Organic light emitting diode and device including same

Abstract

The invention relates to an organic light emitting diode. The present invention relates to an organic light emitting diode, and to a display device or a lighting device comprising the same, the organic light emitting diode comprising an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generation layer, and a first electron transport layer stacked layer.

Description

Technical Field

[0001] The invention relates to an organic light emitting diode and a device comprising the same. Background Art

[0002] As a self-luminous device, an organic light-emitting diode (OLED) has a wide viewing angle, excellent contrast, fast response, high brightness, excellent driving voltage characteristics and color reproducibility. A typical OLED comprises an anode, a hole transport layer (HTL), an emitting layer (EML), an electron transport layer (ETL) and a cathode stacked sequentially on a substrate. In this regard, HTL, EML and ETL are thin films formed by organic and / or organometallic compounds.

[0003] When voltage is applied to the anode and cathode, holes injected from the anode electrode move to the EML through the HTL, and electrons injected from the cathode electrode move to the EML through the ETL. Holes and electrons recombine in the EML to generate excitons. When the excitons drop from the excited state to the ground state, light is emitted. The injection and flow of holes and electrons should be balanced so that the OLED having the above structure has excellent efficiency.

[0004] Various organic light emitting diodes comprising different electron transport materials are well known in the art. However, there is still a need to improve the performance of such devices, in particular to improve the performance of multi-emitting layer OLEDs, in particular with regard to lifetime and efficiency (C Eff ), especially life span.

[0005] Therefore, an object of the present invention is to provide an organic light emitting diode that can overcome the disadvantages of the prior art, in particular a multi-emitting layer top-emitting OLED with improved performance, which has improved lifespan and efficiency (C Eff ), especially life span. Summary of the invention

[0006] The object is achieved by an organic light emitting diode comprising a stack of an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generation layer and a first electron transport layer; wherein

[0007] - the first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer;

[0008] - the first electron transport layer stack is arranged between the first light-emitting layer and the second light-emitting layer;

[0009] - the first electron transport layer stack comprises a first electron transport layer and a second electron transport layer;

[0010] - The first electron transport layer comprises a compound of formula (I)

[0011] (Ar1 -A c ) a -X b (I);

[0012] -a and b are independently 1 or 2;

[0013] -c is independently 0 or 1;

[0014] -Ar 1 Independently selected from C6 to C 60 Aryl or C2 to C 42 Heteroaryl,

[0015] - Each Ar 1 may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0016] -Ar 1 Each C6 to C 12 Aryl substituents and Ar 1 Each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen;

[0017] -A is independently selected from C6 to C 30 Aryl,

[0018] - wherein each A may be substituted by one or two substituents independently selected from the following: C6 to C 12Aryl and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0019] - Each C6 to C on A 12 The aryl substituents may be substituted with C1 to C4 alkyl or halogen;

[0020] -X is independently selected from C2 to C 42 Heteroaryl and C6 to C 60 Aryl,

[0021] - wherein each X may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0022] - where each C6 to C on X 12 The aryl substituent and each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen;

[0023] - the molecular dipole moment of the compound of formula (I) is ≥0D and ≤4D;

[0024] The second electron transport layer comprises a compound of formula (II)

[0025] (Ar 2 ) m -(Z k -G) n (II);

[0026] - m and n are independently 1 or 2;

[0027] - k is independently 0, 1 or 2;

[0028] -Ar 2 Independently selected from C2 to C 42 Heteroaryl and C6 to C 60 Aryl,

[0029] - Each Ar 2 may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0030] -Ar 2 Each C6 to C 12 Aryl substituents and Ar 2 Each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen;

[0031] -Z is independently selected from C6 to C 30 Aryl,

[0032] - wherein each Z may be substituted by one or two substituents independently selected from the following: C6 to C 12Aryl and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0033] - where each C6 to C on Z 12 The aryl substituents may be substituted with C1 to C4 alkyl or halogen;

[0034] - G is selected so that the dipole moment of the compound G-phenyl is ≥ 1D and ≤ 7D;

[0035] - the first electron transport layer and the second electron transport layer do not contain electrical dopants;

[0036] - the first charge generation layer comprises the compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer; and

[0037] -G contains the portion P=O.

[0038] The object is also achieved by a device comprising the organic light emitting diode of the present invention, wherein the device is a display device or a lighting device.

[0039] In the display device or the lighting device, light may be emitted through the transparent cathode.

[0040] In the display device or the lighting device, light may be emitted through the transparent anode.

[0041] First electron transport layer

[0042] The first electron transport layer comprises a compound of formula (I)

[0043] (Ar 1 -A c ) a -X b (I).

[0044] The first electron transport layer may be composed of a compound of formula (I). Alternatively, the first electron transport layer may be composed of a mixture of a compound of formula (I) and one or more other compounds, provided that none of the other compounds is an electrical dopant. The first electron transport layer may contain more than one compound of formula (I). In particular, the first electron transport layer may be composed of a mixture of a compound of formula (I) and other compounds known in the art as electron transport host compounds. Exemplary other electron transport host compounds that may be included are disclosed below.

[0045] In the compounds of formula (I), the group "A" is the linker (if present, i.e. in the case of c>1) to the group Ar 1 and the spacer moiety of X. In the case where the compound of formula (I) contains more than one group (Ar 1 -A c ), the group may or may not independently contain a spacer group A.

[0046] In the compounds of formula (I), a and b are independently 1 or 2. Alternatively, a and b may both be 1.

[0047] In the compounds of formula (I), c is independently 0 or 1.

[0048] Ar 1 Independently selected from C6 to C 60 Aryl or C2 to C 42 Heteroaryl, or C6 to C 54 Aryl or C2 to C 39 Heteroaryl, or C6 to C 48 Aryl or C2 to C 36 Heteroaryl, or C6 to C 42 Aryl or C2 to C 36 Heteroaryl, or C6 to C 36 Aryl or C2 to C 30 Heteroaryl, or C6 to C 30 Aryl or C2 to C 24 Heteroaryl.

[0049] Ar 1 Can be independently C6 to C 54 Aryl, optionally C6 to C 48 Aryl, optionally C6 to C 42 Aryl, optionally C6 to C 36 Aryl, optionally C6 to C 30 Aryl and optionally C6 to C 24 Aryl.

[0050] Ar 1 Can be independently C2 to C 42 Heteroaryl, optionally C2 to C40 Heteroaryl, optionally C2 to C 36 Heteroaryl, optionally C2 to C 30 heteroaryl and optionally C2 to C 24 Heteroaryl.

[0051] In one embodiment, Ar 1 Different from X.

[0052] Ar 1 The system may contain two or more fused aromatic rings, preferably three or more fused aromatic rings.

[0053] Ar 1 Can contain at least one sp 3 -Hybridized carbon atoms.

[0054] Ar 1 may contain at least one carbon-carbon sp not incorporated into the aromatic ring structure 2 Olefin bond.

[0055] In one embodiment, wherein Ar 1 independently selected from unsubstituted C2 to C 42 Heteroaryl, the heteroatom is bonded to Ar by a single bond 1 in the molecular structure.

[0056] Ar 1 may be independently selected from phenyl, naphthyl, anthracenyl, fluoranthenyl, xanthene, dibenzofuranyl, pyrimidinyl, pyrazinyl, spiro-xanthene, fluorenyl, spiro-fluorenyl, triphenylsilyl, tetraphenylsilyl or a group having formula (IIa) or (IIb),

[0057]

[0058] in

[0059] - the asterisk symbol "*" indicates the binding position of the group of formula (IIa) to A; and

[0060] -R 1 To R 9 Independently selected from H, C6 to C 12 Aryl and C4 to C 10 Heteroaryl.

[0061] In the group of formula (IIa), R 6 and R 7 Both; and / or R 8 and R 9 Both may be phenyl groups.

[0062] If Ar 1is a group of formula (IIb), then the bonding of the group of formula (IIb) to A (or to X if A is absent in the case of c=0) can be via the group R 6 To R 9 wherein (formally) A (in some cases X) replaces the corresponding R 6 To R 9 The terminal hydrogen atom.

