Patent Description:
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.

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 metal complexes which are also contained in the semiconductor layer.

<CIT> discloses an organic semiconductor material and a luminescent device. The organic semiconductor material comprises atleast one substrate material and at least one doping material. The substrate materials are provided with structures shown as the general formula
<CHM>
and the doping materials are provided with structures shown as the general formula
<CHM>.

<CIT> discloses an organic light emitting device and relates to the technical field of organic electroluminescence. The organic light-emitting device is obtained by combining the different compounds of the chemical formulas
<CHM>
to have the first hole transport layer and the second hole transport layer.

Further materials are disclosed in the <CIT>.

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 an anode layer, a cathode layer and at least one organic semiconductor layer, wherein the at least one organic semiconductor layer is arranged between the anode layer and the cathode layer; and wherein the at least one organic semiconductor layer comprises a compound of formula (I)
<CHM>
whereby A<NUM> is selected from formula (II)
<CHM>
whereby.

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, C<NUM> to C<NUM> alkyl and C<NUM> to C<NUM> 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 C<NUM> to C<NUM> alkyl group. More specifically, the alkyl group may be a C<NUM> to C<NUM> alkyl group or a C<NUM> to C<NUM> alkyl group. For example, a C<NUM> to C<NUM> alkyl group includes <NUM> to <NUM> 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 Hückel's 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-<NUM>-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 sp<NUM>-hybridized carbon atoms.

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 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 compound is selected of the formula (IV)
<CHM>
whereby B<NUM> is selected from formula (V)
<CHM>
B<NUM> and B<NUM> are Ar and B<NUM>, B<NUM> and B<NUM> are R<NUM>.

According to one embodiment, the organic semiconductor layer comprises a composition comprising a compound of formula (IV) and at least one compound of formula (IVa) to (IVd)
<CHM>
<CHM>
<CHM>
<CHM>.

In case the organic semiconductor 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, R<NUM> is preferably selected from perfluorinated C<NUM> to C<NUM> alkyl or CN, more preferably perfluorinated C<NUM> to C<NUM> alkyl or CN, even more preferred CF<NUM> or CN, further preferred CF<NUM>.

According to one embodiment of the present invention, R<NUM> is preferably selected from perfluorinated C<NUM> to C<NUM> alkyl, more preferably perfluorinated C<NUM> to C<NUM> alkyl, even more preferred CF<NUM>.

According to the present invention, R<NUM> is selected from CN.

According to one embodiment of the present invention, at least one from A<NUM> and A<NUM> is identical to A<NUM>.

According to the present invention, in formula (II) at least one of X<NUM>, X<NUM> and X<NUM> is selected from CH.

According to one alternative embodiment of the present invention, in formula (II) two of X<NUM>, X<NUM> and X<NUM> are selected from CH.

According to one embodiment of the present invention, X<NUM> and X<NUM> are independently selected from CH or N and X<NUM> is selected from CH.

According to one embodiment of the present invention, Ar is selected from substituted or unsubstituted C<NUM> to C<NUM> aryl and substituted or unsubstituted C<NUM> to C<NUM> heteroaryl, wherein the substituents on Ar are independently selected from CN, partially or perfluorinated C<NUM> to C<NUM> alkyl, halogen, F; preferably Ar is selected from substituted phenyl, pyridyl, pyrimidyl or triazinyl, wherein the susbstituents on Ar are independently selected from CN, CF<NUM> or F.

According to one embodiment of the present invention, A<NUM> is selected from formula (IIIa)
<CHM>
and A<NUM> is selected from formula (III).

According to one alternative embodiment of the present invention, A<NUM> and A<NUM> are independently selected from formula (IIIa).

According to one embodiment of the present invention, A<NUM>, A<NUM> and A<NUM> are selected the same.

According to one embodiment of the present invention, A<NUM> and A<NUM> are selected the same and A<NUM> is selected differently from A<NUM> and A<NUM>.

According to one embodiment of the present invention, formula (II) is selected from the group comprising the following moieties:
<CHM>
<CHM>
<CHM>.

