Zn.
Alternatively, said metal complexes may be excluded in which L is
substituted or unsubstituted quinolin-8-yl. Alternatively, said
metal complexes may be excluded in which L is quinolin-8-yl. In the
following, the present invention will be explained in more detail
referring to one specific embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0075] A zinc complex having composition M2L.sub.2 and supposed
structure E2, with an electron withdrawing ligand L with a
perfluorphenyl group bound to a nitrogen, has been prepared.
Further detailed studies on E2, however, revealed that its
sublimation is in fact accompanied by a chemical change, because
the sublimed complex differs in its structure and composition from
the starting material. More specifically, the sublimed material
partly formed monocrystals of a size and quality suitable for X-ray
diffraction (XRD); the structure and composition of this material,
assigned herein as E.sub.3, has been fully resolved by this
method.
[0076] The XRD revealed that the sublimed material has an
unexpected composition Zn.sub.4OL.sub.6 and a cluster structure E3
shown in FIG. 4.
##STR00005##
[0077] Due to complexity o molecule E3 having summary formula
C.sub.42F.sub.48N.sub.6O.sub.13S.sub.6Zn.sub.4, the structure shall
be described in the next paragraph in form of a guide:
[0078] The molecule consists of the central oxide dianion,
tetrahedrally coordinated with four Zn dications, bridged with six
monoanionic ligands L (which are per se structurally identical as
in formula E2) in the way that on each edge of the central Zn.sub.4
tetrahedron, one L is bound to both Zn cations through its N and O
atoms, respectively, forming thus with both Zn cations and the
central oxide dianion a six-membered --Zn--O--Zn--N--S--O--
ring.
[0079] In the present application, the prior art compound B2
##STR00006##
[0080] known for use in organic light emitting diodes of the prior
art, in particular in hole injection materials thereof or as
p-dopant, has been used as the reference material to show
superiority of the inventive materials.
[0081] Further Layers
[0082] In accordance with the invention, the electronic device may
comprise, besides the layers already mentioned above, further
layers. Exemplary embodiments of respective layers are described in
the following:
[0083] Substrate
[0084] The substrate may be any substrate that is commonly used in
manufacturing of, electronic devices, such as organic
light-emitting diodes. If light is to be emitted through the
substrate, the substrate shall be a transparent or semitransparent
material, for example a glass substrate or a transparent plastic
substrate. If light is to be emitted through the top surface, the
substrate may be both a transparent as well as a non-transparent
material, for example a glass substrate, a plastic substrate, a
metal substrate or a silicon substrate.
[0085] Anode Electrode
[0086] Either the first electrode or the second electrode may be an
anode electrode. The anode electrode may be formed by depositing or
sputtering a material that is used to form the anode electrode. The
material used to form the anode electrode may be a high
work-function material, so as to facilitate hole injection. The
anode material may also be selected from a low work function
material (i.e. aluminum). The anode electrode may be a transparent
or reflective electrode. Transparent conductive oxides, such as
indium tin oxide (ITO), indium zinc oxide (IZO), tin-dioxide
(SnO2), aluminum zinc oxide (AlZO) and zinc oxide (ZnO), may be
used to form the anode electrode. The anode electrode may also be
formed using metals, typically silver (Ag), gold (Au), or metal
alloys.
[0087] Hole Injection Layer
[0088] In accordance with the invention, the hole injection layer
may comprise or consist of a coordination complex (respectively an
inverse coordination complex) as described above in very detail.
The hole injection layer (HIL) may be formed on the anode electrode
by vacuum deposition, spin coating, printing, casting, slot-die
coating, Langmuir-Blodgett (LB) deposition, or the like. When the
HIL is formed using vacuum deposition, the deposition conditions
may vary according to the compound that is used to form the HIL,
and the desired structure and thermal properties of the HIL. In
general, however, conditions for vacuum deposition may include a
deposition temperature of 100.degree. C. to 500.degree. C., a
pressure of 10.sup.-8 to 10.sup.-3 Torr (1 Torr equals 133.322 Pa),
and a deposition rate of 0.1 to 10 nm/sec.
[0089] When the HIL is formed using spin coating or printing,
coating conditions may vary according to the compound that is used
to form the HIL, and the desired structure and thermal properties
of the HIL. For example, the coating conditions may include a
coating speed of about 2000 rpm to about 5000 rpm, and a thermal
treatment temperature of about 80.degree. C. to about 200.degree.
C. Thermal treatment removes a solvent after the coating is
performed.
[0090] The HIL may be formed--if the electronic device comprises
besides the hole injection layer and/or a hole generating layer and
the hole transport layer and/or the hole generating layer comprises
the (inverse) coordination complex--of any compound that is
commonly used to form a HIL. Examples of compounds that may be used
to form the HIL include a phthalocyanine compound, such as copper
phthalocyanine (CuPc), 4,4',4''-tris (3-methylphenylphenylamino)
triphenylamine (m-MTDATA), TDATA, 2T-NATA,
polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA),
poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate)
(PEDOT/PSS), polyaniline/camphor sulfonic acid (Pani/CSA), and
polyaniline)/poly(4-styrenesulfonate (PANI/PSS).
[0091] In such a case, the HIL may be a pure layer of p-dopant or
may be selected from a hole-transporting matrix compound doped with
a p-dopant. Typical examples of known redox doped hole transport
materials are: copper phthalocyanine (CuPc), which HOMO level is
approximately -5.2 eV, doped with
tetrafluoro-tetracyanoquinonedimethane (F.sub.4TCNQ), which LUMO
level is about -5.2 eV; zinc phthalocyanine (ZnPc) (HOMO=-5.2 eV)
doped with F.sub.4TCNQ; .alpha.-NPD
(N,N'-Bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine) doped with
F.sub.4TCNQ. .alpha.-NPD doped with
2,2'-(perfluoronaphthalen-2,6-diylidene) dimalononitrile (PD1).
.alpha.-NPD doped with
2,2',2''-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)-
acetonitrile) (PD2). Dopant concentrations can be selected from 1
to 20 wt. -%, more preferably from 3 wt. -% to 10 wt. -%.
[0092] The thickness of the HIL may be in the range from about 1 nm
to about 100 nm, and for example, from about 1 nm to about 25 nm.
When the thickness of the HIL is within this range, the HIL may
have excellent hole injecting characteristics, without a
substantial penalty in driving voltage.
[0093] Hole Transport Layer
[0094] In accordance with the invention, the hole transport layer
may comprise or consist of a coordination complex, respectively an
inverse coordination complex, as described above in detail.
