Patent Application
20230240137
The present invention relates to an organic electronic device comprising a compound of formula (I) and a display device comprising the organic electronic device. The invention further relates to novel compounds of formula (I) which can be of use in organic electronic devices.
Organic electronic devices, such as organic light-emitting diodes OLEDs, which are self-emitting devices, have a wide viewing angle, excellent contrast, quick response, high brightness, excellent operating voltage characteristics, and color reproduction. A typical OLED comprises 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 compounds.
When a voltage is applied to the anode and the cathode, holes injected from the anode move to the EML, via the HTL, and electrons injected from the cathode 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 and/or a long lifetime.
Performance of an organic light emitting diode may be affected by characteristics of the semiconductor layer, and among them, may be affected by characteristics of compounds of formula (I) which are also contained in the semiconductor layer.
EP1988587A1 discloses as organic doping agent for the doping of an organic semiconductive matrix material, as blocker layer, as charge injection layer or as organic semiconductor itself, an organic mesomeric compound, which is an oxocarbon, pseudooxocarbon or radialene compound.
US2011127500A1 discloses an organic light-emitting diode (OLED) display apparatus and a method of manufacturing the OLED display apparatus, the apparatus includes anode electrodes having different thicknesses for different types of sub-pixels.
There remains a need to improve performance of organic semiconductor materials, semiconductor layers, as well as organic electronic devices thereof, in particular to achieve improved operating voltage stability over time through improving the characteristics of the compounds comprised therein.
An aspect of the present invention provides an organic electronic device comprising a substrate, an anode layer, a cathode layer, at least one first emission layer, and a hole injection layer, wherein the hole injection layer is arranged between the first emission layer and the anode layer, and whereby the hole injection layer comprises a compound of formula (I)
whereby A1 is selected from formula (II)
X1 is selected from CR1 or N;
X2 is selected from CR2 or N;
X3 is selected from CR3 or N;
X4 is selected from CR4 or N;
X5 is selected from CR5 or N;
R1, R2, R3, R4 and R5 (if present) are independently selected from CN, partially fluorinated or perfluorinated C1 to C8 alkyl, halogen, Cl, F, D or H, whereby when any of R1, R2, R3, R4 and R5 is present, then the corresponding X1, X2, X3, X4 and X5 is not N;
with the proviso that one of the following requirements a) to e) are fulfilled:
a) At least one R1, R2, R3, R4 and R5 is independently selected from CN, partially flurorinated or perfluorinated C1 to C8 alkyl, halogen, Cl, F, and at least one remaining R1, R2, R3, R4 and R5 is selected D or H;
b) R1 or R2 are selected from CN or partially flurorinated or perfluorinated C1 to C8 alkyl and at least one remaining R1 to R5 is independently selected from CN, partially flurorinated or perfluorinated C1 to C8 alkyl, halogen, C1 or F;
c) R3 is selected from partially flurorinated or perfluorinated C1 to C8 alkyl and at least one of R1, R2, R4 and R5 is independently selected from CN, partially flurorinated or perfluorinated C1 to C8 alkyl, halogen, C1 or F;
d) at least two R1 to R5 are independently selected from CN or partially flurorinated or perfluorinated C1 to C8 alkyl; or
A2 and A3 are independently selected from formula (III)
wherein Ar is independently selected from substituted or unsubstituted C6 to C18 aryl and substituted or unsubstituted C2 to C18 heteroaryl, wherein the substituents on Ar are independently selected from CN, partially or perfluorinated C1 to C6 alkyl, halogen, Cl, F, D; and
R′ is selected from Ar, substituted or unsubstituted C6 to C18 aryl or C3 to C18 heteroaryl, partially flurorinated or perfluorinated C1 to C8 alkyl, halogen, F or CN;
and whereby the anode layer comprises a first anode sub-layer and a second anode sub-layer, wherein
It should be noted that throughout the application and the claims any An, Bn, Rn etc. always refer to the same moieties, unless otherwise noted.
In the present specification, when a definition is not otherwise provided, “substituted” refers to one substituted with a deuterium, C1 to C12 alkyl and C1 to C12 alkoxy.
However, in the present specification “aryl substituted” refers to a substitution with one or more aryl groups, which themselves may be substituted with one or more aryl and/or heteroaryl groups.
Correspondingly, in the present specification “heteroaryl substituted” refers to a substitution with one or more heteroaryl groups, which themselves may be substituted with one or more aryl and/or heteroaryl groups.
In the present specification, when a definition is not otherwise provided, an “alkyl group” refers to a saturated aliphatic hydrocarbyl group. The alkyl group may be a C1 to C12 alkyl group. More specifically, the alkyl group may be a C1 to C10 alkyl group or a C1 to C6 alkyl group. For example, a C1 to C4 alkyl group includes 1 to 4 carbons in alkyl chain, and may be selected from methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and tert-butyl.