[0063] Ar 1 may be independently selected from: fluoranthene group, dibenzofuranyl group, pyrimidinyl group, pyrazinyl group, 9,9-dimethylfluorenyl group, a group having formula (IIa), a group having formula (IIb),

[0064]

[0065] in

[0066] - the asterisk symbol "*" indicates the binding position of the group of formula (IIa) to A; and

[0067] -R 1 is H, and R 2 To R 5 are independently phenyl; or

[0068] -R 1 and R 3 is phenyl, and R 2 , R 4 and R 5 is H; or

[0069] -R 6 To R 9 It is phenyl.

[0070] If Ar 1 is a group of formula (IIb), then the bonding of the group of formula (IIb) to A (or to X if A is absent in the case of c=0) can be via the group R 6 To R 9 In which (formally) A (in some cases X) replaces the corresponding R 6 To R 9 The terminal hydrogen atom.

[0071] In the group of formula (IIa), R 1 To R 5 At least two of the Rs other than H may be in adjacent positions to each other. 1 To R 5In this regard, if two groups are respectively bonded to adjacent carbon atoms of the benzene ring in formula (IIa), the two groups are in ortho position to each other. In other words, it can be stipulated that R 1 and R 5 At least one of them is phenyl; and / or R 1 and R 2 are phenyl; and / or R 2 and R 3 are phenyl; and / or R 3 and R 4 are phenyl; and / or R 4 and R 5 All are phenyl.

[0072] Ar 1 Can be independently selected from one of the following groups,

[0073]

[0074] The asterisk symbol "*" indicates the binding position for binding to A, and Ar 1 may be substituted or unsubstituted, respectively.

[0075] In Ar 1 Where substituted, each substituent may be independently selected from the group consisting of phenyl, naphthyl, biphenyl, pyridyl, methylpyridyl, dimethylpyridyl, dibenzofuranyl, dibenzothienyl and benzothienyl.

[0076] A may be independently selected from the group consisting of a phenylene group, a naphthalene group, a biphenylene group and a terphenylene group, and the groups may be substituted or unsubstituted, respectively.

[0077] A can be independently selected from one or a combination of the following groups,

[0078]

[0079] For binding to Ar 1 The binding position of and X can be freely selected, preferably,

[0080]

[0081] In the case where A is substituted, each substituent on A may be independently selected from phenyl and C1 to C4 alkyl.

[0082] X can be independently selected from C2 to C 39 Heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30Heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Heteroaryl and C6 to C 30 Aryl, and optionally C3 to C 21 Heteroaryl and C6 to C 24 Aryl, wherein the corresponding radical may be substituted or unsubstituted.

[0083] X can be independently selected from C2 to C 39 Containing N heteroaryl, C2 to C 39 O-containing heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Containing N heteroaryl, C2 to C 36 O-containing heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30 Containing N heteroaryl, C3 to C 30 O-containing heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Containing N heteroaryl, C3 to C 27 O-containing heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Containing N heteroaryl, C3 to C 24 O-containing heteroaryl and C6 to C 30 Aryl, and optionally C3 to C 21 Containing N heteroaryl, C3 to C 21 O-containing heteroaryl and C6 to C 24 Aryl.

[0084] X can be independently selected from C2 to C 39 Containing N heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Containing N heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30 Containing N heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Containing N heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Containing N heteroaryl and C6 to C 30 Aryl, and optionally C3 to C 21 Containing N heteroaryl and C6 to C 24 Aryl. In this connection, it can be provided that the corresponding N-containing heteroaryl group contains one or more N atoms as the only heteroatom(s).

[0085] X may be independently selected from the following groups: triazine group, 1,2-diazine group, 1,3-diazine group, 1,4-diazine group, quinazolinyl group, benzoquinazolinyl group, benzimidazolyl group, quinolinyl group, benzoquinolinyl group, benzoacridinyl group, dibenzoacridinyl group, fluoranthenyl group, anthracenyl group, naphthyl group, terphenylidene group, phenanthroline group and dinaphthofuranyl group, and the groups may be substituted or unsubstituted, respectively.

[0086] X may be independently selected from the following groups: triazine group, 1,2-diazine group, 1,3-diazine group, 1,4-diazine group, quinazolinyl group, benzoquinazolinyl group, benzoacridinyl group, dibenzoacridinyl group, fluoranthenyl group, anthracenyl group, naphthyl group, terphenylidene group, phenanthroline group and dinaphthofuranyl group, and the groups may be substituted or unsubstituted, respectively.

[0087] X may be independently selected from the following groups: triazine group, 1,2-diazine group, 1,3-diazine group, 1,4-diazine group, quinazolinyl group, benzoquinazolinyl group, benzoacridinyl group, dibenzoacridinyl group, fluoranthenyl group, and the groups may be substituted or unsubstituted.

[0088] X can be independently selected from one of the following groups:

[0089]

[0090] The asterisk symbol "*" represents the binding position of the group to A.

[0091] In the case where X is substituted, each substituent on X may be independently selected from phenyl, naphthyl, and biphenyl. In the case where X is substituted, each substituent on X may be independently selected from phenyl and biphenyl.

[0092] In the case where X is substituted, the corresponding substituted X group may be,

[0093]

[0094] The asterisk symbol "*" indicates the binding position of the group to A. X (including substituents) can be independently selected from one of the following groups,

[0095]

[0096] The asterisk "*" indicates the binding position with A, and in the case of c = 0, it corresponds to Ar 1 Combine.

[0097] It may be provided that the compound of formula (I) does not contain a P=O moiety. It may be provided that the compound of formula (I) does not contain a P(=O)aryl2. It may be provided that the compound of formula (I) does not contain a P(=O)alkyl2. It may be provided that the compound of formula (I) does not contain a P(=O)Ph2. It may be provided that the compound of formula (I) does not contain a P(=O)(CH3)2. It may be provided that the compound of formula (I) does not contain R'P(=O)R", wherein R' and R" are linked to each other to form a ring, i.e., does not contain a cyclo-phosphine oxide. It may be provided that the compound of formula (I) does not contain R'P(=O)R", wherein R' and R" are linked to each other to form a 7-membered ring.

[0098] It may be provided that the compound of formula (I) does not contain two P=O moieties. It may be provided that the compound of formula (I) does not contain two P(=O)aryl2. It may be provided that the compound of formula (I) does not contain two P(=O)alkyl2. It may be provided that the compound of formula (I) does not contain two P(=O)Ph2. It may be provided that the compound of formula (I) does not contain two P(=O)(CH3)2. It may be provided that the compound of formula (I) does not contain CN.

[0099] It may be provided that one or more of the following formulae are not included within the scope of compounds of formula (I):

[0100]

[0101]

[0102] The compounds of formula (I) may contain 6 to 14 aromatic or heteroaromatic rings, optionally 7 to 13 aromatic or heteroaromatic rings, optionally 7 to 12 aromatic or heteroaromatic rings, optionally 9 to 11 aromatic or heteroaromatic rings. In this respect, an aromatic ring, respectively a heteroaromatic ring, is a single aromatic ring, for example: a 6-membered aromatic ring such as phenyl; a 6-membered heteroaromatic ring, an example would be pyridyl; a 5-membered heteroaromatic ring, an example would be pyrrolyl, etc. In a system of fused (hetero)aromatic rings, each ring is considered in this respect to be a single ring. For example, naphthalene contains two aromatic rings.

[0103] The molecular dipole moment of the compound of formula (I) can be calculated by TURBOMOLE V6.5 package using hybrid functional B3LYP and Gaussian6-31G* basis set, and can be ≥0D and ≤4D; or ≥0D and ≤3.5D; or ≥0D and ≤3.0D; or ≥0D and ≤2.5D; or ≥0D and ≤2.0D. In this regard, the dipole moment of a molecule containing N atoms is Given by:

[0104]

[0105] where q i and is the partial charge and position of atom i in the molecule. The dipole moment is determined by the semi-empirical molecular orbital method. Use the hybrid functional B3LYP and 6-31G* basis set in the gas phase to optimize the geometry of the molecular structure as implemented in the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany). If more than one conformation is feasible, the conformation with the lowest total energy is selected to determine the bond length of the molecule.