[0095] The hole transport layer (HTL) may be formed on the HIL by
vacuum deposition, spin coating, slot-die coating, printing,
casting, Langmuir-Blodgett (LB) deposition, or the like. When the
HTL is formed by vacuum deposition or spin coating, the conditions
for deposition and coating may be similar to those for the
formation of the HIL. However, the conditions for the vacuum or
solution deposition may vary, according to the compound that is
used to form the HTL.
[0096] In case that the HTL does not comprise an (inverse)
coordination complex in accordance with the invention, but the
(inverse) coordination complex is comprised in the HIL and/or the
CGL, the HTL may be formed by any compound that is commonly used to
form a HTL. Compounds that can be suitably used are disclosed for
example in Yasuhiko Shirota and Hiroshi Kageyama, Chem. Rev. 2007,
107, 953-1010 and incorporated by reference. Examples of the
compound that may be used to form the HTL are: carbazole
derivatives, such as N-phenylcarbazole or polyvinylcarbazole;
benzidine derivatives, such as
N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine
(TPD), or N,N'-di(naphthalen-1-yl)-N,N'-diphenyl benzidine
(alpha-NPD); and triphenylamine-based compound, such as
4,4',4''-tris(N-carbazolyl)triphenylamine (TCTA). Among these
compounds, TCTA can transport holes and inhibit excitons from being
diffused into the EML.
[0097] The thickness of the HTL may be in the range of about 5 nm
to about 250 nm, preferably, about 10 nm to about 200 nm, further
about 20 nm to about 190 nm, further about 40 nm to about 180 nm,
further about 60 nm to about 170 nm, further about 80 nm to about
160 nm, further about 100 nm to about 160 nm, further about 120 nm
to about 140 nm. A preferred thickness of the HTL may be 170 nm to
200 nm.
[0098] When the thickness of the HTL is within this range, the HTL
may have excellent hole transporting characteristics, without a
substantial penalty in driving voltage.
[0099] Electron Blocking Layer
[0100] The function of the electron blocking layer (EBL) is to
prevent electrons from being transferred from the emission layer to
the hole transport layer and thereby confine electrons to the
emission layer. Thereby, efficiency, operating voltage and/or
lifetime are improved. Typically, the electron blocking layer
comprises a triarylamine compound. The triarylamine compound may
have a LUMO level closer to vacuum level than the LUMO level of the
hole transport layer. The electron blocking layer may have a HOMO
level that is further away from vacuum level compared to the HOMO
level of the hole transport layer. The thickness of the electron
blocking layer may be select between 2 and 20 nm.
[0101] the electron blocking layer may comprise a compound of
formula Z below (Z).
##STR00007##
[0102] In Formula Z, CY1 and CY2 are the same as or different from
each other, and each independently represent a benzene cycle or a
naphthalene cycle, Ar1 to Ar3 are the same as or different from
each other, and each independently selected from the group
consisting of hydrogen; a substituted or unsubstituted aryl group
having 6 to 30 carbon atoms; and a substituted or unsubstituted
heteroaryl group having 5 to 30 carbon atoms, Ar4 is selected from
the group consisting of a substituted or unsubstituted phenyl
group, a substituted or unsubstituted biphenyl group, a substituted
or unsubstituted terphenyl group, a substituted or substituted
triphenylene group, and a substituted or unsubstituted heteroaryl
group having 5 to 30 carbon atoms, L is a substituted or
unsubstituted arylene group having 6 to 30 carbon atoms.
[0103] If the electron blocking layer has a high triplet level, it
may also be described as triplet control layer.
[0104] the function of the triplet control layer is to reduce
quenching of triplets if a phosphorescent green or blue emission
layer is used. Thereby, higher efficiency of light emission from a
phosphorescent emission layer can be achieved. The triplet control
layer is selected from triarylamine compounds with a triplet level
above the triplet level of the phosphorescent emitter in the
adjacent emission layer. Suitable compounds for the triplet control
layer, in particular the triarylamine compounds, are described in
EP 2 722 908 A1.
[0105] Emission Layer (EML)
[0106] The EML may be formed on the HTL by vacuum deposition, spin
coating, slot-die coating, printing, casting, deposition, or the
like. When the EML is formed using vacuum deposition or spin
coating, the conditions for deposition and coating may be similar
to those for the formation of the HIL. However, the conditions for
deposition and coating may vary, according to the compound that is
used to form the EML.
[0107] The emission layer (EML) may be formed of a combination of a
host and an emitter dopant. Example of the host are Alq3,
4,4'-N,N'-dicarbazole-biphenyl (CBP), poly(n-vinylcarbazole) (PVK),
9,10-di(naphthalene-2-yl)anthracene (ADN),
4,4',4''-tris(carbazol-9-yl)-triphenylamine(TCTA),
1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBI),
3-tert-butyl-9,10-di-2-naphthylanthracenee (TBADN), distyrylarylene
(DSA), bis(2-(2-hydroxyphenyl)benzo-thiazolate)zinc
(Zn(BTZ).sub.2), G.sub.3 below, AND, Compound 1 below, and Compound
2 below.
##STR00008##
[0108] The emitter dopant may be a phosphorescent or fluorescent
emitter. Phosphorescent emitters and emitters which emit light via
a thermally activated delayed fluorescence (TADF) mechanism may be
preferred due to their higher efficiency. The emitter may be a
small molecule or a polymer.
[0109] Examples of red emitter dopants are PtOEP, Ir(piq).sub.3,
and Btp.sub.2Ir(acac), but are not limited thereto. These compounds
are phosphorescent the emitters, however, fluorescent red emitter
dopants could also be used.
##STR00009##
[0110] Examples of phosphorescent green emitter dopants are
Ir(ppy).sub.3 (ppy=phenylpyridine), Ir(ppy).sub.2(acac),
Ir(mpyp).sub.3 are shown below. Compound 3 is an example of a
fluorescent green emitter and the s the is shown below.
##STR00010##
[0111] Examples of phosphorescent blue emitter dopants are F2Irpic,
(F2ppy)2Ir(tmd) and Ir(dfppz)3, ter-fluorene, the structures are
shown below. 4,4'-bis(4-diphenyl amiostyryl)biphenyl (DPAVBi),
2,5,8,11-tetra-tert-butyl perylene (TBPe), and Compound 4 below are
examples of fluorescent blue emitter dopants.
##STR00011##
[0112] The amount of the emitter dopant may be in the range from
about 0.01 to about 50 parts by weight, based on 100 parts by
weight of the host. Alternatively, the emission layer may consist
of a light-emitting polymer. The EML may have a thickness of about
10 nm to about 100 nm, for example, from about 20 nm to about 60
nm. When the thickness of the EML is within this range, the EML may
have excellent light emission, without a substantial penalty in
driving voltage.