Specific examples of the alkyl group may be a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group.
The term “cycloalkyl” refers to saturated hydrocarbyl groups derived from a cycloalkane by formal abstraction of one hydrogen atom from a ring atom comprised in the corresponding cycloalkane. Examples of the cycloalkyl group may be a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, an adamantly group and the like.
The term “hetero” is understood the way that at least one carbon atom, in a structure which may be formed by covalently bound carbon atoms, is replaced by another polyvalent atom. Preferably, the heteroatoms are selected from B, Si, N, P, O, S; more preferably from N, P, O, S.
In the present specification, “aryl group” refers to a hydrocarbyl group which can be created by formal abstraction of one hydrogen atom from an aromatic ring in the corresponding aromatic hydrocarbon. Aromatic hydrocarbon refers to a hydrocarbon which contains at least one aromatic ring or aromatic ring system. Aromatic ring or aromatic ring system refers to a planar ring or ring system of covalently bound carbon atoms, wherein the planar ring or ring system comprises a conjugated system of delocalized electrons fulfilling Hickeys rule. Examples of aryl groups include monocyclic groups like phenyl or tolyl, polycyclic groups which comprise more aromatic rings linked by single bonds, like biphenyl, and polycyclic groups comprising fused rings, like naphtyl or fluoren-2-yl.
Analogously, under heteroaryl, it is especially where suitable understood a group derived by formal abstraction of one ring hydrogen from a heterocyclic aromatic ring in a compound comprising at least one such ring.
Under heterocycloalkyl, it is especially where suitable understood a group derived by formal abstraction of one ring hydrogen from a saturated cycloalkyl ring in a compound comprising at least one such ring.
The term “fused aryl rings” or “condensed aryl rings” is understood the way that two aryl rings are considered fused or condensed when they share at least two common sp2-hybridized carbon atoms
In the present specification, the single bond refers to a direct bond.
The term “free of”, “does not contain”, “does not comprise” does not exclude impurities which may be present in the compounds prior to deposition. Impurities have no technical effect with respect to the object achieved by the present invention.
The term “contacting sandwiched” refers to an arrangement of three layers whereby the layer in the middle is in direct contact with the two adjacent layers.
The terms “light-absorbing layer” and “light absorption layer” are used synonymously.
The terms “light-emitting layer”, “light emission layer” and “emission layer” are used synonymously.
The terms “OLED”, “organic light-emitting diode” and “organic light-emitting device” are used synonymously.
The terms “anode”, “anode layer” and “anode electrode” are used synonymously.
The terms “cathode”, “cathode layer” and “cathode electrode” are used synonymously.
In the specification, hole characteristics refer to an ability to donate an electron to form a hole when an electric field is applied and that a hole formed in the anode may be easily injected into the emission layer and transported in the emission layer due to conductive characteristics according to a highest occupied molecular orbital (HOMO) level.
In addition, electron characteristics refer to an ability to accept an electron when an electric field is applied and that electrons formed in the cathode may be easily injected into the emission layer and transported in the emission layer due to conductive characteristics according to a lowest unoccupied molecular orbital (LUMO) level.
Surprisingly, it was found that the organic electronic device according to the invention solves the problem underlying the present invention by enabling devices in various aspects superior over the organic electroluminescent devices known in the art, in particular with respect to operating voltage over lifetime.
According to one embodiment of the present invention, the first metal of the first anode sub-layer may be selected from the group comprising Ag, Mg, Al, Cr, Pt, Au, Pd, Ni, Nd, Ir, preferably Ag, Au or Al, and more preferred Ag.
According to one embodiment of the present invention, the first anode sub-layer has have a thickness in the range of 5 to 200 nm, alternatively 8 to 180 nm, alternatively 8 to 150 nm, alternatively 100 to 150 nm.
According to one embodiment of the present invention, the first anode sub-layer is formed by depositing the first metal via vacuum thermal evaporation.
It is to be understood that the first anode layer is not part of the substrate.
According to one embodiment of the present invention, the transparent conductive oxide of the second anode sub layer is selected from the group selected from the group comprising indium tin oxide or indium zinc oxide, more preferred indium tin oxide.
According to one embodiment of the present invention, the second anode sub-layer may has a thickness in the range of 3 to 200 nm, alternatively 3 to 180 nm, alternatively 3 to 150 nm, alternatively 3 to 20 nm.
According to one embodiment of the present invention, the second anode sub-layer may be formed by sputtering of the transparent conductive oxide.