According to one embodiment of the present invention, formula (III) is selected from the group comprising the following moieties:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

According to one embodiment of the present invention, the LUMO level of compound of formula (I) is selected in the range of ≤ -<NUM> eV and ≥ -<NUM> eV when calculated with the program package TURBOMOLE V6. <NUM> (TURBOMOLE GmbH, Litzenhardtstrasse <NUM>, <NUM> Karlsruhe, Germany) by applying the hybrid functional B3LYP with a <NUM>-<NUM>* basis set in the gas phase, preferably in the range of ≤ -<NUM> eV and ≥ -<NUM> eV and most preferred in the range of ≤ -<NUM> eV and ≥ -<NUM> eV.

According to one embodiment, compound of formula (I) is selected from the compounds A1 to A7 and A9 to A12 (compound A8 is not forming part of the claimed invention). <CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

According to one embodiment of the present invention the organic semiconductor 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 <NUM> %, preferably less than <NUM> % relative to the visible emission spectrum. The visible emission spectrum is an emission spectrum with a wavelength of about ≥ <NUM> to about ≤ <NUM>.

According to one embodiment of the invention, the at least one organic semiconductor layer further comprises a substantially covalent matrix compound.

The organic semiconductor layer may further comprises a substantially covalent matrix compound. According to one embodiment the substantially covalent matrix compound may be selected from at least one organic compound. The substantially covalent matrix may consists substantially from covalently bound C, H, O, N, S, which optionally comprise in addition covalently bound B, P, As and/or Se.

According to one embodiment of the organic electronic device, the organic semiconductor layer further comprises a substantially covalent matrix compound, wherein the substantially covalent matrix compound may be selected from organic compounds consisting 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 compounds 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 ≥ <NUM> and ≤ <NUM>/mol, preferably a molecular weight Mw of ≥ <NUM> and ≤ <NUM>/mol, further preferred a molecular weight Mw of ≥ <NUM> and ≤ <NUM>/mol, in addition preferred a molecular weight Mw of ≥ <NUM> and ≤ <NUM>/mol, also preferred a molecular weight Mw of ≥ <NUM> and ≤ <NUM>/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.

According to another aspect of the present invention, the at least one matrix compound, also referred to as "substantially covalent matrix compound", may comprises at least one arylamine compound, diarylamine compound, triarylamine compound, a compound of formula (VI) or a compound of formula (VII):
<CHM>
wherein:.

According to an embodiment wherein T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> may be independently selected from a single bond, phenylene, biphenylene or terphenylene. According to an embodiment wherein T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> may be independently selected from phenylene, biphenylene or terphenylene and one of T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> are a single bond. According to an embodiment wherein T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> may be independently selected from phenylene or biphenylene and one of T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> are a single bond. According to an embodiment wherein T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> may be independently selected from phenylene or biphenylene and two of T<NUM>, T<NUM>, T<NUM>, T<NUM> and T<NUM> are a single bond.

According to an embodiment wherein T<NUM>, T<NUM> and T<NUM> may be independently selected from phenylene and one of T<NUM>, T<NUM> and T<NUM> are a single bond. According to an embodiment wherein T<NUM>, T<NUM> and T<NUM> may be independently selected from phenylene and two of T<NUM>, T<NUM> and T<NUM> are a single bond.

According to an embodiment wherein T<NUM> may be phenylene, biphenylene, terphenylene. According to an embodiment wherein T<NUM> may be phenylene. According to an embodiment wherein T<NUM> may be biphenylene. According to an embodiment wherein T<NUM> may be terphenylene.

According to an embodiment wherein Ar<NUM>, Ar<NUM>, Ar<NUM>, Ar<NUM> and Ar<NUM> may be independently selected from D1 to D16:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
wherein the asterix "*" denotes the binding position.

According to an embodiment, wherein Ar<NUM>, Ar<NUM>, Ar<NUM>, Ar<NUM> and Ar<NUM> may be independently selected from D1 to D15; alternatively selected from D1 to D10 and D13 to D15.