[0113] Hole Blocking Layer (HBL)
[0114] A hole blocking layer (HBL) may be formed on the EML, by
using vacuum deposition, spin coating, slot-die coating, printing,
casting, LB deposition, or the like, in order to prevent the
diffusion of holes into the ETL. When the EML comprises a
phosphorescent dopant, the HBL may have also a triplet exciton
blocking function.
[0115] When the HBL is formed using vacuum deposition or spin
coating, the conditions for deposition and coating may be similar
to those for the formation of the HIL. However, the conditions for
deposition and coating may vary, according to the compound that is
used to form the HBL. Any compound that is commonly used to form a
HBL may be used. Examples of compounds for forming the HBL include
oxadiazole derivatives, triazole derivatives, and phenanthroline
derivatives.
[0116] The HBL may have a thickness in the range from about 5 nm to
about 100 nm, for example, from about 10 nm to about 30 nm. When
the thickness of the HBL is within this range, the HBL may have
excellent hole-blocking properties, without a substantial penalty
in driving voltage.
[0117] Electron Transport Layer (ETL)
[0118] The OLED according to the present invention may contain an
electron transport layer (ETL).
[0119] According to various embodiments, the OLED may comprise an
electron transport layer or an electron transport layer stack
comprising at least a first electron transport layer and at least a
second electron transport layer.
[0120] By suitably adjusting energy levels of particular layers of
the ETL, the injection and transport of the electrons may be
controlled, and the holes may be efficiently blocked. Thus, the
OLED may have long lifetime.
[0121] The electron transport layer of the electronic device may
comprise an organic electron transport matrix (ETM) material.
Further, the electron transport layer may comprise one or more
n-dopants. Suitable compounds for the ETM are not particularly
limited. In one embodiment, the electron transport matrix compounds
consist of covalently bound atoms. Preferably, the electron
transport matrix compound comprises a conjugated system of at least
6, more preferably of at least 10 delocalized electrons. In one
embodiment, the conjugated system of delocalized electrons may be
comprised in aromatic or heteroaromatic structural moieties, as
disclosed e.g. in documents EP 1 970 371 A1 or WO 2013/079217
A1.
[0122] Electron Injection Layer (EIL)
[0123] The optional EIL, which may facilitates injection of
electrons from the cathode, may be formed on the ETL, preferably
directly on the electron transport layer. Examples of materials for
forming the EIL include lithium 8-hydroxyquinolinolate (LiQ), LiF,
NaCl, CsF, Li.sub.2O, BaO, Ca, Ba, Yb, Mg which are known in the
art. Deposition and coating conditions for forming the EIL are
similar to those for formation of the HIL, although the deposition
and coating conditions may vary, according to the material that is
used to form the EIL.
[0124] The thickness of the EIL may be in the range from about 0.1
nm to about 10 nm, for example, in the range from about 0.5 nm to
about 9 nm. When the thickness of the EIL is within this range, the
EIL may have satisfactory electron-injecting properties, without a
substantial penalty in driving voltage.
[0125] Cathode Electrode
[0126] The cathode electrode is formed on the EIL if present. The
cathode electrode may be formed of a metal, an alloy, an
electrically conductive compound, or a mixture thereof. The cathode
electrode may have a low work function. For example, the cathode
electrode may be formed of lithium (Li), magnesium (Mg), aluminum
(Al), aluminum (Al)-lithium (Li), calcium (Ca), barium (Ba),
ytterbium (Yb), magnesium (Mg)-indium (In), magnesium (Mg)-silver
(Ag), or the like. Alternatively, the cathode electrode may be
formed of a transparent conductive oxides, such as ITO or IZO.
[0127] The thickness of the cathode electrode may be in the range
from about 5 nm to about 1000 nm, for example, in the range from
about 10 nm to about 100 nm. When the thickness of the cathode
electrode is in the range from about 5 nm to about 50 nm, the
cathode electrode may be transparent or semitransparent even if
formed from a metal or metal alloy.
[0128] It is to be understood that the cathode electrode is not
part of an electron injection layer or the electron transport
layer.
[0129] Charge Generation Layer/Hole Generating Layer
[0130] The charge generation layer (CGL) may be composed of a
double layer.
[0131] Typically, the charge generation layer is a pn junction
joining a n-type charge generation layer (electron generating
layer) and a hole generating layer. The n-side of the pn junction
generates electrons and injects them into the layer which is
adjacent in the direction to the anode. Analogously, the p-side of
the p-n junction generates holes and injects them into the layer
which is adjacent in the direction to the cathode.
[0132] Charge generating layers are used in tandem devices, for
example, in tandem OLEDs comprising, between two electrodes, two or
more emission layers. In aa tandem OLED comprising two emission
layers, the n-type charge generation layer provides electrons for
the first light emission layer arranged near the anode, while the
hole generating layer provides holes to the second light emission
layer arranged between the first emission layer and the
cathode.
[0133] In accordance with the invention, it may be provided that
the electronic device comprises a hole injection layer as well as a
hole generating layer. If the hole injection layer comprises the
(inverse) coordination complex, it is not obligatory that also the
hole generating layer comprises the (inverse) coordination complex.
In such a case, the hole generating layer can be composed of an
organic matrix material doped with p-type dopant. Suitable matrix
materials for the hole generating layer may be materials
conventionally used as hole injection and/or hole transport matrix
materials. Also, p-type dopant used for the hole generating layer
can employ conventional materials. For example, the p-type dopant
can be one selected from a group consisting of
tetrafluore-7,7,8,8-tetracyanoquinodimethane (F.sub.4-TCNQ),
derivatives of tetracyanoquinodimethane, radialene derivatives,
iodine, FeCl.sub.3, FeF.sub.3, and SbCl.sub.5. Also, the host can
be one selected from a group consisting of
N,N'-di(naphthalen-1-yl)-N,N-diphenyl-benzidine (NPB),
N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1-biphenyl-4, 4'-diamine
(TPD) and N,N',N'-tetranaphthyl-benzidine (TNB).
[0134] In a preferred embodiment, the hole generating layer
consists of the coordination complex or the inverse coordination
complex as defined above in detail.
[0135] The n-type charge generation layer can be layer of a neat
n-dopant, for example of an electropositive metal, or can consist
of an organic matrix material doped with the n-dopant. In one
embodiment, the n-type dopant can be alkali metal, alkali metal
compound, alkaline earth metal, or alkaline earth metal compound.
In another embodiment, the metal can be one selected from a group
consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu,
Tb, Dy, and Yb. More specifically, the n-type dopant can be one
selected from a group consisting of Cs, K, Rb, Mg, Na, Ca, Sr, Eu
and Yb. Suitable matrix materials for the electron generating layer
may be the materials conventionally used as matrix materials for
electron injection or electron transport layers. The matrix
material can be for example one selected from a group consisting of
triazine compounds, hydroxyquinoline derivatives like
tris(8-hydroxyquinoline)aluminum, benzazole derivatives, and silole
derivatives.