According to one embodiment of the present invention, anode layer of the organic electronic device comprises in addition a third anode sub-layer comprising a transparent conductive oxide, wherein the third anode sub-layer is arranged between the substrate and the first anode sub-layer.
According to one embodiment of the present invention, the third anode sub-layer comprises a transparent oxide, preferably from the group selected from the group comprising indium tin oxide or indium zinc oxide, more preferred indium tin oxide.
According to one embodiment of the present invention, the third anode sub-layer may has a thickness in the range of 3 to 200 nm, alternatively 3 to 180 nm, alternatively 3 to 150 nm, alternatively 3 to 20 nm.
According to one embodiment of the present invention, the third anode sub-layer may be formed by sputtering of the transparent conductive oxide.
It is to be understood that the third anode layer is not part of the substrate.
According to one embodiment of the present invention, the hole injection layer is in direct contact with the anode layer.
According to one embodiment of the present invention, the hole injection layer comprises a compound of formula (IV)
whereby B1 is selected from formula (V)
B3 and B5 are Ar and B2, B4 and B6 are R′.
According to one embodiment of the present invention, at least two of the requirements a) to e) are fulfilled.
According to one embodiment of the present invention, A2 and A3 are identical
According to one embodiment of the present invention, A1 differs from A2 and A3.
According to one embodiment of the present invention, at least one from A2 and A3 is identical to A1.
According to one embodiment, the hole injection layer comprises a composition comprising a compound of formula (IV) and at least one compound of formula (IVa) to (IVd)
In case the hole injection layer comprises such a composition, throughout this application text the term “compound of formula (I)” shall also intend to include the composition as described above.
According to one embodiment of the present invention, in formula (II) at least one of X1, X2 and X3 is selected from CH.
According to one alternative embodiment of the present invention, in formula (II) two of X1, X2 and X3 are selected from CH.
According to one embodiment of the present invention, X1 and X2 are independently selected from CH or N and X3 is selected from CH.
According to one embodiment of the present invention, R1 is preferably selected from perfluorinated C1 to C6 alkyl or CN, more preferably perfluorinated C1 to C4 alkyl or CN, even more preferred CF3 or CN, further preferred CF3.
According to one embodiment of the present invention, R2 is preferably selected from perfluorinated C1 to C6 alkyl, more preferably perfluorinated C1 to C4 alkyl, even more preferred CF3.
According to one embodiment of the present invention, R3 is selected from CN, partially or fully fluorinated C1 to C4 alkyl, partially or fully fluorinated C1 to C4 alkoxy, substituted or unsubstituted C6 to C12 aryl or C3 to C12 heteroaryl, wherein the substituents are selected from halogen, F, C1, CN, partially or fully fluorinated C1 to C4 alkyl, partially or fully fluorinated C1 to C4 alkoxy; more preferred R3 is selected from CN, CF3, OCF3 or F, most preferred CN.
According to one embodiment of the present invention, R3 is selected from CN or partially flurorinated or perfluorinated C1 to C8 alkyl and one R1, R2, R4, R5 is selected from H or D; preferably R3 is selected from CN or partially flurorinated or perfluorinated C1 to C4 alkyl and one R1, R2, R4, R5 is selected from H or D; alternatively R3 is selected from CN or partially CF3 and one R1, R2, R4, R5 is selected from H or D.
According to one embodiment of the present invention, R3 is selected from CN or partially flurorinated or perfluorinated C1 to C8 alkyl and at least one R1, R2, R4, R5 is selected from H or D; preferably R3 is selected from CN or partially flurorinated or perfluorinated C1 to C4 alkyl and at least one R1, R2, R4, R5 is selected from H or D; alternatively R3 is selected from CN or partially CF3 and at least one R1, R2, R4, R5 is selected from H or D.
According to one embodiment of the present invention, R3 is selected from CN or partially flurorinated or perfluorinated C1 to C8 alkyl and two or three R1, R2, R4, R5 is selected from H or D; preferably R3 is selected from CN or partially flurorinated or perfluorinated C1 to C4 alkyl and two or three R1, R2, R4, R5 is selected from H or D; alternatively R3 is selected from CN or partially CF3 and two or three R1, R2, R4, R5 is selected from H or D.
According to one embodiment of the present invention, at least one X1 to X5 is N and at least one R1 to R5 is selected from CN, partially flurorinated or perfluorinated C1 to C8 alkyl, halogen, C1, F.
According to one embodiment of the present invention, Ar is selected from substituted or unsubstituted C6 to C12 aryl and substituted or unsubstituted C3 to C12 heteroaryl, wherein the substituents on Ar are independently selected from CN, partially or perfluorinated C1 to C4 alkyl, halogen, F; preferably Ar is selected from substituted phenyl, pyridyl, pyrimidyl or triazinyl, wherein the substituents on Ar are independently selected from CN, CF3 or F.