[0106] In one embodiment, the LUMO energy level of the compound of formula (I) is calculated by the TURBOMOLE V6.5 program package using the hybrid functional B3LYP and the Gaussian6-31G* basis set, taking the vacuum energy level as zero absolute scale, and is in the range of -1.90 eV to -1.60 eV, preferably -1.87 eV to -1.65 eV, preferably -1.85 eV to -1.65 eV.

[0107] The compound of formula (I) may be selected from compounds A-1 to A-41 in Table 1 below.

[0108] Table 1:

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] In one embodiment, the LUMO energy level of the compound of formula (I) is calculated by the TURBOMOLE V6.5 package using the hybrid functional B3LYP and the Gaussian6-31G* basis set, with the vacuum level as zero absolute scale, and is in the range of -1.90 eV to -1.45 eV, preferably -1.89 eV to -1.47 eV.

[0118] The first electron transport layer may be arranged between the light emitting layer and the second electron transport layer. The first electron transport layer may be arranged to be in direct contact with the light emitting layer. The first electron transport layer may be arranged as a "contact sandwich" between the light emitting layer and the second electron transport layer.

[0119] The first electron transport layer may have a thickness of <50 nm, optionally between 1 nm and 30 nm, optionally between 1 nm and 10 nm, optionally between 1 nm and 5 nm.

[0120] Second electron transport layer

[0121] The second electron transport layer comprises a compound of formula (II)

[0122] (Ar 2 ) m -(Z k -G) n (II).

[0123] The second electron transport layer may be composed of a compound of formula (II). Alternatively, the second electron transport layer may be composed of a mixture of a compound of formula (II) and one or more other compounds, provided that none of the other compounds is an electrical dopant. The second electron transport layer may contain more than one compound of formula (II). The second electron transport layer may be composed of a mixture of a compound of formula (II) and other compounds known in the art as electron transport host compounds. Exemplary other electron transport host compounds that may be included are disclosed below.

[0124] G comprises a P=O moiety. The term "comprising a P=O moiety" refers in particular to phosphine oxides and generally to all compounds in which the P=O group is bound to three other groups via a single bond to the P atom, for example, a phosphinyl group (P(=O)R2) which may be bound to Z via a single bond or via any organic divalent group.

[0125] In the compounds of formula (II), the group "Z" is a linker (if present, ie in the case of k>1) to the group Ar 2 and the spacer portion of G. In the case where the compound of formula (II) contains more than one group (Z k In the case of -G), the group may or may not independently contain a spacer group Z.

[0126] In formula (II), m and n are independently 1 or 2. In formula (II), m and n may be 1.

[0127] In formula (II), k is independently 0, 1 or 2. In formula (II), k may be independently 1 or 2.

[0128] Ar 2 Can be independently selected from C2 to C39 Heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30 Heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Heteroaryl and C6 to C 30 Aryl, and optionally C3 to C 21 Heteroaryl and C6 to C 24 Aryl.

[0129] Ar 2 Can be independently selected from C2 to C 39 Containing N heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Containing N heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30 Containing N heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Containing N heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Containing N heteroaryl and C6 to C 30 Aryl, and optionally C3 to C 21 Containing N heteroaryl and C6 to C 24 Aryl. In this connection, it can be provided that the corresponding N-containing heteroaryl group contains one or more N atoms as the only heteroatom(s).

[0130] Ar 2 At least two fused 5-membered rings or 6-membered rings may be contained.

[0131] Ar 2 The benzophenone group may be independently selected from the group consisting of a pyridyl group, a triazine group, a 1,2-diazine group, a 1,3-diazine group, a 1,4-diazine group, a quinazolinyl group, a benzoquinazolinyl group, a benzimidazolyl group, a quinolinyl group, a benzoquinolinyl group, a benzoacridinyl group, a dibenzoacridinyl group, a fluoranthenyl group, an anthracenyl group, a naphthyl group, a terphenylidene group, a phenanthroline group and a dinaphthofuranyl group, and the groups may be substituted or unsubstituted, respectively.

[0132] Ar 2 The benzoquinazolinyl group may be independently selected from the group consisting of a 1,3-diazinyl group, a 1,4-diazinyl group, an anthracenyl group, a triazinyl group and a benzoquinazolinyl group.

[0133] Ar 2 Can be independently selected from one of the following groups,

[0134]

[0135] The asterisk symbol "*" indicates the binding position for binding to Z.

[0136] In Ar 2 When substituted, Ar 2 Each substituent on may be independently selected from phenyl, naphthyl, optional β-naphthyl, pyridyl and biphenyl, which groups may be substituted or unsubstituted, respectively.

[0137] In Ar 2 When substituted, Ar 2 Each substituent on may be independently selected from phenyl, pyridyl and biphenyl, optionally p-biphenyl.

[0138] Ar 2 (including all substituents) can be selected from

[0139]

[0140]

[0141] The asterisk symbol "*" indicates the binding position for binding to Z.

[0142] Z can be independently selected from C6 to C 30 Aryl, or C6 to C 24 Aryl, or C6 to C 18 Aryl, or C6 to C 12 Aryl, said groups may be substituted or unsubstituted, respectively.

[0143] Z may be selected from a benzene group, a naphthalene group, a benzene-naphthalene group, a benzene-naphthalene group-benzene group, a benzene-anthracene group-benzene group, a biphenyl group and a terphenyl group, and the groups may be substituted or unsubstituted, respectively.

[0144] Z can be independently selected from one of the following groups,

[0145]

[0146] Among them, Ar 2 The binding position with G can be freely selected.

[0147] In the case where Z is substituted, each substituent on Z may be independently selected from phenyl and C1 to C4 alkyl.

[0148] G is selected so that the dipole moment of the compound G-phenyl calculated by the TURBOMOLE V6.5 program package using the hybrid functional B3LYP and Gaussian 6-31G* basis set is ≥1D and ≤7D. The unit of dipole moment "Debye (Debye)" is abbreviated as the symbol "D". The inventors have found that if the compound of formula (II) contains a group with a specific polarity, i.e., a group with a specific dipole moment within the above range or the following range, it is advantageous. It is also found that if the compound of formula (II) additionally contains another polar group (second polar group), it is still advantageous for the compound of formula (II) to contain this type of polar group (first polar group), and the other polar group (second polar group) is suitable for balancing the dipole moment of the first polar group, so that the total dipole moment of the compound of formula (II) is low. For example, when the compound is a symmetrical molecule containing the same first polar group and the second polar group, the dipole moment can be 0 Debye. Therefore, the compound of formula (II) cannot be characterized by reference to the total dipole moment of the compound. Therefore, reference is made instead to a simulated compound containing a polar group "G" and a nonpolar group "phenyl". In this regard, the dipole moment of a compound containing N atoms Given by:

[0149]

[0150] where q i and It is the partial charge and position of atom i in the molecule. Dipole moment is determined by semi-empirical molecular orbital method. As implemented in program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135Karlsruhe, Germany), hybrid functional B3LYP and 6-31G* basis set are used to optimize the geometry of molecular structure in gas phase. If more than one conformation is feasible, the conformation with the lowest total energy is selected to determine the bond length of the molecule. In this respect, the whole G part includes all possible substituents that can be included.

[0151] G may be selected such that the dipole moment of compound G-phenyl is: >1D, optionally ≥2D, optionally ≥2.5D, optionally ≥2.5D, optionally ≥3D, and optionally ≥3.2D. G may be selected such that the dipole moment of compound G-phenyl is ≤7D, optionally ≤6.7D.

[0152] In one embodiment, the dipole moment of compound G-phenyl is ≥3D and ≤6D; optionally ≥3.2D and ≤6.7D.

[0153] If more than one conformer of the compound G-phenyl is possible, the average value of the dipole moments of the conformers of G-phenyl is selected to be within this range.Conformer isomerism is a form of stereoisomerism in which isomers are convertible into one another solely by rotation about formally single bonds.