[0136] In one embodiment, the n-type charge generation layer may
include compounds of the following Chemical Formula X.
##STR00012##
[0137] wherein each of A1 to A6 may be hydrogen, a halogen atom,
nitrile (--CN), nitro (--NO2), sulfonyl (--SO2R), sulfoxide
(--SOR), sulfonamide (--SO2NR), sulfonate (--SO3R), trifiuoromethyl
(--CF3), ester (--COOR), amide (--CONHR or --CONRR'), substituted
or unsubstituted straight-chain or branched-chain C.sub.1-C.sub.12
alkoxy, substituted or unsubstituted straight-chain or
branched-chain C.sub.1-C.sub.12 alkyl, substituted or unsubstituted
straight-chain or branched chain C.sub.2-C.sub.12 alkenyl, a
substituted or unsubstituted aromatic or non-aromatic heteroring,
substituted or unsubstituted aryl, substituted or unsubstituted
mono- or di-arylamine, substituted or unsubstituted aralkylamine,
or the like. Herein, each of the above R and R' may be substituted
or unsubstituted C.sub.1-C.sub.60 alkyl, substituted or
unsubstituted a substituted or substituted 5- to 7-membered
heteroring, or the like.
[0138] An example of such the charge generation layer may be a
layer comprising CNHAT
##STR00013##
[0139] The hole generating layer is arranged on top of the n-type
charge generation layer.
[0140] Organic Light-emitting Diode (OLED)
[0141] According to one aspect of the present invention, there is
provided an organic light-emitting diode (OLED) comprising: a
substrate; an anode electrode formed on the substrate; a hole
injection layer, a hole transport layer, an emission layer, and a
cathode electrode.
[0142] According to another aspect of the present invention, there
is provided an OLED comprising a substrate; anode electrode formed
on the substrate; a hole injection layer, a hole transport layer,
an electron blocking layer, an emission layer, a hole blocking
layer and a cathode electrode.
[0143] According to other aspect of the present invention, there is
provided an OLED comprising: a substrate; an anode electrode formed
on the substrate; a hole injection layer, a hole transport layer,
an electron blocking layer, an emission layer, a hole blocking
layer, an electron transport layer, and a cathode electrode.
[0144] According to another aspect of the present invention, there
is provided an OLED comprising: a substrate; anode electrode formed
on the substrate; a hole injection layer, a hole transport layer,
an electron blocking layer, emission layer, a hole blocking layer,
an electron transport layer, an electron injection layer, and a
cathode electrode.
[0145] According to various embodiments of the present invention,
there may be provided OLEDs layers arranged between the above
mentioned layers, on the substrate or on the top electrode.
[0146] According to one aspect, the OLED can comprise a layer
structure of a substrate that is adjacent arranged to an anode
electrode, the anode electrode is adjacent arranged to a first hole
injection layer, the first hole injection layer is adjacent
arranged to a first hole transport layer, the first hole transport
layer is adjacent arranged to a first electron blocking layer, the
first electron blocking layer is adjacent arranged to a first
emission layer, the first emission layer is adjacent arranged to a
first electron transport layer, the first electron transport layer
is adjacent arranged to an n-type charge generation layer, the
n-type charge generation layer is adjacent arranged to a hole
generating layer, the hole generating layer is adjacent arranged to
a second hole transport layer, the second hole transport layer is
adjacent arranged to a second electron blocking layer, the second
electron blocking layer is adjacent arranged to a second emission
layer, between the second emission layer and the cathode electrode
an optional electron transport layer and/or an optional injection
layer are arranged.
[0147] For example, the OLED according to FIG. 2 may be formed by a
process, wherein [0148] on a substrate (110), an anode (120), a
hole injection layer (130), a hole transport layer (140), an
electron blocking layer (145), an emission layer (150), a hole
blocking layer (155), an electron transport layer (160), an
electron injection layer (180) and the cathode electrode (190) are
subsequently formed in that order.
[0149] Details and Definitions of the Invention
[0150] The present invention is related to an electronic device.
The device comprises a first electrode and a second electrode.
Between the first electrode and the second electrode, at least one
hole injection layer and/or at least one hole transport layer
and/or at least one hole generating layer is arranged. That is, the
electronic device may only comprise a hole injection layer between
the first electrode and the second electrode. Likewise, the
inventive electronic device may only comprise the hole transport
layer between the first electrode and the second electrode.
Likewise, the inventive electronic device may only comprise the
hole generating layer between the first electrode and the second
electrode. likewise, the electronic device may comprise only two or
all three of the above hole injection, hole transport or hole
generating layers between the first electrode and the second
electrode. In case that electronic device only comprises the hole
injection layer (and not the hole generating layer) it is provided
that the hole injection layer consists of the (inverse)
coordination complex. Likewise, in the case that the electronic and
device comprises only the hole generating layer (and not the hole
injection layer) it is provided that the hole generating layer
consists of the (inverse) coordination complex. In case that the
electronic device comprises both the hole injection layer and the
hole generating layer, it may be provided that only the hole
injection layer consists of the (inverse) coordination complex,
that only the hole generating layer consists of the (inverse)
coordination complex or that both the hole injection layer and the
hole generating layer consist of the (inverse) coordination
complex.
[0151] In the above definition of the invention, reference is made
to the electronegativity values according to Allen. According to
Allen, the electronegativity of an atom is related to the average
energy of the valence electrons in a free atom thereof. The
electronegativity values according to Allen are as follows. For
lanthanide elements LaYb, it is assumed that Allen
electronegativity is less than 1.15, for Th and U, it is assumed
that Allen electronegativity is less than 1.5.
TABLE-US-00001 Electronegativity using the Allen scale Group Period
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 H He 2.300 4.160 2
Li Be B C N O F Ne 0.912 1.576 2.051 2.544 3.066 3.610 4.193 4.787
3 Na Mg Al Si P S Cl Ar 0.869 1.293 1.613 1.916 2.253 2.589 2.869
3.242 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 0.734
1.034 1.19 1.38 1.53 1.65 1.75 1.80 1.84 1.88 1.85 1.59 1.756 1.994
2.211 2.424 2.685 2.966 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn
Sb Te I Xe 0.706 0.963 1.12 1.32 1.41 1.47 1.51 1.54 1.56 1.58 1.87
1.52 1.656 1.824 1.984 2.158 2.359 2.582 6 Cs Ba Lu Hf Ta W Re Os
Ir Pt Au Hg Tl Pb Bi Po At Rn 0.659 0.881 1.09 1.16 1.34 1.47 1.60
1.65 1.68 1.72 1.92 1.76 1.789 1.854 2.01 2.19 2.39 2.60 7 Fr Ra
0.67 0.89
[0152] The term "hydrocarbyl group" as used herein shall be
understood to encompass any organic group comprising carbon atoms,
in particular organic groups, such as alkyl, aryl, heteroaryl,
heteroalkyl, in particular such groups which are substituents usual
in organic electronics.