According to an embodiment, wherein Ar<NUM>, Ar<NUM>, Ar<NUM>, Ar<NUM> and Ar<NUM> 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 Ar<NUM>, Ar<NUM>, Ar<NUM>, Ar<NUM> and Ar<NUM> are selected in this range.

The "matrix compound of formula (VI) or formula (VII)" may be also referred to as "hole transport compound".

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 electronic device, wherein the matrix compound of formula (VI) or formula (VII) are selected from F1 to F18:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The organic semiconductor layer may be formed on the anode layer or cathode layer by vacuum deposition, spin coating, printing, casting, slot-die coating, Langmuir-Blodgett (LB) deposition, or the like. When the Organic semiconductor layer is formed using vacuum deposition, the deposition conditions may vary according to the compound(s) that are used to form the layer, and the desired structure and thermal properties of the layer. In general, however, conditions for vacuum deposition may include a deposition temperature of <NUM>° C to <NUM>° C, a pressure of <NUM>-<NUM> to <NUM>-<NUM> Torr (<NUM> Torr equals <NUM> Pa), and a deposition rate of <NUM> to <NUM>/sec.

When the organic semiconductor layer is formed using spin coating or printing, coating conditions may vary according to the compound(s) that are used to form the layer, and the desired structure and thermal properties of the organic semiconductor layer. For example, the coating conditions may include a coating speed of about <NUM> rpm to about <NUM> rpm, and a thermal treatment temperature of about <NUM>° C to about <NUM>° C. Thermal treatment removes a solvent after the coating is performed.

The thickness of the organic semiconductor layer may be in the range from about <NUM> to about <NUM>, and for example, from about <NUM> to about <NUM>, alternatively about <NUM> to about <NUM>.

When the thickness of the organic semiconductor layer is within this range, the organic semiconductor layer may have excellent hole injecting and/or hole generation characteristics, without a substantial penalty in driving voltage.

According to one embodiment of the present invention, the organic semiconductor layer may comprise:.

According to one embodiment of the invention, the organic electronic device comprises at least one photoactive layer and the at least one of the at least one organic semiconductor layers is arranged between the anode and the at least one photoactive layer.

According to one embodiment of the invention, the organic electronic device comprises at least two photoactive layers, wherein at least one of the at least one organic semiconductor layers is arranged between the first and the second photoactive layer.

According to one embodiment of the invention, the organic electronic devices comprises at least one photoactive layer, wherein the photoactive layer is arranged between the anode layer and the cathode layer.

According to one embodiment of the invention, the organic electronic devices comprises at least one photoactive layer and the at least one organic semiconductor layers is arranged between the anode and the at least one photoactive layer.

According to one embodiment of the invention, the organic electronic device comprises at least two photoactive layers, wherein one of the at least one organic semiconductor layers is arranged between the first and the second photoactive layer and one of the at least one organic semiconductor layers is arranged between the anode layer and the first photoactive layer.

According to one embodiment of the invention the electronic organic device is an electroluminescent device, preferably an organic light emitting diode.

The present invention furthermore relates to a display device comprising an organic electronic device according to the present invention.

The present invention furthermore relates to a compound of formula (I)
<CHM>
whereby A<NUM> is selected from formula (II)
<CHM>
whereby.

Any specifications of formula (I) as described above in the context of the organic electronic device apply mutatis mutandis.

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:.

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.

The anode layer may be formed by depositing or sputtering a material that is used to form the anode layer. The material used to form the anode layer 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 layer may also be formed using metals, typically silver (Ag), gold (Au), or metal alloys.

A hole injection layer (HIL) may be formed on the anode layer 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 <NUM>° C to <NUM>° C, a pressure of <NUM>-<NUM> to <NUM>-<NUM> Torr (<NUM> Torr equals <NUM> Pa), and a deposition rate of <NUM> to <NUM>/sec.

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 <NUM> rpm to about <NUM> rpm, and a thermal treatment temperature of about <NUM>° C to about <NUM>° C. Thermal treatment removes a solvent after the coating is performed.