According to one embodiment of the present invention, A2 is selected from formula (IIIa)
and A3 is selected from formula (III).
According to one alternative embodiment of the present invention, A2 and A3 are independently selected from formula (Ma).
According to one embodiment of the present invention, A1, A2 and A3 are selected the same.
According to one embodiment of the present invention, A2 and A3 are selected the same and A′ is selected differently from A2 and A3.
According to one embodiment of the present invention, A1 and A2 are selected the same and A3 is selected differently from A1 and A2.
According to one embodiment of the present invention, R′ is CN.
According to one embodiment of the present invention, formula (II) is selected from the group comprising the following moieties:
According to one embodiment of the present invention, formula (II) is selected from the group comprising the following moieties:
According to one embodiment of the present invention, formula (III) is selected from the group comprising the following moieties:
According to one embodiment of the present invention, formula (III) is selected from the group comprising the following moieties:
According to one embodiment of the present invention, formula (III) is selected from the group comprising the following moieties:
According to one embodiment of the present invention, the compound of formula (I) comprises less than nine CN groups, preferably less than eight CN groups.
According to one embodiment of the present invention, the compound of formula (I) comprises between three and eight CN groups, preferably between three and seven CN groups.
When the number of CN groups in the compound of formula (I) is selected in this range, improved processing properties, in particular in vacuum thermal deposition, may be obtained.
According to one embodiment of the present invention, the LUMO level of compound of formula (I) is selected in the range of ≤−4.3 eV and ≥−5.6 eV when calculated with the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany) by applying the hybrid functional B3LYP with a 6-31G* basis set in the gas phase, preferably in the range of ≤−4.35 eV and ≥−5.4 eV and most preferred in the range of ≤−4.35 eV and ≥−5.15 eV.
According to one embodiment of the present invention, the hole injection layer comprises a compound selected from A1 to A37:
According to one embodiment of the present invention the hole injection layer and/or the compound of formula (I) are non-emissive.
In the context of the present specification the term “essentially non-emissive” or “non-emissive” means that the contribution of the compound or layer to the visible emission spectrum from the device is less than 10%, preferably less than 5% relative to the visible emission spectrum. The visible emission spectrum is an emission spectrum with a wavelength of about ≥380 nm to about ≤780 nm.
The present invention furthermore relates to a compound of formula (I) of claim 1, wherein formula (III) is selected from the group consisting of
According to an embodiment of the present invention, the hole injection layer comprises a substantially covalent matrix compound.
According to one embodiment the substantially covalent matrix compound may be selected from at least one organic compound, which may consists substantially from covalently bound C, H, O, N, S, which optionally comprise in addition covalently bound B, P, As and/or Se.
Organometallic compounds comprising covalent bonds carbon-metal, metal complexes comprising organic ligands and metal salts of organic acids are further examples of organic compounds that may serve as substantially covalent matrix compound of the hole injection layer.
In one embodiment, the substantially covalent matrix compound lacks metal atoms and majority of its skeletal atoms may be selected from C, O, S, N. Alternatively, the substantially covalent matrix compound lacks metal atoms and majority of its skeletal atoms may be selected from C and N.
According to one embodiment, the substantially covalent matrix compound may have a molecular weight Mw of ≥400 and ≤2000 g/mol, preferably a molecular weight Mw of ≥450 and ≤1500 g/mol, further preferred a molecular weight Mw of ≥500 and ≤1000 g/mol, in addition preferred a molecular weight Mw of ≥550 and ≤900 g/mol, also preferred a molecular weight Mw of ≥600 and ≤800 g/mol.
Preferably, the substantially covalent matrix compound comprises at least one arylamine moiety, alternatively a diarylamine moiety, alternatively a triarylamine moiety.
Preferably, the substantially covalent matrix compound is free of metals and/or ionic bonds.