[0154] By selecting G so that the dipole moment of compound G-phenyl is within the above range, electron injection from an adjacent different charge generation layer (CGL) can be improved, and the voltage of the OLED device can be reduced, and the cd / A efficiency of the OLED device can be increased.

[0155] The exemplary compound "G-phenyl" is listed below in Table 2, wherein the moieties in the corresponding compounds are

[0156]

[0157] Indicated as "G- Phenyl "The "phenyl" part of ":

[0158]

[0159]

[0160]

[0161]

[0162] Table 2:

[0163]

[0164]

[0165]

[0166]

[0167] G can be selected from the group consisting of: dialkylphosphinyl, diarylphosphinyl, diheteroarylphosphinyl, alkylarylphosphinyl, alkylheteroarylphosphinyl, arylheteroarylphosphinyl, aryl groups substituted by dialkylphosphinyl, aryl groups substituted by diarylphosphinyl, aryl groups substituted by diheteroarylphosphinyl, aryl groups substituted by alkylarylphosphinyl, aryl groups substituted by alkylheteroarylphosphinyl and aryl groups substituted by arylheteroarylphosphinyl. The two groups (alkyl groups, aryl groups, heteroaryl groups) in the phosphinyl group can be connected to each other, especially connected to each other via a single bond, thereby forming a ring, especially a 5-membered ring, wherein the P atom of P=O is part of the ring. For example, if G is a diarylphosphinyl group, the two aryl groups can be connected to each other, especially connected to each other via a single bond, thereby forming a ring, especially a 5-membered ring, wherein the P atom of P=O is part of the ring. The same applies to all other combinations of alkyl, aryl and heteroaryl, such as dialkyl, alkylaryl, arylheteroaryl and the like.

[0168] G can be selected from: di-C1 to C4 alkylphosphinyl, di-C6 to C 10 Arylphosphinyl, C 10 Bis(heteroaryl)phosphinyl, C7-C 25 Arylheteroarylphosphinyl, C8-C 42 Phosphine oxide, containing C8-C 42 Phosphine oxides containing C8-C 24 Heteroaryl phosphine oxide, C 12 -C 42 Cyclic aryl phosphinyl, C7-C 25 Cyclic arylheteroarylphosphinyl and C7-C 25 wherein the corresponding G may contain one or more substituents connected to the group, wherein the one or more substituents are selected from C6 to C 10 Aryl, C1 to C4 alkyl, C2 to C5 heteroaryl.

[0169] G may be independently selected from dimethylphosphinyl, diphenylphosphinyl,

[0170]

[0171]

[0172]

[0173]

[0174] Wherein, if an asterisk symbol "*" is present, it indicates the binding position. If the formula does not have an asterisk symbol "*", the binding position can be freely selected.

[0175] G may be independently selected from dimethylphosphinyl, diphenylphosphinyl,

[0176]

[0177]

[0178]

[0179]

[0180]

[0181] The asterisk symbol "*" indicates the binding position.

[0182] G may be selected from dialkylphosphinyl and diarylphosphinyl, and may be selected from C1 to C6 dialkylphosphinyl, especially C1 to C4 dialkylphosphinyl, and C6 to C 10 The diarylphosphinyl group may be selected, for example, from dimethylphosphinyl (P(=O)(CH3)2) and diphenylphosphinyl (P(=O)(C6H5)2).

[0183] The compounds of formula (II) may contain 6 to 12 aromatic or heteroaromatic rings, optionally 6 to 11 aromatic or heteroaromatic rings, optionally 7 to 10 aromatic or heteroaromatic rings, optionally 7 to 9 aromatic or heteroaromatic rings. In this respect, an aromatic ring, respectively a heteroaromatic ring, is a single aromatic ring, for example: a 6-membered aromatic ring such as phenyl; a 6-membered heteroaromatic ring, an example would be pyridyl; a 5-membered heteroaromatic ring, an example would be pyrrolyl, etc. In a system of fused (hetero)aromatic rings, each ring is considered in this respect to be a single ring. For example, naphthalene contains two aromatic rings.

[0184] The compound of formula (II) may be selected from B-1 to B-45 and / or the compounds shown in Table 3.

[0185]

[0186]

[0187]

[0188]

[0189]

[0190] Exemplary compounds of formula (II) and their properties are summarized in Table 3.

[0191] Table 3:

[0192]

[0193]

[0194]

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201]

[0202] In one embodiment, the LUMO energy level of the compound of formula (II) is calculated by the TURBOMOLE V6.5 program package using the hybrid functional B3LYP and the Gaussian6-31G* basis set, with the vacuum energy level as zero absolute scale, and is in the range of -2.30 eV to -1.20 eV, preferably -2.00 eV to -1.60 eV, preferably -1.97 eV to -1.65 eV.

[0203] In one embodiment, the compound of formula (II) comprises one polar group "G".

[0204] The second electron transport layer may also include compound (III), wherein compound (III) includes 8 to 13 aromatic or heteroaromatic rings, optionally 8 to 11 aromatic or heteroaromatic rings, optionally 9 to 11 aromatic or heteroaromatic rings and optionally 9 aromatic or heteroaromatic rings, wherein one or more of the aromatic or heteroaromatic rings may be substituted by C1 to C4 alkyl. In this regard, aromatic, correspondingly heteroaromatic rings are single aromatic rings, such as 6-membered aromatic rings such as phenyl, 6-membered heteroaromatic rings such as pyridyl, 5-membered heteroaromatic rings such as pyrrolyl, etc. In the system of condensed (hetero) aromatic rings, each ring is considered to be a single ring in this regard. For example, naphthalene includes two aromatic rings.

[0205] Compound (III) may contain at least one heteroaromatic ring, optionally 1 to 5 heteroaromatic rings, optionally 1 to 4 heteroaromatic rings, optionally 1 to 3 heteroaromatic rings and optionally 1 or 2 heteroaromatic rings.

[0206] The aromatic or heteroaromatic ring of compound (III) may be a 6-membered ring.

[0207] The heteroaromatic rings of compound (III) may be N-containing heteroaromatic rings, optionally all heteroaromatic rings are N-containing heteroaromatic rings, optionally all heteroaromatic rings contain N as the only type of heteroatom.

[0208] Compound (III) may comprise at least one 6-membered heteroaromatic ring containing 1 to 3 N atoms in each heteroaromatic ring, and optionally 1 to 3 6-membered heteroaromatic rings containing 1 to 3 N atoms in each heteroaromatic ring.

[0209] The at least one 6-membered heteroaromatic ring contained in the compound (III) may be an oxazine, a triazine, a diazine, or a pyrazine.

[0210] If compound (III) contains two or more heteroaromatic rings, the heteroaromatic rings may be separated from one another by at least one aromatic ring which does not contain heteroatoms.

[0211] In one embodiment, the heteroatom in the heteroaromatic ring of compound (III) is bonded to the molecular structure of compound (III) via at least one double bond.

[0212] The molecular dipole moment of compound (III) calculated by TURBOMOLE V6.5 package using hybrid functional B3LYP and Gaussian6-31G* basis set can be ≥0D and ≤4D; or ≥0.1D and ≤3.9D; or ≥0.2D and ≤3.7D; or ≥0.3D and ≤3.5D.

[0213] By selecting compound (III) according to these embodiments, the mobility of the second electron transport layer can be further improved, the voltage of the OLED device can be reduced, and the cd / A efficiency of the OLED device can be increased.

[0214] In one embodiment, compound (III) is not a compound of formula (II). The compound of formula (III) may be selected from compounds C-1 to C-6 in Table 4 below.

[0215] Table 4:

[0216]

[0217]

[0218]

[0219] In the case where the second electron transport layer comprises both the compound of formula (II) and compound (III), the weight ratio of formula (II) to compound (III) can be 1:99 to 99:1, or 10:90 to 60:40, or 20:80 to 50:50, or 25:75 to 40:60, or about 30:70.

[0220] In one embodiment, the LUMO energy level of compound (III) is calculated by TURBOMOLE V6.5 package using hybrid functional B3LYP and Gaussian6-31G* basis set, with the vacuum level as zero absolute scale, and is in the range of -2.00 eV to -1.70 eV, preferably -1.95 eV to -1.80 eV.