The HIL may be formed 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), <NUM>,<NUM>',<NUM>"-tris (<NUM>-methylphenylphenylamino) triphenylamine (m-MTDATA), TDATA, 2T-NATA, polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), poly(<NUM>,<NUM>-ethylenedioxythiophene)/poly(<NUM>-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (Pani/CSA), and polyaniline)/poly(<NUM>-styrenesulfonate (PANI/PSS).

The HIL may comprise or consist of p-type dopant and the p-type dopant may be selected from tetrafluoro-tetracyanoquinonedimethane (F4TCNQ), <NUM>,<NUM>'-(perfluoronaphthalen-<NUM>,<NUM>-diylidene) dimalononitrile or <NUM>,<NUM>',<NUM>"-(cyclopropane-<NUM>,<NUM>,<NUM>-triylidene)tris(<NUM>-(p-cyanotetrafluorophenyl)acetonitrile) but not limited hereto. The HIL may be selected from a hole-transporting matrix compound doped with a p-type dopant. Typical examples of known doped hole transport materials are: copper phthalocyanine (CuPc), which HOMO level is approximately -<NUM> eV, doped with tetrafluoro-tetracyanoquinonedimethane (F4TCNQ), which LUMO level is about -<NUM> eV; zinc phthalocyanine (ZnPc) (HOMO = -<NUM> eV) doped with F4TCNQ; α-NPD (N,N'-Bis(naphthalen-<NUM>-yl)-N,N'-bis(phenyl)-benzidine) doped with F4TCNQ. α-NPD doped with <NUM>,<NUM>'-(perfluoronaphthalen-<NUM>,<NUM>-diylidene) dimalononitrile. The p-type dopant concentrations can be selected from <NUM> to <NUM> wt. -%, more preferably from <NUM> wt. -% to <NUM> wt.

The thickness of the HIL may be in the range from about <NUM> to about <NUM>, and for example, from about <NUM> to about <NUM>. 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.

A 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 <NPL> 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(<NUM>-methylphenyl)-N,N'-diphenyl-[<NUM>,<NUM>-biphenyl]-<NUM>,<NUM>'-diamine (TPD), or N,N'-di(naphthalen-<NUM>-yl)-N,N'-diphenyl benzidine (alpha-NPD); and triphenylamine-based compound, such as <NUM>,<NUM>',<NUM>"-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 the same substantially covalent matrix compound as the Organic semiconductor layer.

The thickness of the HTL may be in the range of about <NUM> to about <NUM>, preferably, about <NUM> to about <NUM>, further about <NUM> to about <NUM>, further about <NUM> to about <NUM>, further about <NUM> to about <NUM>, further about <NUM> to about <NUM>, further about <NUM> to about <NUM>, further about <NUM> to about <NUM>. A preferred thickness of the HTL may be <NUM> to <NUM>.

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.

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 <NUM> and <NUM>.

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 <CIT>.

The photoactive layer converts an electrical current into photons or photons into an electrical current.

The PAL may be formed on the HTL by vacuum deposition, spin coating, slot-die coating, printing, casting, LB deposition, or the like. When the PAL 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 PAL.

According to one embodiment of the present invention, the photoactive layer does not comprise the compound of formula (I).

The photoactive layer may be a light-emitting layer or a light-absorbing layer.

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, <NUM>,<NUM>'-N,N'-dicarbazole-biphenyl (CBP), poly(n-vinylcarbazole) (PVK), <NUM>,<NUM>-di(naphthalene-<NUM>-yl)anthracene (ADN), <NUM>,<NUM>',<NUM>"-tris(carbazol-<NUM>-yl)-triphenylamine(TCTA), <NUM>,<NUM>,<NUM>-tris(N-phenylbenzimidazole-<NUM>-yl)benzene (TPBI), <NUM>-tert-butyl-<NUM>,<NUM>-di-<NUM>-naphthylanthracenee (TBADN), distyrylarylene (DSA) and bis(<NUM>-(<NUM>-hydroxyphenyl)benzo-thiazolate)zinc (Zn(BTZ)<NUM>).