Compound of formula (VI) or a compound of formula (VII)
According to another aspect of the present invention, the substantially covalent matrix compound may comprise at least one arylamine compound, diarylamine compound, triarylamine compound, a compound of formula (VI) or a compound of formula (VII):
wherein:
T1, T2, T3, T4 and T5 are independently selected from a single bond, phenylene, biphenylene, terphenylene or naphthenylene, preferably a single bond or phenylene;
T6 is phenylene, biphenylene, terphenylene or naphthenylene;
Ar1, Ar2, Ar3, Ar4 and Ary are independently selected from substituted or unsubstituted C6 to C20 aryl, or substituted or unsubstituted C3 to C20 heteroarylene, substituted or unsubstituted biphenylene, substituted or unsubstituted fluorene, substituted 9-fluorene, substituted 9,9-fluorene, substituted or unsubstituted naphthalene, substituted or unsubstituted anthracene, substituted or unsubstituted phenanthrene, substituted or unsubstituted pyrene, substituted or unsubstituted perylene, substituted or unsubstituted triphenylene, substituted or unsubstituted tetracene, substituted or unsubstituted tetraphene, substituted or unsubstituted dibenzofurane, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted xanthene, substituted or unsubstituted carbazole, substituted 9-phenylcarbazole, substituted or unsubstituted azepine, substituted or unsubstituted dibenzo[b,f]azepine, substituted or unsubstituted 9,9′-spirobi[fluorene], substituted or unsubstituted spiro[fluorene-9,9′-xanthene], or a substituted or unsubstituted aromatic fused ring system comprising at least three substituted or unsubstituted aromatic rings selected from the group comprising substituted or unsubstituted non-hetero, substituted or unsubstituted hetero 5-member rings, substituted or unsubstituted 6-member rings and/or substituted or unsubstituted 7-member rings, substituted or unsubstituted fluorene, or a fused ring system comprising 2 to 6 substituted or unsubstituted 5- to 7-member rings and the rings are selected from the group comprising (i) unsaturated 5- to 7-member ring of a heterocycle, (ii) 5- to 6-member of an aromatic heterocycle, (iii) unsaturated 5- to 7-member ring of a non-heterocycle, (iv) 6-member ring of an aromatic non-heterocycle;
wherein
the substituents of Ar1, Ar2, Ar3, Ar4 and Ar5 are selected the same or different from the group comprising H, D, F, C(—O)R2, CN, Si(R2)3, P(—O)(R2)2, OR2, S(—O)R2, S(—O)2R2, substituted or unsubstituted straight-chain alkyl having 1 to 20 carbon atoms, substituted or unsubstituted branched alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cyclic alkyl having 3 to 20 carbon atoms, substituted or unsubstituted alkenyl or alkynyl groups having 2 to 20 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms, substituted or unsubstituted aromatic ring systems having 6 to 40 aromatic ring atoms, and substituted or unsubstituted heteroaromatic ring systems having 5 to 40 aromatic ring atoms, unsubstituted C6 to C18 aryl, unsubstituted C3 to C18 heteroaryl, a fused ring system comprising 2 to 6 unsubstituted 5- to 7-member rings and the rings are selected from the group comprising unsaturated 5- to 7-member ring of a heterocycle, 5- to 6-member of an aromatic heterocycle, unsaturated 5- to 7-member ring of a non-heterocycle, and 6-member ring of an aromatic non-heterocycle,
wherein R2 may be selected from H, D, straight-chain alkyl having 1 to 6 carbon atoms, branched alkyl having 1 to 6 carbon atoms, cyclic alkyl having 3 to 6 carbon atoms, alkenyl or alkynyl groups having 2 to 6 carbon atoms, C6 to C18 aryl or C3 to C18 heteroaryl.
According to an embodiment wherein T1, T2, T3, T4 and T5 may be independently selected from a single bond, phenylene, biphenylene or terphenylene. According to an embodiment wherein T1, T2, T3, T4 and T5 may be independently selected from phenylene, biphenylene or terphenylene and one of T1, T2, T3, T4 and T5 are a single bond. According to an embodiment wherein T1, T2, T3, T4 and T5 may be independently selected from phenylene or biphenylene and one of T1, T2, T3, T4 and T5 are a single bond. According to an embodiment wherein T1, T2, T3, T4 and T5 may be independently selected from phenylene or biphenylene and two of T1, T2, T3, T4 and T5 are a single bond.
According to an embodiment wherein T1, T2 and T3 may be independently selected from phenylene and one of T1, T2 and T3 are a single bond. According to an embodiment wherein T1, T2 and T3 may be independently selected from phenylene and two of T1, T2 and T3 are a single bond.
According to an embodiment wherein T6 may be phenylene, biphenylene, terphenylene. According to an embodiment wherein T6 may be phenylene. According to an embodiment wherein T6 may be biphenylene. According to an embodiment wherein T6 may be terphenylene.
According to an embodiment wherein Ar1, Ar2, Ar3, Ar4 and Ar5 may be independently selected from D1 to D16:
wherein the asterix “*” denotes the binding position.
According to an embodiment, wherein Ar′, Ar2, Ar3, Ar4 and Ar5 may be independently selected from D1 to D15; alternatively selected from D1 to D10 and D13 to D15.
According to an embodiment, wherein Ar′, Ar2, Ar3, Ar4 and Ar5 may be independently selected from the group consisting of D1, D2, D5, D7, D9, D10, D13 to D16.