[0153] The term "alkyl" as used herein shall encompass linear as
well as branched and cyclic alkyl. For example, C.sub.3-alkyl may
be selected from n-propyl and iso-propyl. Likewise, C.sub.4-alkyl
encompasses n-butyl, sec-butyl and t-butyl. Likewise, C.sub.6-alkyl
encompasses n-hexyl and cyclo-hexyl.
[0154] The subscribed number n in C.sub.n relates to the total
number of carbon atoms in the respective alkyl, arylene,
heteroarylene or aryl group.
[0155] The term "aryl" as used herein shall encompass phenyl
(C.sub.6-aryl), fused aromatics, such as naphthalene, anthracene,
phenanthrene, tetracene etc. Further encompassed are biphenyl and
oligo- or polyphenyls, such as terphenyl etc. Further encompassed
shall be any further aromatic hydrocarbon substituents, such as
fluorenyl etc. Arylene, respectively heteroarylene refers to groups
to which two further moieties are attached.
[0156] The term "heteroaryl" as used herein refers to aryl groups
in which at least one carbon atom is substituted by a heteroatom,
preferably selected from N, O, S, B or Si.
[0157] The term "halogenated" refers to an organic compound in
which one hydrogen atom thereof is replaced by a halogen atom. The
term "perhalogenated" refers to an organic compound in which all of
the hydrogen atoms thereof are replaced by halogen atoms. The
meaning of the terms "fluorinated" and "perfluorinated" should be
understood analogously.
[0158] The subscripted number n in C.sub.n-heteroaryl merely refers
to the number of carbon atoms excluding the number of heteroatoms.
In this context, it is clear that a C.sub.3 heteroarylene group is
an aromatic compound comprising three carbon atoms, such as
pyrazol, imidazole, oxazole, thiazole and the like.
[0159] In terms of the invention, the expression "between" with
respect to one layer being between two other layers does not
exclude the presence of further layers which may be arranged
between the one layer and one of the two other layers. In terms of
the invention, the expression "in direct contact" with respect to
two layers being in direct contact with each other means that no
further layer is arranged between those two layers. One layer
deposited on the top of another layer is deemed to be in direct
contact with this layer.
[0160] With respect to the inventive organic semiconductive layer
as well as with respect to the inventive compound, the compounds
mentioned in the experimental part are most preferred.
[0161] The inventive electronic device may be an organic
electroluminescent device (OLED) an organic photovoltaic device
(OPV) or an organic field-effect transistor (OFET).
[0162] According to another aspect, the organic electroluminescent
device according to the present invention may comprise more than
one emission layer, preferably two or three emission layers. An
OLED comprising more than one emission layer is also described as a
tandem OLED or stacked OLED.
[0163] The organic electroluminescent device (OLED) may be a
bottom- or top-emission device.
[0164] Another aspect is directed to a device comprising at least
one organic electroluminescent device (OLED). A device comprising
organic light-emitting diodes is for example a display or a
lighting panel.
[0165] In the present invention, the following defined terms, these
definitions shall be applied, unless a different definition is
given in the claims or elsewhere in this specification.
[0166] In the context of the present specification the term
"different" or "differs" in connection with the matrix material
means that the matrix material differs in their structural
formula.
[0167] The energy levels of the highest occupied molecular orbital,
also named HOMO, and of the lowest unoccupied molecular orbital,
also named LUMO, are measured in electron volt (eV).
[0168] The terms "OLED" and "organic light-emitting diode" are
simultaneously used and have the same meaning. The term "organic
electroluminescent device" as used herein may comprise both organic
light emitting diodes as well as organic light emitting transistors
(OLETs).
[0169] As used herein, "weight percent", "wt. -%", "percent by
weight", "% by weight", and variations thereof refer to a
composition, component, substance or agent as the weight of that
component, substance or agent of the respective electron transport
layer divided by the total weight of the respective electron
transport layer thereof and multiplied by 100. It is under-stood
that the total weight percent amount of all components, substances
and agents of the respective electron transport layer and electron
injection layer are selected such that it does not exceed 100 wt.
-%.
[0170] As used herein, "volume percent", "vol. -%", "percent by
volume", "% by volume", and variations thereof refer to a
composition, component, substance or agent as the volume of that
component, substance or agent of the respective electron transport
layer divided by the total volume of the respective electron
transport layer thereof and multiplied by 100. It is understood
that the total volume percent amount of all components, substances
and agents of the cathode layer are selected such that it does not
exceed 100 vol. -%.
[0171] All numeric values are herein assumed to be modified by the
term "about", whether or not explicitly indicated. As used herein,
the term "about" refers to variation in the numerical quantity that
can occur. Whether or not modified by the term "about" the claims
include equivalents to the quantities.
[0172] It should be noted that, as used in this specification and
the appended claims, the singular forms "a", "an", and "the"
include plural referents unless the content clearly dictates
otherwise.
[0173] The term "free of", "does not contain", "does not comprise"
does not exclude impurities. Impurities have no technical effect
with respect to the object achieved by the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0174] These and/or other aspects and advantages of the present
invention will become apparent and more readily appreciated from
the following description of the exemplary embodiments, taken in
conjunction with the accompanying drawings, of which:
[0175] FIG. 1 is a schematic sectional view of an organic
light-emitting diode (OLED), according to an exemplary embodiment
of the present invention;
[0176] FIG. 2 is a schematic sectional view of an OLED, according
to an exemplary embodiment of the present invention.
[0177] FIG. 3 is a schematic sectional view of a tandem OLED
comprising a charge generation layer, according to an exemplary
embodiment of the present invention.
[0178] FIG. 4 shows the crystal structure of the inventive inverse
coordination complex E3, having the summary formula
C.sub.42F.sub.48N.sub.6O.sub.13S.sub.6Zn.sub.4.
EMBODIMENTS OF THE INVENTIVE DEVICE
[0179] Reference will now be made in detail to the exemplary
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to the like elements throughout. The exemplary
embodiments are described below, in order to explain the aspects of
the present invention, by referring to the figures.
[0180] Herein, when a first element is referred to as being formed
or disposed "on" a second element, the first element can be
disposed directly on the second element, or one or more other
elements may be disposed there between. When a first element is
referred to as being formed or disposed "directly on" a second
element, no other elements are disposed there between.