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)<NUM>, and Btp2lr(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)<NUM> (ppy = phenylpyridine), Ir(ppy)<NUM>(acac), Ir(mpyp)<NUM>.

Examples of phosphorescent blue emitter dopants are F2Irpic, (F2ppy)2Ir(tmd) and Ir(dfppz)<NUM> and ter-fluorene. <NUM>'-bis(<NUM>-diphenyl amiostyryl)biphenyl (DPAVBi), <NUM>,<NUM>,<NUM>,<NUM>-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 <NUM> to about <NUM> parts by weight, based on <NUM> 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 <NUM> to about <NUM>, for example, from about <NUM> to about <NUM>. When the thickness of the EML is within this range, the EML may have excellent light emission, without a substantial penalty in driving voltage.

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 <NUM> to about <NUM>, for example, from about <NUM> to about <NUM>. 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.

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 <NUM> to about <NUM>, for example, in the range from about <NUM> to about <NUM>. 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.

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 <NUM>-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 <NUM> to about <NUM>, for example, in the range from about <NUM> to about <NUM>. 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.

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 <NUM> to about <NUM>, for example, in the range from about <NUM> to about <NUM>. When the thickness of the cathode layer is in the range from about <NUM> to about <NUM>, 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.

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; an organic semiconductor 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 organic semiconductor 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 organic semiconductor 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.

The Organic semiconductor layer according to the invention may be the first hole injection layer and/or the p-type charge generation layer.

For example, the OLED according to <FIG> may be formed by a process, wherein on a substrate (<NUM>), an anode (<NUM>), a hole injection layer (<NUM>), a hole transport layer (<NUM>), an electron blocking layer (<NUM>), an emission layer (<NUM>), a hole blocking layer (<NUM>), an electron transport layer (<NUM>), an electron injection layer (<NUM>) and the cathode electrode (<NUM>) are subsequently formed in that order.

The organic electronic device according to the invention may be a light emitting device, or a photovoltaic cell, and preferably a light emitting device.

the method comprising the steps of forming the organic semiconductor layer; whereby for an organic light-emitting diode (OLED):.

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, the OLED may have the following layer structure, wherein the layers having the following order:
anode, organic semiconductor 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.

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 figures are illustrated in more detail with reference to examples. However, the present disclosure is not limited to the following figures.

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.

<FIG> is a schematic sectional view of an organic electronic device <NUM>, according to an exemplary embodiment of the present invention. The organic electronic device <NUM> includes a substrate <NUM>, an anode layer <NUM> and a hole injection layer (HIL) (<NUM>). The HIL <NUM> is disposed on the anode layer <NUM>. Onto the HIL <NUM>, a photoactive layer (PAL) <NUM> and a cathode layer <NUM> are disposed.

<FIG> is a schematic sectional view of an organic light-emitting diode (OLED) <NUM>, according to an exemplary embodiment of the present invention. The OLED <NUM> includes a substrate <NUM>, an anode layer <NUM> and a hole injection layer (HIL) <NUM>. The HIL <NUM> is disposed on the anode layer <NUM>. Onto the HIL <NUM>, a hole transport layer (HTL) <NUM>, an emission layer (EML) <NUM>, an electron transport layer (ETL) <NUM>, an electron injection layer (EIL) <NUM> and a cathode layer <NUM> are disposed. Instead of a single electron transport layer <NUM>, optionally an electron transport layer stack (ETL) can be used.

<FIG> is a schematic sectional view of an OLED <NUM>, according to another exemplary embodiment of the present invention. <FIG> differs from <FIG> in that the OLED <NUM> of <FIG> comprises an electron blocking layer (EBL) <NUM> and a hole blocking layer (HBL) <NUM>.