[0221] In one embodiment, compound (III) comprises a nitrogen-containing six-membered ring.

[0222] In another embodiment, compound (III) comprises two nitrogen-containing six-membered rings.

[0223] In one embodiment, the compound of formula (I) is not the compound of formula (II). In another embodiment, the compound of formula (II) is not compound (III). In another embodiment, the compound of formula (I) is not compound (III). In another embodiment of the present invention, all three compounds, i.e., the compound of formula (I), the compound of formula (II) and compound (III) are different from each other because they have different molecular structural formulas.

[0224] The second electron transport layer may be arranged between the first electron transport layer and the electron injection layer. The second electron transport layer may be arranged to be in direct contact with the first electron transport layer. The second electron transport layer may be arranged to be in direct contact with the electron injection layer. The second electron transport layer may be arranged to be in direct contact with the cathode.

[0225] The second electron transport layer may be arranged as a "contact sandwich" between the first electron transport layer and the electron injection layer.

[0226] The second electron transport layer may be disposed between the first electron transport layer and the charge generation layer. The second electron transport layer may be disposed in direct contact with the charge generation layer. The second electron transport layer may be disposed in direct contact with the n-type CGL.

[0227] The second electron transport layer may be arranged as a "contact sandwich" between the first electron transport layer and the n-type CGL.

[0228] The second electron transport layer may have a thickness of <100 nm, optionally between 10 nm and 90 nm, optionally between 10 nm and 60 nm, optionally between 10 nm and 50 nm.

[0229] First charge generation layer

[0230] The first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer. The first charge generation layer comprises a compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer. In other words, a specific compound of formula (II) is selected for use in the first charge generation layer, and then the exact same specific compound of formula (II) is also used as the compound of formula (II) in the second electron transport layer. In other words, "same compound" in this regard refers to a compound having the same chemical formula, including the case of the same isomer.

[0231] The second electron transport layer may be in direct contact with the first charge generation layer. The charge generation layer may include a p-type sublayer and an n-type sublayer, and the second electron transport layer may be in direct contact with the n-type sublayer. The intermediate layer may be arranged between the p-type layer and the n-type layer. The intermediate layer may be in direct contact with the p-type layer or the n-type layer. The intermediate layer may be in direct contact with the p-type layer and the n-type layer.

[0232] The first electron transport layer stack may be disposed between the first light emitting layer and the first charge generating layer.

[0233] The first charge generation layer comprises a metal, or an alkali metal, a metal salt, or an alkaline earth metal salt and / or a rare earth metal salt, or an organic alkali metal complex, or an alkali metal complex, or LiF, LiCl, LiBr, LiI, LiQ, a metal borate, or a mixture thereof. The metal cation of the metal salt may be selected from alkali metals, alkaline earth metals and rare earth metals, or from Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba; or from Li, Mg, Ca and Sr. The anion of the metal salt may be selected from quinoline anions, phosphine oxide phenol anions and borate anions. The compounds are disclosed, for example, in EP 1837926 A1, WO 07107306 A1 or WO 07107356 A1.

[0234] The first charge generation layer may have a thickness in the range of 5 nm to 20 nm, for example 10 nm to 20 nm, for example about 15 nm.

[0235] Other Viable Properties of OLEDs

[0236] The organic light emitting diode according to the present invention comprises at least two light emitting layers, namely a first light emitting layer and a second light emitting layer. In addition, the organic light emitting diode may comprise other light emitting layers (a third light emitting layer, a fourth light emitting layer, etc.). In the case where the organic light emitting diode comprises more than two light emitting layers, only one electron transport layer stack may be provided between the two light emitting layers. Alternatively, there may be more than one electron transport layer stack. For example, in the case where the organic light emitting diode comprises a first light emitting layer, a second light emitting layer and a third light emitting layer, the first electron transport layer stack may be arranged between the first light emitting layer and the second light emitting layer, and the second electron transport layer stack may be arranged between the second light emitting layer and the third light emitting layer.

[0237] In the case where the organic light emitting diode comprises more than two light emitting layers, more than one charge generation layer may be present. For example, in the case where the organic light emitting diode comprises a first light emitting layer, a second light emitting layer and a third light emitting layer, the first charge generation layer may be arranged between the first light emitting layer and the second light emitting layer, and the second charge generation layer may be arranged between the second light emitting layer and the third light emitting layer.

[0238] In the case where the organic light emitting diode comprises more than two light emitting layers, more than one charge generation layer may be present. For example, in the case where the organic light emitting diode comprises a first light emitting layer, a second light emitting layer and a third light emitting layer, the first charge generation layer may be arranged between the first light emitting layer and the second light emitting layer, and the second charge generation layer may be arranged between the second light emitting layer and the third light emitting layer.

[0239] For the purposes of the present invention, a stack is an arrangement of two or more different layers. The layers of the stack can be distinguished from each other by the chemical nature of the materials contained in the respective layers, i.e., can be made of different compounds. The electron transport layer stack according to the present invention comprises at least two different layers, each made of an electron transport material.

[0240] The compound of formula (I) and / or the compound of formula (II) and / or the compound of formula (III) may be different from each other. That is, the compound of formula (I) and / or the compound of formula (II) and / or the compound of formula (III) may be different from each other in at least one structure, in particular, may have at least one atom and / or group that is different from each other.

[0241] The first electron transport layer and the second electron transport layer do not contain an electrical dopant. In this regard, "do not contain" means that the corresponding compound (electrical dopant) is only contained in the corresponding layer, which cannot be avoided by standard purification methods and commonly used technical means during the preparation of the corresponding layer. In this regard, the electrical dopant is particularly but not limited to an n-type electrical dopant. The n-type electrical dopant may be selected from: a metal or an alkali metal; a metal salt or an alkaline earth metal salt and / or a rare earth metal salt; or an organic alkali metal complex or an alkali metal complex; or LiF, LiCl, LiBr, LiI, LiQ, a metal borate; or a mixture thereof. In particular, the first electron transport layer and the second electron transport layer may not contain an n-type electrical dopant. The n-type electrical dopant may be a metal salt comprising at least one metal cation and at least one anion. The metal cation of the metal salt may be selected from alkali metals, alkaline earth metals and rare earth metals; or selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba; or selected from Li, Mg, Ca and Sr. The anion of the metal salt may be selected from quinoline anions, phosphine oxide phenol anions and borate anions.

[0242] In this regard, the n-type electrical dopant is in particular, but not limited to, an elemental metal, or an electropositive metal selected from alkali metals, alkaline earth metals, rare earth metals and transition metals, a transition metal; a metal salt, or an alkali metal salt, an alkaline earth metal salt and / or a rare earth metal salt; or a metal complex, or an alkali metal complex, an alkaline earth metal complex, a transition metal complex and / or a rare earth metal complex. Examples of n-type doping metal salts can be LiF, LiCl, LiBr, LiI, metal borates, metal quinolates or mixtures thereof. Other examples of n-type electrical dopants are strong chemical reducing agents. A general feature of this type of "redox" n-type dopant can be that the energy level of the highest occupied molecular orbital (HOMO) is comparable to the energy level of the lowest unoccupied molecular orbital of the corresponding electron transport matrix, which is about -3.0 eV or less in typical OLED transport materials. It should be understood that the term "about -3.0 eV or less" refers to a value less negative than -3.0 eV, such as -2.8 eV, -2.5 eV, -2.3 eV, -2.1 eV, or a value less negative than -2.0 eV.

[0243] The n-type electrical dopant may be an organic compound as disclosed in EP1837926A1, WO07107306A1 or WO07107356A1.

[0244] It may be provided that the electrical dopant is substantially non-luminescent.

[0245] The first electron transport layer stack may be disposed between the first light emitting layer and the first charge generating layer.

[0246] The first electron transport layer and the second electron transport layer may be in direct contact with each other.

[0247] The electron transport layer stack may consist of a first electron transport layer and a second electron transport layer.

[0248] The second electron transport layer may be in direct contact with the electron injection layer.