The rate onset temperature may be in a range particularly suited to mass production, when Ar1, Ar2, Ar3, Ar4 and Ar5 are selected in this range.
According to one embodiment, the substantially covalent matrix compound comprises at least one naphthyl group, carbazole group, dibenzofurane group, dibenzothiophene group and/or substituted fluorenyl group, wherein the substituents are independently selected from methyl, phenyl or fluorenyl.
According to an embodiment of the invention, the substantially covalent matrix compound comprises a compound selected from F1 to F18:
According to one embodiment of the invention the electronic organic device is an electroluminescent device, preferably an organic light emitting diode.
According to one embodiment of the invention, the electronic organic device is not an organic light emitting diode comprising a substrate, an anode, a cathode, a first emission layer, an electron injection layer and a second electron transport layer stack, wherein the second electron transport layer stack is arranged between the first emission layer and the electron injection layer;
wherein
wherein each C6 to C12 aryl substituent on X and each C3 to C11 heteroaryl substituent on X may be substituted with C1 to C4 alkyl or halogen;
The present invention furthermore relates to a display device comprising an organic electronic device according to the present invention.
Further Layers
In accordance with the invention, the organic electronic device may comprise, besides the layers already mentioned above, further layers. Exemplary embodiments of respective layers are described in the following:
Substrate
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.
Hole Transport Layer
According to one embodiment of the present invention, the whereby the organic electronic device comprises a hole transport layer, wherein the hole transport layer is arranged between the hole injection layer and the at least one first emission layer.
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.
The HTL may be formed of 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.
According to one embodiment of the present invention, the hole transport layer may comprise a substantially covalent matrix compound as described above.
According to one embodiment of the present invention, the hole transport layer may comprise a compound of formula (VI) or (VII) as described above.
According to one embodiment of the present invention, the hole injection layer and the hole transport layer comprises the same substantially covalent matrix compound as described above.
According to one embodiment of the present invention, the hole injection layer and the hole transport layer comprises the same compound of formula (VI) or (VII) as described above.
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.
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.
Electron Blocking Layer
The function of an electron blocking layer (EBL) is to prevent electrons from being transferred from an 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 selected between 2 and 20 nm.
If the electron blocking layer has a high triplet level, it may also be described as triplet control layer.
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.
Emission Layer (EMI)
The EML may be formed on the HTL by vacuum deposition, spin coating, slot-die coating, printing, casting, LB 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.
According to one embodiment of the present invention, the emission layer does not comprise the compound of formula (I).
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) and bis(2-(2-hydroxyphenyl)benzo-thiazolate)zinc (Zn(BTZ)2).
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.
Examples of red emitter dopants are PtOEP, Ir(piq)3, and Btp21r(acac), but are not limited thereto. These compounds are phosphorescent emitters, however, fluorescent red emitter dopants could also be used.
Examples of phosphorescent green emitter dopants are Ir(ppy)3 (ppy=phenylpyridine), Ir(ppy)2(acac), Ir(mpyp)3.
Examples of phosphorescent blue emitter dopants are F2Irpic, (F2ppy)2Ir(tmd) and Ir(dfppz)3 and ter-fluorene. 4. 4′-bis(4-diphenyl amiostyryl)biphenyl (DPAVBi), 2,5,8,11-tetra-tert-butyl perylene (TBPe) are examples of fluorescent blue emitter dopants.
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.
Hole Blocking Layer (HBL)
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.
The HBL may also be named auxiliary ETL or a-ETL.
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, phenanthroline derivatives and azine derivatives, preferably triazine or pyrimidine derivatives.
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.
Electron Transport Layer (ETL)
The organic electronic device according to the present invention may further comprise an electron transport layer (ETL).
According to another embodiment of the present invention, the electron transport layer may further comprise an azine compound, preferably a triazine compound.
In one embodiment, the electron transport layer may further comprise a dopant selected from an alkali organic complex, preferably LiQ.
The thickness of the ETL may be in the range from about 15 nm to about 50 nm, for example, in the range from about 20 nm to about 40 nm. When the thickness of the EIL is within this range, the ETL may have satisfactory electron-injecting properties, without a substantial penalty in driving voltage.
According to another embodiment of the present invention, the organic electronic device may further comprise a hole blocking layer and an electron transport layer, wherein the hole blocking layer and the electron transport layer comprise an azine compound. Preferably, the azine compound is a triazine compound.
Electron Injection Layer (EIL)
An 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, Li2O, 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.
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.
Cathode Layer
The cathode layer is formed on the ETL or optional EIL. The cathode layer 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 layer 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 oxide, such as ITO or IZO.