Referring to <FIG>, the OLED <NUM> includes a substrate <NUM>, an anode layer <NUM>, a hole injection layer (HIL) <NUM>, a hole transport layer (HTL) <NUM>, an electron blocking layer (EBL) <NUM>, an emission layer (EML) <NUM>, a hole blocking layer (HBL) <NUM>, an electron transport layer (ETL) <NUM>, an electron injection layer (EIL) <NUM> and a cathode layer <NUM>.

While not shown in <FIG> and <FIG>, a sealing layer may further be formed on the cathode layer <NUM>, in order to seal the organic electronic device <NUM>. In addition, various other modifications may be applied thereto.

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 <CIT> and <CIT>.

The HOMO and LUMO are calculated with the program package TURBOMOLE V6. <NUM> (TURBOMOLE GmbH, Litzenhardtstrasse <NUM>, <NUM> 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 <NUM>-<NUM>* basis set in the gas phase. If more than one conformation is viable, the conformation with the lowest total energy is selected.

The rate onset temperature (TRO) is determined by loading <NUM> compound into a VTE source. As VTE source a point source for organic materials may be used as supplied by Kurt J. Lesker Com-pany (www. com) or CreaPhys GmbH (http://www. The VTE source is heated at a constant rate of <NUM>/min at a pressure of less than <NUM>-<NUM> mbar and the temperature inside the source measured with a thermocouple. Evaporation of the compound is detected with a QCM detector which detects deposition of the compound on the quartz crystal of the detector. The deposition rate on the quartz crystal is measured in Ǻngstrom per second. To determine the rate onset temperature, the deposition rate is plotted against the VTE source temperature. The rate onset is the temperature at which noticeable deposition on the QCM detector occurs. For accurate results, the VTE source is heated and cooled three time and only results from the second and third run are used to determine the rate onset temperature.

To achieve good control over the evaporation rate of an organic compound, the rate onset temperature may be in the range of <NUM> to <NUM>. If the rate onset temperature is below <NUM> the evaporation may be too rapid and therefore difficult to control. If the rate onset temperature is above <NUM> the evaporation rate may be too low which may result in low tact time and decomposition of the organic compound in VTE source may occur due to prolonged exposure to elevated temperatures.

The rate onset temperature is an indirect measure of the volatility of a compound. The higher the rate onset temperature the lower is the volatility of a compound.

According to one embodiment, the rate onset temperature of compound of formula (I) is selected in the range of ≥ <NUM> and ≤ <NUM>; preferably of ≥ <NUM> and ≤ <NUM>.

For bottom emission devices, see Table <NUM>, a 15Ω /cm<NUM> glass substrate with <NUM> ITO (available from Corning Co. ) was cut to a size of <NUM> x <NUM> x <NUM>, ultrasonically washed with isopropyl alcohol for <NUM> minutes and then with pure water for <NUM> minutes, and washed again with UV ozone for <NUM> minutes, to prepare the anode.

Then, Biphenyl-<NUM>-yl(<NUM>,<NUM>-diphenyl-<NUM>-fluoren-<NUM>-yl)-[<NUM>-(<NUM>-phenyl-<NUM>-carbazol-<NUM>-yl)phenyl]-amine (<NPL>) and compound of formula (I) according to Table <NUM> were vacuum deposited on the anode, to form a HIL having a thickness of <NUM>. The amount of compound of formula (I) in the HIL can be seen in Table <NUM>.

Then, Biphenyl-<NUM>-yl(<NUM>,<NUM>-diphenyl-<NUM>-fluoren-<NUM>-yl)-[<NUM>-(<NUM>-phenyl-<NUM>-carbazol-<NUM>-yl) phenyl]-amine was vacuum deposited on the HIL, to form a first HTL having a thickness of <NUM>.

Then N,N-bis(<NUM>-(dibenzo[b,d]furan-<NUM>-yl)phenyl)-[<NUM>,<NUM>':<NUM>',<NUM>"-terphenyl]-<NUM>-amine (<NPL>) was vacuum deposited on the HTL, to form an electron blocking layer (EBL) having a thickness of <NUM>.