[0181] FIG. 1 is a schematic sectional view of an organic
light-emitting diode (OLED) 100, according to an exemplary
embodiment of the present invention. The OLED 100 includes a
substrate 110, an anode 120, a hole injection layer (HIL) 130, a
hole transport layer (HTL) 140, an emission layer (EML) 150, an
electron transport layer (ETL) 160. The electron transport layer
(ETL) 160 is formed directly on the EML 150. Onto the electron
transport layer (ETL) 160, an electron injection layer (EIL) 180 is
disposed. The cathode 190 is disposed directly onto the electron
injection layer (EIL) 180.
[0182] Instead of a single electron transport layer 160, optionally
an electron transport layer stack (ETL) can be used.
[0183] FIG. 2 is a schematic sectional view of an OLED 100,
according to another exemplary embodiment of the present invention.
FIG. 2 differs from FIG. 1 in that the OLED 100 of FIG. 2 comprises
an electron blocking layer (EBL) 145 and a hole blocking layer
(HBL) 155.
[0184] Referring to FIG. 2, the OLED 100 includes a substrate 110,
an anode 120, a hole injection layer (HIL) 130, a hole transport
layer (HTL) 140, an electron blocking layer (EBL) 145, an emission
layer (EML) 150, a hole blocking layer (HBL) 155, an electron
transport layer (ETL) 160, an electron injection layer (EIL) 180
and a cathode electrode 190.
[0185] FIG. 3 is a schematic sectional view of a tandem OLED 200,
according to another exemplary embodiment of the present invention.
FIG. 3 differs from FIG. 2 in that the OLED 100 of FIG. 3 further
comprises a charge generation layer and a second emission
layer.
[0186] Referring to FIG. 3, the OLED 200 includes a substrate 110,
an anode 120, a first hole injection layer (HIL) 130, a first hole
transport layer (HTL) 140, a first electron blocking layer (EBL)
145, a first emission layer (EML) 150, a first hole blocking layer
(HBL) 155, a first electron transport layer (ETL) 160, an n-type
charge generation layer (n-type CGL) 185, a hole generating layer
(p-type charge generation layer; p-type GCL) 135, a second hole
transport layer (HTL) 141, a second electron blocking layer (EBL)
146, a second emission layer (EML) 151, a second hole blocking
layer (EBL) 156, a second electron transport layer (ETL) 161, a
second electron injection layer (EIL) 181 and a cathode 190.
[0187] While not shown in FIG. 1, FIG. 2 and FIG. 3, a sealing
layer may further be formed on the cathode electrodes 190, in order
to seal the OLEDs 100 and 200. In addition, various other
modifications may be applied thereto.
[0188] Hereinafter, one or more exemplary embodiments of the
present invention will be described in detail with, reference to
the following examples. However, these examples are not intended to
limit the purpose and scope of the one or more exemplary
embodiments of the present invention.
[0189] Experimental Part
[0190] Preparation of Inventive Metal Complexes
[0191] Exemplary Compound E2
[0192] The compound has been prepared according to Scheme 1
##STR00014##
[0193] 1. Step 1: Synthesis of
1,1,1-trifluoro-N-(Perfluorophenyl)Methanesulfonamide
[0194] A 250 mL Schlenk flask was heated in vacuum and after
cooling was purged with nitrogen. Perfluoroaniline was dissolved in
100 mL toluene and the solution was cooled to -80.degree. C. A 1.7
M t-Butyllithium solution was added dropwise via syringe over 10
min. The reaction solution changed from clear to cloudy and was
stirred for 1 h at -80.degree. C. After that, the solution was
allowed to warm to -60.degree. C. and 1.1 eq of
trifluoromethanesulfonic anhydride was added dropwise to the
solution. Then the cooling bath was removed and the reaction
mixture was allowed to warm slowly to ambient temperature and
stirred overnight, whereby the color changed to light orange.
Additionally, a white solid formed. The precipitated by-product
lithium trifluoromethanesulfonate was filtered off by suction
filtration over a sintered glass filter and washed with 2.times.30
mL toluene and 30 mL n-hexane. The orange filtrate was evaporated
and dried in high vacuum forming crystals. The crude product was
then purified by bulb-to-bulb distillation (135.degree. C. @
1.2.times.10.sup.-1 mbar) resulting in a crystalline colorless
solid (main fraction).
[0195] .sup.1H NMR [d.sup.6-DMSO, ppm] .delta.: 13.09 (s, 1 H,
N-H).
[0196] .sup.13C{.sup.1H} NMR [d.sup.6-DMSO, ppm] .delta.: 116.75
(m, Ci-C6F.sub.5), 120.74 (q,.sup.1J.sub.CF=325 Hz, CF.sub.3),
136.39, 138.35 (2m, .sup.2J.sub.CF=247 Hz, m-C6F.sub.5), 137.08,
139.06 (2m, .sup.2J.sub.CF=247 Hz, p-C6F.sub.5), 142.98, 144.93
(2m, .sup.2J.sub.CF=247, Hz o-C6F.sub.5).
[0197] .sup.1H NMR [d.sup.6-DMSO, ppm] .delta.: -77.45 (m,
CF.sub.3), -148.12 (m, C6F.sub.5), -160.79 (m,p-C6F.sub.5), -164.51
(m, C6F.sub.5).
[0198] ESI-MS: m/z-neg=314 (M-H).
[0199] EI-MS: m/z=315 (M), 182 (M-SO.sub.2CF.sub.3), 69
(CF.sub.3).
[0200] Step 2: Synthesis of
Bis((1,1,1-trifluoro-N-(Perfluorophenyl)Methyl)-sulfonamido)Zinc
[0201] A 100 mL Schlenk flask was heated in vacuum and after
cooling was purged with nitrogen.
1,1,1-Trifluoro-N-(perfluorophenyl)methanesulfonamide was dissolved
in 10 mL toluene and 0.5 eq of diethylzinc in hexane was added
dropwise to the solution via syringe at ambient temperature. During
the addition a fog was forming and the reaction solution became
jelly and cloudy. The solution was stirred for further 30 min at
this temperature. After that, 30 mL n-hexane were added and a white
precipitate formed, which was filtered over a sintered glass filter
(pore 4) under inert atmosphere. The filter cake was twice washed
with 15 mL n-hexane and dried in high vacuum at 100.degree. C. for
2 h
[0202] Yield: 660 mg (0.95 mmol, 60% based on
1,1,1-trifluoro-N-perfluorophenyl)methanesulfonamide) as a white
solid.
[0203] .sup.13C{.sup.1H} NMR [d.sup.6-DMSO, ppm] .delta.: 121.68
(q, .sup.1J.sub.CF=328 Hz, CF.sub.3), 123.56 (m, Ci-C6F.sub.5),
133.98, 135.91 (2m, .sup.2J.sub.CF=243 Hz, p-C6F.sub.5), 136.15,
138.13 (2m, .sup.2J.sub.CF=249 Hz, m-C6F.sub.5), 142.33, 144.24
(2m, .sup.2J.sub.CF=240, Hz o-C6F.sub.5).