[0249] The electron injection layer may consist of a plurality of separate electron injection sublayers.

[0250] The electron injection layer may contain: a metal or an alkali metal, a metal salt or an alkaline earth metal salt and / or a rare earth metal salt, or an organic alkali metal complex or an alkali metal complex, or LiF, LiCl, LiBr, LiI, LiQ, a metal borate, or a mixture thereof.

[0251] The electron injection layer may be composed of a metal or an alkali metal, a metal salt or an alkaline earth metal salt and / or a rare earth metal salt, or an organic alkali metal complex or an alkali metal complex, or LiF, LiCl, LiBr, LiI, LiQ, a metal borate, or a mixture thereof.

[0252] It may be provided that the compound of formula (II) is not contained in the electron injection layer. It may be provided that the compound of formula (I) is not contained in the electron injection layer. It may be provided that the compound (III) is not contained in the electron injection layer.

[0253] The compound of formula (I), the compound of formula (II), and the compound of formula (III) may be different from each other and / or may not be contained in the electron injection layer, respectively.

[0254] The first electron transport layer stack may be disposed between the first light emitting layer and the first charge generating layer. The second electron transport layer of the first electron transport layer stack may be in direct contact with the first charge generating layer.

[0255] The first electron transport layer and the second electron transport layer may be in direct contact with each other.

[0256] The electron transport layer stack may consist of a first electron transport layer and a second electron transport layer.

[0257] The organic light emitting diode may further comprise an electron injection layer and a second electron layer stack, and the second electron layer stack is in direct contact with the electron injection layer. The second electron transport layer stack may contain the same compounds (I), (II) and (III) as the first layer stack, i.e., as defined in the present disclosure, wherein the corresponding compounds may be independently selected.

[0258] It may be provided that the compound of formula (II) is not contained in the first charge generation layer. It may be provided that the compound of formula (I) is not contained in the first charge generation layer. It may be provided that the compound (III) is not contained in the first charge generation layer.

[0259] The compound of formula (I), the compound of formula (II), and the compound (III) may be different from each other and / or may not be contained in the first charge generation layer.

[0260] Where the organic light emitting device comprises more than one electron transport layer stack (ie, other electron transport layer stacks in addition to the first electron transport layer stack), all of the above features with respect to the first electron transport layer stack may apply independently to each electron transport layer stack.

[0261] In case the organic light emitting device comprises more than one charge generation layer (ie, further charge generation layers in addition to the first charge generation layer), all the above features with respect to the first charge generation layer may apply independently to each charge generation layer.

[0262] The organic light emitting diode may further comprise a substrate, wherein the substrate may be transparent or opaque.

[0263] Exemplary Embodiments

[0264] According to one embodiment, an organic light emitting diode is provided, the organic light emitting diode comprising an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generation layer and a first electron transport layer stack; wherein

[0265] - the first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer;

[0266] - the first electron transport layer stack is arranged between the first light-emitting layer and the second light-emitting layer;

[0267] - the first electron transport layer stack comprises a first electron transport layer and a second electron transport layer;

[0268] - The first electron transport layer comprises a compound of formula (I)

[0269] (Ar 1 -A c ) a -X b (I);

[0270] -a and b are independently 1 or 2;

[0271] -c is independently 0 or 1;

[0272] -Ar 1 Independently selected from C6 to C 30 Aryl or C2 to C 24 Heteroaryl,

[0273] - Each Ar 1may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0274] -Ar 1 Each C6 to C 12 Aryl substituents and Ar 1 Each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen;

[0275] -A is independently selected from C6 to C 18 Aryl,

[0276] - wherein each A may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0277] - Each C6 to C on A 12The aryl substituents may be substituted with C1 to C4 alkyl or halogen;

[0278] -X is independently selected from C3 to C 21 Heteroaryl and C6 to C 24 Aryl,

[0279] - wherein each X may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0280] - where each C6 to C on X 12 The aryl substituent and each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen;

[0281] - the molecular dipole moment of the compound of formula (I) is ≥0D and ≤3.5D;

[0282] The second electron transport layer comprises a compound of formula (II)

[0283] (Ar 2 ) m -(Z k -G) n (II);

[0284] - m and n are independently 1 or 2;

[0285] - k is independently 0, 1 or 2;

[0286] -Ar 2 Independently selected from C3 to C 30 Heteroaryl and C6 to C 42 Aryl,

[0287] - Each Ar 2may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0288] -Ar 2 Each C6 to C 12 Aryl substituents and Ar 2 Each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen;

[0289] -Z is independently selected from C6 to C 18 Aryl,

[0290] - wherein each Z may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy;

[0291] - where each C6 to C on Z 12The aryl substituents may be substituted with C1 to C4 alkyl or halogen;

[0292] - G is selected so that the dipole moment of the compound G-phenyl is ≥ 2D and ≤ 6D;

[0293] - the first electron transport layer and the second electron transport layer do not contain electrical dopants;

[0294] - the first charge generation layer comprises the compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer; and

[0295] -G contains the portion P=O.

[0296] According to one embodiment, an organic light emitting diode is provided, the organic light emitting diode comprising an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generation layer and a first electron transport layer stack; wherein

[0297] - the first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer;

[0298] - the first electron transport layer stack is arranged between the first light-emitting layer and the second light-emitting layer;

[0299] - the first electron transport layer stack comprises a first electron transport layer and a second electron transport layer;

[0300] - The first electron transport layer comprises a compound of formula (I)

[0301] (Ar 1 -A c ) a -X b (I);

[0302] -a and b are independently 1 or 2;

[0303] -c is independently 0 or 1;

[0304] -Ar 1 is independently selected from phenyl, naphthyl, anthracenyl, fluoranthenyl, xanthene, dibenzofuranyl, pyrimidinyl, pyrazinyl, spiro-xanthene, fluorenyl, spiro-fluorenyl, triphenylsilyl, tetraphenylsilyl or a group having formula (IIa) or (IIb),

[0305]

[0306] in

[0307] - the asterisk symbol "*" indicates the binding position of the group of formula (IIa) to A; and

[0308] -R 1 To R 9 Independently selected from H, C6 to C 12 Aryl and C4 to C 10 heteroaryl;

[0309] -A is independently selected from a benzene group, a naphthalene group, a biphenyl group and a terphenyl group, each of which may be substituted or unsubstituted;

[0310] -X is independently selected from C2 to C 39 Containing N heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Containing N heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30 Containing N heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Containing N heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Containing N heteroaryl and C6 to C 30 Aryl, and optionally C3 to C 21 Containing N heteroaryl and C6 to C 24 Aryl. In this regard, it can be provided that the corresponding N-containing heteroaryl group contains one or more N atoms as the only (one or more) heteroatoms;

[0311] The second electron transport layer comprises a compound of formula (II)

[0312] (Ar 2 ) m -(Z k -G) n (II);

[0313] - m and n are independently 1 or 2;

[0314] - k is independently 0, 1 or 2;

[0315] -Ar 2 Independently selected from C2 to C 39 Containing N heteroaryl and C6 to C 54 Aryl, optionally C2 to C 36 Containing N heteroaryl and C6 to C 48 Aryl, optionally C3 to C 30 Containing N heteroaryl and C6 to C 42 Aryl, optionally C3 to C 27 Containing N heteroaryl and C6 to C 36 Aryl, optionally C3 to C 24 Containing N heteroaryl and C6 to C 30Aryl, and optionally C3 to C 21 Containing N heteroaryl and C6 to C 24 Aryl. In this regard, it can be provided that the corresponding N-containing heteroaryl group contains one or more N atoms as the only (one or more) heteroatoms;

[0316] -Z is independently selected from C6 to C 30 Aryl, or C6 to C 24 Aryl, or C6 to C 18 Aryl, or C6 to C 12 aryl, said groups may be substituted or unsubstituted, respectively;

[0317] -G is selected from the group consisting of a dialkylphosphinyl group, a diarylphosphinyl group, a diheteroarylphosphinyl group, an alkylarylphosphinyl group, an alkylheteroarylphosphinyl group, an arylheteroarylphosphinyl group, an aryl group substituted by a dialkylphosphinyl group, an aryl group substituted by a diarylphosphinyl group, an aryl group substituted by a diheteroarylphosphinyl group, an aryl group substituted by an alkylarylphosphinyl group, an aryl group substituted by an alkylheteroarylphosphinyl group, and an aryl group substituted by an arylheteroarylphosphinyl group;

[0318] - the first electron transport layer and the second electron transport layer do not contain electrical dopants;

[0319] - the first charge generation layer comprises the compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer; and

[0320] -G contains the portion P=O.