Then <NUM> vol. -% H09 (Sun Fine Chemicals, Korea) as EML host and <NUM> vol. -% BD200 (Sun Fine Chemicals, Korea) as fluorescent blue dopant were deposited on the EBL, to form a first blue-emitting EML with a thickness of <NUM>.

Then the hole blocking layer is formed with a thickness of <NUM> by depositing <NUM>-(<NUM>'-(<NUM>,<NUM>-dimethyl-<NUM>-fluoren-<NUM>-yl)-[<NUM>,<NUM>'-biphenyl]-<NUM>-yl)-<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazine on the emission layer.

Then, the electron transporting layer (ETL) having a thickness of <NUM> is formed on the hole blocking layer by depositing <NUM> wt. -% <NUM>'-(<NUM>-(<NUM>-(<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl)phenyl)naphthalen-<NUM>-yl)-[<NUM>,<NUM>'-biphenyl]-<NUM>-carbonitrile and <NUM> wt.

Al is evaporated at a rate of <NUM> to <NUM>Å/s at <NUM>-<NUM> mbar to form a cathode with a thickness of <NUM>.

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 <NUM>. The current-voltage characteristic is determined using a Keithley <NUM> source measure unit, by sourcing a voltage 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 <NUM>. 1V in the range between 0V and 10V. Likewise, the luminance-voltage characteristics and CIE coordinates are determined by measuring the luminance in cd/m<NUM> using an Instrument Systems CAS-140CT array spectrometer (calibrated by Deutsche Akkreditierungsstelle (DAkkS)) for each of the voltage values. The cd/A efficiency at <NUM> mA/cm2 is determined by interpolating the luminance-voltage and current-voltage characteristics, respectively.

In bottom emission devices, the emission is predominately Lambertian and quantified in percent external quantum efficiency (EQE). To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at <NUM> mA/cm2.

In top emission devices, the emission is forward directed, non-Lambertian and also highly dependent on the mirco-cavity. Therefore, the efficiency EQE will be higher compared to bottom emission devices. To determine the efficiency EQE in % the light output of the device is measured using a calibrated photodiode at <NUM> mA/cm<NUM>.

Lifetime LT of the device is measured at ambient conditions (<NUM>) and <NUM> mA/cm<NUM>, using a Keithley <NUM> sourcemeter, and recorded in hours.

The brightness of the device is measured using a calibrated photo diode. The lifetime LT is defined as the time till the brightness of the device is reduced to <NUM> % of its initial value.

In Table <NUM> are shown LUMO levels and rate onset temperatures TRO (when available) for Examples <NUM> to <NUM> (=E1 to E11) and comparative example <NUM> and <NUM> (=C1 and C2). Example <NUM> (=E8) is not forming part of the claimed invention.

In all examples and comparative examples, the compounds were essentially isomer free and resembled the structure of formula (IV) as described above.

LUMO levels were calculated with the program package TURBOMOLE V6. <NUM> (TURBOMOLE GmbH, Litzenhardtstrasse <NUM>, <NUM> Karlsruhe, Germany) by applying the hybrid functional B3LYP with a <NUM>-<NUM>* basis set in the gas phase.

In comparative example <NUM>, the calculated LUMO level is -<NUM> eV. R<NUM> and R<NUM> are selected from OCF<NUM>. A<NUM> is selected from formula (IIIa), wherein R<NUM> and R<NUM> are selected from OCF<NUM>. Ar in A<NUM> is selected from <NUM>,<NUM>-bis(trifluoromethoxy)phenyl.

In comparative example <NUM>, the calculated LUMO level is -<NUM> eV. R<NUM> and R<NUM> are selected from F. A<NUM> and A<NUM> are selected from formula (IIIa), wherein R<NUM> and R<NUM> are selected from F.

In Example <NUM>, the LUMO level is shown. Example <NUM> differs from comparative example <NUM> in the selection of R<NUM> and R<NUM> in formula (II) and formula (IIIa). In the example, R<NUM> and R<NUM> in formula (II) and formula (IIIa) are selected from CF<NUM>. The LUMO level is improved to -<NUM> eV. Without being bound by theory, a LUMO level further away from vacuum level may improve doping strength of matrix compounds.