[0204] .sup.19F NMR [d.sup.6-DMSO, ppm] .delta.: -77.52 (m,
CF.sub.3), -150.43 (m, C6F.sub.5), -166.77 (m, C6F.sub.5), -168.23
(m, p-C6F.sub.5).
[0205] ESI-MS: m/z-neg=314 (M-Zn-L).
[0206] EI-MS: m/z=692 (M), 559 (M-SO.sub.2CF.sub.3) 315
(C6F.sub.5NHSO.sub.2CF.sub.3), 182 (C6F.sub.5NH), 69
(CF.sub.3).
[0207] Exemplary Compound E3
[0208] 9.1 g E2 has been sublimed at the temperature 240.degree. C.
and pressure 10.sup.-3 Pa.
[0209] yield 5.9 g (65%).
[0210] The sublimed material formed colorless crystals. One crystal
of an appropriate shape and size (0.094.times.0.052.times.0.043
mm3) has been closed under Ar atmosphere in a glass capillary and
analyzed on Kappa Apex II diffractometer (Bruker-AXS, Karlsruhe,
Germany) with monochromatic X-ray radiation from a source provided
with molybdenum cathode (.lamda.=71.073 pm). Overall 37362
reflexions were collected within the theta range 1.881 to
28.306.degree..
[0211] The structure was resolved by direct method (SHELXS-97,
Sheldrick, 2008) and refined with a full-matrix least-squares
method (SHELXL-2014/7, Olex2 (Dolomanov, 2017).
[0212] Exemplary Compound E4
[0213] Step 1: Synthesis of
N-(3,5-bis(trifluoromethyl)phenyl)-1,1,1-trifluoromethanesulfoamide
##STR00015##
[0214] A 100 mL Schlenk flask was heated in vacuum and after
cooling was purged with nitrogen. The 3,5
bis(trifluoromethyl)aniline was dissolved in 40 mL toluene and the
solution was cooled to -80.degree. C. the t-Butyllithium solution
was added dropwise via syringe over 15 min. The resulting yellow
solution was stirred for 1.5h at -80.degree. C. The
trifluoromethanesulfonic anhydride added at -80.degree. C. The
cooling bath was removed and the reaction mixture was allowed to
warm slowly to ambient temperature and stirred overnight. The
reaction was then cooled in an ice-bath to <10.degree. C. and 70
ml 10% aqueous H2SO.sub.4-Solution was added slowly. The aqueous
phase was extracted three times with 75 mL diethyl ether and the
combined organic phases were washed with 100 mL water, dried over
sodium sulphate and the solvent removed under reduced pressure. The
resulting brownish oil distilled from bulb to bulb at 120.degree.
C. and 2e-02 mbar.
[0215] Yield: 5,23 g (83% based on anhydride); slightly yellow oil,
crystalizes slowly
[0216] Step 2: Synthesis of
bis(N-(3,5-bis(trifluoromethyl)phenyl)-1,1,1-trifluoromethyl)sulfonamido)-
zinc
##STR00016##
[0217]
N-(3,5-bis(trifluoromethyl)phenyl)-1,1,1-trifluoromethanesulfonamid-
e was dissolved in toluene in a dried Schlenk flask. A 1 M solution
of diethylzinc in toluene was added dropwise and the resulting
thick suspension was stirred overnight. The solid was filtered off
under inert conditions and washed with 20 ml hexane an dried under
high vacuum overnight.
[0218] Yield: 1.12 g (69%); white solid
[0219] By vacuum sublimation, E4 converted in compound and E5
having composition
C.sub.54H.sub.18F.sub.54N.sub.6O.sub.13S.sub.6Zn.sub.4 and forming
crystalline phase described above.
[0220] Further examples of inventive compounds were prepared
analogously:
[0221] E6, yield 99% based on
1,1,1-trifluoro-N-(perfluoropyridin-4-yl)meththanesulfon-amide,
according to Scheme 4
##STR00017##
[0222] E8, yield 81% based on
1,1,1-trifluoro-N-(2,5,6-trifluoro-pyrimidin-4-yl)methanesulfonamide)acco-
rding to Scheme 5
##STR00018##
[0223] E10, yield 92% based on
1,1,2,2,2-pentafluoro-N-perfluoro-pyridin-4-yl)ethane-1-sulfonamide,
according to Scheme 6
##STR00019##
[0224] E12, yield 80%, according to Scheme 7
##STR00020##
[0225] E14, yield 90%, according to Scheme 8
##STR00021##
[0226] E16, yield 85%, according to Scheme 9
##STR00022##
[0227] E18, yield 76%, according to Scheme 10
##STR00023##
[0228] E20, yield 82%, according to Scheme 11
##STR00024##
[0229] E22, yield 68%, according to Scheme 12
##STR00025##
[0230] E24, yield 67%, according to Scheme 13
##STR00026##
[0231] Device the Experiments
[0232] Generic Procedures
[0233] A 15.OMEGA./cm.sup.2 glass substrate with 90 nm ITO
(available from Corning Co.) was cut to a size of 150 mm.times.150
mm.times.0.7 mm, ultrasonically cleaned with isopropyl alcohol for
5 minutes and then with pure water for 5 minutes, and cleaned again
with UV ozone for 30 minutes, to prepare a first electrode.
[0234] The organic layers are deposited sequentially on the ITO
layer at 10.sup.-5 Pa, see Table 1 and 2 for compositions and layer
thicknesses. In the Tables 1 to 3, c refers to the concentration,
and d refers to the layer thickness.
[0235] Then, the cathode electrode layer is formed by evaporating
aluminum at ultra-high vacuum of 10.sup.-7 mbar and deposing the
aluminum layer directly on the organic semiconductor layer. A
thermal single co-evaporation of one or several metals is performed
with a rate of 0, 1 to 10 nm/s (0.01 to 1 .ANG./s) in order to
generate a homogeneous cathode electrode with a thickness of 5 to
1000 nm. The thickness of the cathode electrode layer is 100
nm.
[0236] The device is protected from ambient conditions by
encapsulation of the device with a glass slide. Thereby, a cavity
is formed, which comprises a getter material for further
protection.
[0237] Current voltage measurements are performed at the
temperature 20.degree. C. using a Keithley 2400 source meter, and
recorded in V.