[0321] According to one embodiment, an organic light emitting diode is provided, the organic light emitting diode comprising an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generation layer and a first electron transport layer stack; wherein

[0322] - the first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer;

[0323] - the first electron transport layer stack is arranged between the first light-emitting layer and the second light-emitting layer;

[0324] - the first electron transport layer stack comprises a first electron transport layer and a second electron transport layer;

[0325] - The first electron transport layer comprises a compound of formula (I)

[0326] (Ar 1 -A c ) a -X b (I);

[0327] -a and b are independently 1 or 2;

[0328] -c is independently 0 or 1;

[0329] -Ar 1 independently selected from fluoranthenyl, dibenzofuranyl, pyrimidinyl, pyrazinyl, 9,9-dimethylfluorenyl, a group having formula (IIa), a group having formula (IIb),

[0330]

[0331] in

[0332] - the asterisk symbol "*" indicates the binding position of the group of formula (IIa) to A; and

[0333] -R 1 is H, and R 2 To R 5 are independently phenyl; or

[0334] -R 1 and R 3 is phenyl, and R 2 , R 4 and R 5 is H; or

[0335] -R 6 To R 9 is phenyl;

[0336] -A is independently selected from a benzene group, a naphthalene group, a biphenyl group and a terphenyl group, each of which may be substituted or unsubstituted;

[0337] -X is independently selected from the group consisting of triazine, 1,2-diazine, 1,3-diazine, 1,4-diazine, quinazolinyl, benzoquinazolinyl, benzimidazolyl, quinolinyl, benzoquinolinyl, benzoacridinyl, dibenzoacridinyl, fluoranthenyl, anthracenyl, naphthyl, terphenylidene, phenanthroline and dinaphthofuranyl, each of which may be substituted or unsubstituted;

[0338] The second electron transport layer comprises a compound of formula (II)

[0339] (Ar 2 ) m -(Z k -G) n (II);

[0340] -Ar 2Independently selected from: pyridyl, triazine, 1,2-diazine, 1,3-diazine, 1,4-diazine, quinazolinyl, benzoquinazolinyl, benzimidazolyl, quinolinyl, benzoquinolinyl, benzoacridinyl, dibenzoacridinyl, fluoranthenyl, anthracenyl, naphthyl, terphenylidene, phenanthroline and dinaphthofuranyl, each of which may be substituted or unsubstituted;

[0341] -Z is selected from the group consisting of benzene, naphthalene, benzene-naphthalene, benzene-naphthalene-benzene, benzene-anthracenene-benzene, biphenylene and terphenylene, each of which may be substituted or unsubstituted;

[0342] -G is selected from dialkylphosphinyl and diarylphosphinyl, and can be selected from C1 to C6 dialkylphosphinyl, especially C1 to C4 dialkylphosphinyl, and C6 to C 10 Diarylphosphinyl, for example, can be selected from dimethylphosphinyl (P(=O)(CH3)2) and diphenylphosphinyl (P(=O)(C6H5)2);

[0343] - the first electron transport layer and the second electron transport layer do not contain electrical dopants;

[0344] - the first charge generation layer comprises the compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer; and

[0345] -G contains the portion P=O.

[0346] According to one embodiment, an organic light emitting diode is provided, the organic light emitting diode comprising an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generation layer and a first electron transport layer stack; wherein

[0347] - the first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer;

[0348] - the first electron transport layer stack is arranged between the first light-emitting layer and the second light-emitting layer;

[0349] - the first electron transport layer stack comprises a first electron transport layer and a second electron transport layer;

[0350] - the first electron transport layer comprises a compound selected from compounds A-1 to A-41;

[0351] - the second electron transport layer comprises a compound selected from compounds B-1 to B-45;

[0352] - the first electron transport layer and the second electron transport layer do not contain electrical dopants;

[0353] - the first charge generation layer comprises the compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer; and

[0354] -G contains the portion P=O.

[0355] Other layers

[0356] According to the present invention, in addition to the layers mentioned above, the organic electronic device may include other layers. Exemplary embodiments of each layer are described below:

[0357] Base

[0358] The substrate can be any substrate commonly used to manufacture electronic devices such as organic light emitting diodes. If light is emitted through the substrate, the substrate should be a transparent or translucent material, such as a glass substrate or a transparent plastic substrate. If light is emitted through the top surface, the substrate can be a transparent as well as an opaque material, such as a glass substrate, a plastic substrate, a metal substrate or a silicon substrate.

[0359] Anode electrode

[0360] The first electrode or the second electrode included in the organic electronic device of the present invention can be an anode electrode. The anode electrode can be formed by depositing or sputtering a material for forming the anode electrode. The material for forming the anode electrode can be a high work function material, thereby facilitating hole injection. The anode material can also be selected from a low work function material (i.e., aluminum). The anode electrode can 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 (AlZnO) and zinc oxide (ZnO) can be used to form the anode electrode. Metals, typically silver (Ag), gold (Au), or metal alloys can also be used to form the anode electrode. Transparent or semi-transparent anodes can promote light emission through the anode.

[0361] Hole injection layer

[0362] A hole injection layer (HIL) may be formed on the anode electrode by vacuum deposition, spin coating, printing, casting, slot die coating, Langmuir-Blodgett (LB) deposition, etc. When vacuum deposition is used to form the HIL, the deposition conditions may vary depending on the compound used to form the HIL and the desired structure and thermal properties of the HIL. However, in general, the vacuum deposition conditions may include a deposition temperature of 100° C. to 500° C., a temperature of 10 -8 Up to 10 -3Torr pressure (1 Torr equals 133.322 Pa) and a deposition rate of 0.1 to 10 nm / sec.

[0363] When the HIL is formed using spin coating or printing, the coating conditions may vary according to the compound used to form the HIL and the desired structure and thermal properties of the HIL. For example, the coating conditions may include a coating speed of about 2000 rpm to about 5000 rpm, and a heat treatment temperature of about 80° C. to about 200° C. After coating, heat treatment is performed to remove the solvent.

[0364] The HIL may be formed of any compound generally used to form a HIL. Examples of the compound that can be used to form the HIL include phthalocyanine compounds such as copper phthalocyanine (CuPc), 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), TDATA, 2T-NATA, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylidenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), and polyaniline / poly(4-styrenesulfonate) (PANI / PSS).

[0365] The HIL may include or consist of a p-type dopant, and the p-type dopant may be selected from tetrafluoro-tetracyanoquinodimethane (F4TCNQ), 2,2'-(perfluoronaphthalene-2,6-diylidene)dimalononitrile, 4,4',4"-((1E,1'E,1"E)-cyclopropane-1,2,3-triylidenetris(cyanomethylylidene))tris(2,3,5,6-tetrafluorobenzonitrile), or 2,2',2"-(cyclopropane-1,2,3-triylidene)tris(2-(p-cyanotetrafluorophenyl)acetonitrile), but is not limited thereto. The HIL may be selected from known hole transport materials doped with a p-type dopant. Typical examples are: copper phthalocyanine (CuPc), whose HOMO level is about -5.2 eV, doped with tetrafluoro-tetracyanoquinodimethane (F4TCNQ), whose LUMO level is about -5.2 eV; zinc phthalocyanine (ZnPc) doped with F4TCNQ (HOMO = -5.2 eV); α-NPD (N, N'-bis (naphthalene-1-yl) -N, N'-bis (phenyl) - benzidine) doped with F4TCNQ; α-NPD doped with 2,2'- (perfluoronaphthalene-2,6-diylidene) dimalononitrile. The concentration of the p-type dopant can be selected from 1 to 20 wt%, more preferably from 3 to 10 wt%.