In Example <NUM>, the LUMO level and TRO are is shown. Example <NUM> differs from Example <NUM> in the selection of A<NUM> and A<NUM>. A<NUM> and A<NUM> comprise phenyl groups substituted with four F atoms and one CF<NUM> group. The LUMO level is improved over comparative examples <NUM> and <NUM>. Additionally, the rate onset temperature is in a range which is suitable for mass production of organic electronic devices.

In Examples <NUM> to <NUM>, the LUMO level is improved over comparative examples <NUM> and <NUM>, see Table <NUM>.

In summary, improved LUMO levels have been obtained. Additionally, the rate onset temperature is in a range suitable for mass production of organic electronic devices.

In Table <NUM> are shown operating voltage, cd/A efficiency, EQE and LT97 of organic electronic devices comprising an organic semiconductor layer comprising compound of formula (I).

In device No. <NUM>, the organic semiconductor layer comprises <NUM> vol. -% Example <NUM>. The operating voltage is <NUM> V, the cd/A efficiency is <NUM> cd/A, the external quantum efficiency EQE is <NUM> % and the LT97 is <NUM> hours.

In device No. <NUM>, the organic semiconductor layer comprises <NUM> vol. -% Example <NUM>. The operating voltage is reduced to <NUM> V, the cd/A efficiency is <NUM> cd/A, the external quantum efficiency EQE is <NUM> % and the LT97 is <NUM> hours.

In device No. <NUM>, the organic semiconductor layer comprises <NUM> vol. -% Example <NUM>. The operating voltage is further reduced to <NUM> V, the cd/A efficiency is improved to <NUM> cd/A, the external quantum efficiency EQE is improved to <NUM> % and the LT97 is <NUM> hours.

In device No. <NUM>, the organic semiconductor layer comprises <NUM> vol. -% Example <NUM>. The operating voltage is <NUM> V, the cd/A efficiency is improved to <NUM> cd/A, the external quantum efficiency EQE is further improved to <NUM> % and the LT97 is <NUM> hours.

A low operating voltage may be beneficial for reduced power consumption and improved battery life, in particular in mobile devices.

A high cd/A efficiency and/or EQE may be beneficial for reduced power consumption and improved battery life, in particular in mobile devices.

An improved LT97 may be beneficial for long lifetime of organic electronic devices.

The particular combinations of elements and features in the above detailed embodiments are exemplary only.

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 scope of the invention as claimed. Accordingly, the foregoing description is by way of example only and is not intended as limiting. 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.

Claim 1:
An organic electronic device (<NUM>) comprising an anode layer (<NUM>), a cathode layer (<NUM>) and at least one organic semiconductor layer, wherein the at least one organic semiconductor layer is arranged between the anode layer (<NUM>) and the cathode layer (<NUM>); and characterized in that
the at least one organic semiconductor layer comprises a compound of formula (I)
<CHM>
whereby A<NUM> is selected from formula (II)
<CHM>
whereby
R<NUM> is selected from partially or perfluorinated C<NUM> to C<NUM> alkyl or CN,
R<NUM> is selected partially or perfluorinated C<NUM> to C<NUM> alkyl,
X<NUM> is selected from CH or N;
X<NUM> and X<NUM> are independently selected from CH, CF or N;
wherein at least one of X<NUM>, X<NUM> and X<NUM> is selected from CH;
and A<NUM> is linked to the cyclopropene core via the atom marked as "*";
R<NUM> is selected from CN,
and
A<NUM> and A<NUM> are independently selected from formula (III),
<CHM>
wherein Ar is independently selected from substituted or unsubstituted C<NUM> to C<NUM> aryl and substituted or unsubstituted C<NUM> to C<NUM> heteroaryl, wherein the substituents on Ar are independently selected from CN, partially or perfluorinated C<NUM> to C<NUM> alkyl, halogen, F.