The thickness of the cathode layer 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 layer is in the range from about 5 nm to about 50 nm, the cathode layer may be transparent or semitransparent even if formed from a metal or metal alloy.
It is to be understood that the cathode layer is not part of an electron injection layer or the electron transport layer.
Organic Light-Emitting Diode (OLED)
The organic electronic device according to the invention may be an organic light-emitting device.
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 comprising a compound of formula (I), a hole transport layer, an emission layer, an electron transport layer and a cathode electrode.
According to another aspect of the present invention, there is provided an OLED comprising: a substrate; an anode electrode formed on the substrate; a hole injection layer comprising a compound of formula (I), a hole transport layer, an electron blocking layer, an emission layer, a hole blocking layer, an electron transport layer and a cathode electrode.
According to another aspect of the present invention, there is provided an OLED comprising: a substrate; an anode electrode formed on the substrate; a hole injection layer comprising a compound of formula (I), a hole transport layer, an electron blocking layer, an emission layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode electrode.
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.
According to one aspect, the OLED may 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.
For example, the OLED according to
Organic Electronic Device
The organic electronic device according to the invention may be a light emitting device, or a photovoltaic cell, and preferably a light emitting device.
According to another aspect of the present invention, there is provided a method of manufacturing an organic electronic device, the method using:
The methods for deposition that can be suitable comprise:
According to various embodiments of the present invention, there is provided a method using:
According to various embodiments of the present invention, the method may further include forming on the anode electrode, at least one layer selected from the group consisting of forming a hole transport layer or forming a hole blocking layer, and an emission layer between the anode electrode and the first electron transport layer.
According to various embodiments of the present invention, the method may further include the steps for forming an organic light-emitting diode (OLED), wherein
According to various embodiments, the OLED may have the following layer structure, wherein the layers having the following order:
anode, hole injection layer comprising a compound of formula (I) according to the invention, first hole transport layer, second hole transport layer, emission layer, optional hole blocking layer, electron transport layer, optional electron injection layer, and cathode.
According to another aspect of the invention, it is provided an electronic device comprising at least one organic light emitting device according to any embodiment described throughout this application, preferably, the electronic device comprises the organic light emitting diode in one of embodiments described throughout this application. More preferably, the electronic device is a display device.
Hereinafter, the embodiments are illustrated in more detail with reference to examples. However, the present disclosure is not limited to the following examples. Reference will now be made in detail to the exemplary aspects.
The aforementioned components, as well as the claimed components and the components to be used in accordance with the invention in the described embodiments, are not subject to any special exceptions with respect to their size, shape, material selection and technical concept such that the selection criteria known in the pertinent field can be applied without limitations.
Additional details, characteristics and advantages of the object of the invention are disclosed in the dependent claims and the following description of the respective figures which in an exemplary fashion show preferred embodiments according to the invention. Any embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims and herein for interpreting the scope of the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention as claimed.
Hereinafter, the
Herein, when a first element is referred to as being formed or disposed “on” or “onto” 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” or “directly onto” a second element, no other elements are disposed there between.
(HTL) (140), a first emission layer (EML) (150), a hole blocking layer (HBL) (155), an electron transport layer (ETL) (160), and a cathode layer (190) are disposed.
While not shown in
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.
The invention is furthermore illustrated by the following examples which are illustrative only and non-binding.
Compounds of formula (I) may be prepared as described in EP2180029A1 and
The HOMO and LUMO are calculated with the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany). The optimized geometries and the HOMO and LUMO energy levels of the molecular structures are determined by applying the hybrid functional B3LYP with a 6-31G* basis set in the gas phase. If more than one conformation is viable, the conformation with the lowest total energy is selected.
For Examples 1 to 16 and comparative example 2 in Table 2, a glass substrate with an anode layer comprising a first anode sub-layer of 120 nm Ag, a second anode sub-layer of 8 nm ITO and a third anode sub-layer of 10 nm ITO was cut to a size of 50 mm×50 mm×0.7 mm, ultrasonically washed with water for 60 minutes and then with isopropanol for 20 minutes. The liquid film was removed in a nitrogen stream, followed by plasma treatment, see Table 2, to prepare the anode layer. The plasma treatment was performed in nitrogen atmosphere or in an atmosphere comprising 97.6 vol.-% nitrogen and 2.4 vol.-% oxygen.
Then, compound of formula F3 as matrix compound and compound of formula (I) were co-deposited in vacuum on the anode layer, to form a hole injection layer (HIL) having a thickness of 10 nm. The percentage compound of formula (I) in the HIL can be seen in Table 2.
Then, compound of formula F3 was vacuum deposited on the HIL, to form a HTL having a thickness of 123 nm.