[0238] Experimental Results
[0239] Materials Used in Device Experiments
[0240] The formulae of the supporting materials mentioned in both
tables below are as follows:
[0241] F1 is
##STR00027##
[0242]
biphenyl-4-yl(9,9-diphenyl-9H-fluoren-2-yl)-[4-(9-phenyl-9H-carbazo-
l-3-yl)phenyl]-amine, CAS 1242056-42-3;
[0243] F2 is
##STR00028##
[0244] (3-(dibenzo[c,h]acridin-7-yl)phenyl)diphenylphosphine oxide,
CAS 1440545-22-1;
[0245] F3 is
##STR00029##
[0246]
2,4-diphenyl-6-(3'-(triphenylen-2-yl)-[1,1'-biphenyl]-3-yl)-1,3,5-t-
riazine, CAS 1638271-85-8;
[0247] F4 is
##STR00030##
[0248] 1,3-bis(9-phenyl-1,10-phenanthrolin-2-yl)benzene, CAS
721969-94-4;
[0249] PD-2 is
##STR00031##
[0250] 4,4',4''-((1E,1'E,1''E)-cyclopropane-1,2,3-triylidenetris
(cyanomethanylylidene))tris(2,3,5,6-tetrafluorobenzonitrile), CAS
1224447-88-4.
[0251] LiQ is lithium 8-hydroxyquinolinolate; ZnPc is zinc
phtalocyanine;
[0252] ABH-113 is an emitter host and NUBD-370 and DB-200 are blue
fluorescent emitter dopants, all commercially available from SFC,
Korea.
[0253] ITO is indium tin oxide.
[0254] Standard Procedures
[0255] Voltage stability:
[0256] OLEDs are driven by constant current circuits. Those
circuits can supply a constant current over a given voltage range.
The wider the voltage range, the wider the power losses of such and
devices. Hence, the change of driving voltage upon driving needs to
be minimized.
[0257] The driving voltage of an OLED is temperature dependent.
Therefore, voltage stability needs to be judged in thermal
equilibrium. Thermal equilibrium is reached after one hour of
driving.
[0258] Voltage stability is measured by taking the difference of
the driving voltage after 50 hours and after 1 hour driving at a
constant current density. Here, a current density of 30 mA/cm.sup.2
is used. Measurements are done at room temperature.
[0259] dU[V]=U(50 h, 30 mA/cm.sup.2)-U(1 h, 30 mA/cm.sup.2)
EXAMPLE 1
[0260] Use of a Sulfonyl Amide coordination Complex as a Neat Hole
Injection Layer in a Blue OLED
[0261] Table 1a schematically describes the model device.
TABLE-US-00002 TABLE 1a c d Material [wt %] [nm] ITO 100 90 B2 or
E3 100 3* F1 100 120 ABH113:NUBD370 97:3 20 F2:LiQ 50:50 36 Al 100
100 *E3 has been tested also as a layer only 1 nm thin.
[0262] The results are given in Table 1b
TABLE-US-00003 TABLE 1b U* EQE* U(50 h) - U(1 h) ** [V] [%] CIE-y*
[V] 3 nm B2 5.28 6.6 0.090 0.275 (reference) 3 nm E3 5.38 5.7 0.094
0.246 1 nm E3 5.11 5.4 0.096 0.040 *j = 15 mA/cm.sup.2 ** j = 30
mA/cm.sup.2
[0263] Neat layers of E3 provide an advantage of better voltage
stability.
EXAMPLE 2
[0264] Use of a sulfonyl amide coordination complex as a p-dopant
in a hole injection layer comprised in a blue OLED
[0265] Table 2a schematically describes the model device.
TABLE-US-00004 TABLE 2a c d Material [wt %] [nm] ITO 100 90
F1:p-dopant 92:8 10 (mol %#) F1 100 120 ABH113:NUBD370 3 20 F2:LiQ
50 36 Al 100 100 #based on molar amount of metal atoms
[0266] The results are given in Table 2b
TABLE-US-00005 TABLE 2b U* EQE* U(50 h) - U(1 h) ** [V] [%] CIE-y*
[V] B2 8.06 7.1 0.095 0.639 (reference) E3 5.15 5.7 0.094 -0.015 *j
= 15 mA/cm.sup.2 ** j = 30 mA/cm.sup.2
[0267] It is shown that a p-dopant for a HIL comprising a hole
transport matrix, complex E3 is advantageous over prior art
compound B2.
[0268] Specifically, HILs p-doped with E3 provide an advantage of
better voltage stability. The higher efficiency observed with
B2-doped HIL is practically useless, due to impractically high
operational voltage of such device. In this regard, the results
show that E3 is well applicable also as a p-dopant, whereas B2 can
be used only in neat thin hole injection layers.
EXAMPLE .sub.3
[0269] Blue tandem OLED comprising a sulfonyl amide coordination
complex as a neat hole generation layer
[0270] Table 3a schematically describes the model device.
TABLE-US-00006 TABLE 3a c d Material [wt %] [nm] ITO 100 90 F1:PD-2
92:8 10 F1 100 145 ABH113:BD200 97:3 20 F3 100 25 F4:Li 99:1 10
ZnPc 100 2 p-dopant 100 1 F1 100 30 ABH113:BD200 97:3 20 F3 100 26
F4:Li 99:1 10 Al 100 100
[0271] The results are given in Table 3b
TABLE-US-00007 TABLE 3b U* EQE* [V] [%] CIE-y* 1 nm B2 10.65 6.3
0.066 (reference) 1 nm E3 7.52 13.5 0.083 *j = 10 mA/cm.sup.2 **j =
30 mA/cm.sup.2
[0272] The results show that E3 is suitable as a neat CGL, whereas
the device with a neat B2 CGL is poor.
EXAMPLE 4
[0273] Blue tandem OLED comprising a sulfonyl amide coordination
complex as a p-dopant in a hole generation layer
[0274] Table 4a schematically describes the model device.
TABLE-US-00008 TABLE 4a c d Material [wt %] [nm] ITO 100 90 F1:PD-2
92:8 10 F1 100 145 ABH113:BD200 97:3 20 F3 100 25 F4:Li 99:1 10
ZnPc 100 2 F1:p-dopant 84:16 10 (mol %)# F1 100 30 ABH113:BD200
97:3 20 F3 100 26 F4:Li 99:1 10 Al 100 100 #based on molar amount
of metal atoms
[0275] The results are given in Table 4b
TABLE-US-00009 TABLE 4b U* EQE* U(50 h) - U(1 h) ** [V] [%] CIE-y*
[V] B2 8.98 13.4 0.082 (reference) E3 7.75 14.2 0.087 0.094 *j = 10
mA/cm.sup.2 ** j = 30 mA/cm.sup.2
[0276] The results are in accordance with Example 2 showing
significantly better performance of E.sub.3 as a p-dopant in
comparison with B2.
[0277] From the foregoing detailed description and examples, it
will be evident that modifications and variations can be made to
the compositions and methods of the invention without departing
from the spirit and scope of the invention. Therefore, it is
intended that all modifications made to the invention without
departing from the spirit and scope of the invention come within
the scope of the appended claims.
* * * * *