Then N-([1,1′-biphenyl]-4-yl)-9,9-diphenyl-N-(4-(triphenylsilyl)phenyl)-9H-fluoren-2-amine (CAS 1613079-70-1) was vacuum deposited on the HTL, to form an electron blocking layer (EBL) having a thickness of 5 nm.
Then 97 vol.-% H09 (Sun Fine Chemicals, Korea) as EML host and 3 vol.-% BD200 (Sun Fine Chemicals, Korea) as fluorescent blue emitter dopant were deposited on the EBL, to form a blue-emitting first emission layer (EML) with a thickness of 20 nm.
Then a hole blocking layer was formed with a thickness of 5 nm by depositing 2-(3′-(9,9-dimethyl-9H-fluoren-2-yl)[1,1′-biphenyl]-3-yl)-4,6-diphenyl-1,3,5-triazine on the emission layer EML.
Then the electron transporting layer having a thickness of 31 nm was formed on the hole blocking layer by depositing 50 wt. -% 4′-(4-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)naphthalen-1-yl)-[1,1′-biphenyl]-4-carbonitrile and 50 wt. -% of LiQ.
Then Ag:Mg (90:10 vol.-%) was evaporated at a rate of 0.01 to 1 Å/s at 10−7 mbar to form a cathode layer with a thickness of 13 nm on the electron transporting layer.
Then, compound of formula F3 was deposited on the cathode layer to form a capping layer with a thickness of 75 nm.
For comparative example 1 in Table 3, a 15Ω/cm2 glass substrate with 90 nm ITO (available from Corning Co.) was cut to a size of 50 mm×50 mm×0.7 mm, ultrasonically washed with water for 60 minutes and then with isopropanol for 20 minutes. The liquid film was removed in a nitrogen stream, followed by plasma treatment in nitrogen atmosphere at a power of 100 W for 75 seconds to prepare the anode layer.
Then, 92 wt.-% compound of formula F3 and 8 wt.-% compound A8 were co-deposited in vacuum on the anode layer, to form a hole injection layer (HIL) having a thickness of 10 nm.
Then, compound of formula F3 was vacuum deposited on the HIL, to form a HTL having a thickness of 123 nm.
Then, the EBL, EML, HBL and ETL are deposited in this order on the HTL, as described for example 1 above.
Then Yb was evaporated at a rate of 0.01 to 1 Å/s at 10−7 mbar to form an electron injection layer with a thickness of 2 nm on the electron transporting layer.
Then A1 was evaporated at a rate of 0.01 to 1 Å/s at 10−7 mbar to form a cathode layer with a thickness of 100 nm on the electron injection layer.
The OLED stack is protected from ambient conditions by encapsulation of the device with a glass slide. Thereby, a cavity is formed, which includes a getter material for further protection.
To assess the performance of the inventive examples compared to the prior art, the current efficiency is measured at 20° C. The current-voltage characteristic is determined using a Keithley 2635 source measure unit, by sourcing an operating voltage U in V and measuring the current in mA flowing through the device under test. The voltage applied to the device is varied in steps of 0.1V in the range between 0 V and 10 V.
In Table 1 are shown LUMO levels for Examples A1 to A37 and comparative example 1 (═C1). As comparative compound (referred to as C1) a compound with A1 to A3=Phenyl and R′ ═CN was used.
LUMO levels were calculated with the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany) by applying the hybrid functional B3LYP with a 6-31G* basis set in the gas phase.
Table 2 shows the setup and the operating voltage of one device according to comparative examples 1 and 2 and to examples 1 to 16 according to the invention:
A low operating voltage U may be beneficial for reduced power consumption and improved battery life, in particular in mobile devices.
The particular combinations of elements and features in the above detailed embodiments are exemplary only; the interchanging and substitution of these teachings with other teachings in this and the patents/applications incorporated by reference are also expressly contemplated. As those skilled in the art will recognize, variations, modifications, and other implementations of what is described herein can occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the foregoing description is by way of example only and is not intended as limiting. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The invention's scope is defined in the following claims and the equivalents thereto. Furthermore, reference signs used in the description and claims do not limit the scope of the invention as claimed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20181386.2 | Jun 2020 | EP | regional |
| 20181398.7 | Jun 2020 | EP | regional |
| 20181408.4 | Jun 2020 | EP | regional |
| 20203447.6 | Oct 2020 | EP | regional |
| 20203457.5 | Oct 2020 | EP | regional |
| 20203458.3 | Oct 2020 | EP | regional |
| 20203460.9 | Oct 2020 | EP | regional |
| 20203463.3 | Oct 2020 | EP | regional |
| PCT/EP2021/065949 | Jun 2021 | WO | international |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/066602 | 6/18/2021 | WO |