[0366] The thickness of the HIL may be within a range of about 1 nm to about 100 nm, and for example, within a range of about 1 nm to about 25 nm. When the thickness of the HIL is within this range, the HIL may have excellent hole injection characteristics without substantial loss in driving voltage.

[0367] Hole transport layer

[0368] 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, etc. When the HTL is formed by vacuum deposition or spin coating, the conditions for deposition and coating may be similar to those for forming the HIL. However, the conditions for vacuum or solution deposition may vary according to the compound used to form the HTL.

[0369] The HTL may be formed from any compound commonly used to form the HTL. Suitable compounds for use are disclosed in, for example, Yasuhiko Shirota and Hiroshi Kageyama, Chem. Rev. 2007, 107, 953-1010, and are incorporated herein by reference. Examples of compounds 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(naphthalene-1-yl)-N,N'-diphenylbenzidine (α-NPD); and triphenylamine compounds, such as 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA). Among these compounds, TCTA is capable of transporting holes and inhibiting the diffusion of excitons into the EML.

[0370] 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 preferably about 20 nm to about 190 nm, further preferably about 40 nm to about 180 nm, further preferably about 60 nm to about 170 nm, further preferably about 80 nm to about 160 nm, further preferably about 100 nm to about 160 nm, further preferably about 120 nm to about 140 nm. The preferred thickness of the HTL may be 170 nm to 200 nm.

[0371] When the thickness of the HTL is within this range, the HTL may have excellent hole transport characteristics without a substantial loss in driving voltage.

[0372] Electron blocking layer

[0373] The function of the electron blocking layer (EBL) is to prevent electrons from being transferred from the light-emitting layer to the hole transport layer, thereby confining the electrons in the light-emitting layer. As a result, efficiency, operating voltage and / or life are improved. Typically, the electron blocking layer comprises a triarylamine compound. The LUMO energy level of the triarylamine compound may be closer to the vacuum energy level than the LUMO energy level of the hole transport layer. Compared with the HOMO energy level of the hole transport layer, the electron blocking layer may have a HOMO energy level that is further away from the vacuum energy level. The thickness of the electron blocking layer may be selected between 2nm and 20nm.

[0374] If the electron blocking layer has a high triplet energy level, it may also be described as a triplet controlling layer.

[0375] If a phosphorescent green or blue emitting layer is used, the function of the triplet control layer is to reduce the quenching of the triplet state. Thus, a higher luminous efficiency from the phosphorescent emitting layer can be achieved. The triplet control layer is selected from triarylamine compounds whose triplet energy level is higher than the triplet energy level of the phosphorescent emitter in the adjacent emitting layer. Suitable compounds for triplet control layers, in particular triarylamine compounds, are described in EP 2 722 908 A1.

[0376] Emitting Layer (EML)

[0377] The EML can be formed on the HTL by vacuum deposition, spin coating, slot die coating, printing, casting, LB deposition, etc. When the EML is formed using vacuum deposition or spin coating, the conditions for deposition and coating may be similar to those for forming the HIL. However, the conditions for deposition and coating may vary according to the compound used to form the EML.

[0378] It may be provided that the light-emitting layer contains no compounds of the formula (I), formula (II) and / or compound (III).

[0379] The light-emitting layer (EML) may be formed of a combination of a host and a light-emitting dopant. Examples 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"-tri(carbazole-9-yl)-triphenylamine (TCTA), 1,3,5-tri(N-phenylbenzimidazol-2-yl)benzene (TPBI), 3-tert-butyl-9,10-di-2-naphthylanthracene (TBADN), distyrylarene (DSA), and bis(2-(2-hydroxyphenyl)benzothiazole acid) zinc (Zn(BTZ)2).

[0380] The emitter dopant may be a phosphorescent or fluorescent emitter. Phosphorescent emitters and emitters emitting 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.

[0381] Examples of red emitter dopants are PtOEP, Ir(piq)3 and Btp2Ir(acac), but are not limited thereto. These compounds are phosphorescent emitters, however, fluorescent red emitter dopants may also be used.

[0382] Examples of phosphorescent green emitter dopants are Ir(ppy)3 (ppy=phenylpyridine), Ir(ppy)2(acac), Ir(mpyp)3.

[0383] Examples of phosphorescent blue emitter dopants are: F2Irpic, (F2ppy)2Ir(tmd) and Ir(dfppz)3; and terfluorene. Examples of fluorescent blue emitter dopants are 4,4'-bis(4-diphenylaminophenylvinyl)biphenyl (DPAVBi), 2,5,8,11-tetra-tert-butylperylene (TBPe).

[0384] The amount of the luminophore dopant may be in the range of about 0.01 to about 50 parts by weight based on 100 parts by weight of the host. Alternatively, the luminescent layer may be composed of a luminescent polymer. The EML may have a thickness of about 10 nm to about 100 nm, for example, a thickness of about 20 nm to about 60 nm. When the thickness of the EML is within this range, the EML may have excellent luminescence without substantial loss in driving voltage.

[0385] Hole Blocking Layer (HBL)

[0386] A hole blocking layer (HBL) may be formed on the EML to prevent holes from diffusing into the ETL by using vacuum deposition, spin coating, slot die coating, printing, casting, LB deposition, etc. When the EML includes a phosphorescent dopant, the HBL may also have a triplet exciton blocking function.

[0387] When vacuum deposition or spin coating is used to form HBL, the conditions of deposition and coating can be similar to those used to form HIL. However, the conditions of deposition and coating can vary according to the compound used to form HBL. Any compound commonly used to form HBL can be used. Examples of compounds used to form HBL include oxadiazole derivatives, triazole derivatives, and phenanthroline derivatives.

[0388] The thickness of the HBL may be in a range of about 5 nm to about 100 nm, for example, 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 loss in driving voltage.

[0389] Electron Transport Layer (ETL)

[0390] The OLED according to the present invention comprises at least two electron transport layers (ETL). At least two of the electron transport layers are a first electron transport layer and a second electron transport layer as defined herein. In addition, the OLED may comprise other ETLs, which may or may not be as defined above. If the other ETLs are different from those defined above, their characteristics may be as described below.

[0391] According to various embodiments, an OLED may include an electron transport layer stack including at least a first electron transport layer (ETL-1) including a compound of formula (I) and at least a second electron transport layer (ETL-2) including a compound of formula (II).

[0392] By properly adjusting the energy level of a specific layer of the ETL, the injection and transport of electrons can be controlled, and holes can be effectively blocked. Thus, the OLED can have a long lifespan, improved performance, and stability.

[0393] Electron injection layer (EIL)

[0394] An EIL may be formed on the second electron transport layer stack, and the EIL may facilitate the injection of electrons from the cathode, optionally injected into the second electron transport layer stack, and the EIL is preferably formed directly on the second electron transport layer stack, preferably directly on the second electron transport layer of the second electron transport layer stack, and preferably in direct contact with the second electron transport layer of the second electron transport layer stack. Examples of materials used to form the EIL or included in the EIL include 8-hydroxyquinoline lithium (LiQ), LiF, NaCl, CsF, Li2O, BaO, Ca, Ba, Yb, Mg known in the art. Although the deposition and coating conditions for forming the EIL are similar to those for forming the HIL, the deposition and coating conditions may vary depending on the material used to form the EIL. The EIL may include an organic matrix material doped with an n-type dopant. The matrix material may be selected from materials commonly used as matrix materials for electron transport layers.

[0395] The EIL may consist of a plurality of separate EIL sub-layers. In the case where the EIL consists of a plurality of separate EIL sub-layers, the number of sub-layers is preferably 2. The separate EIL sub-layers may include different materials for forming the EIL.

[0396] The thickness of the EIL may be in the range of about 0.1 nm to about 10 nm, for example, in the range of about 0.5 nm to about 9 nm. When the thickness of the EIL is within this range, the EIL may have satisfactory electron injection properties without substantial loss of driving voltage.

[0397] The electron transport stack of the present invention is not part of the electron injection layer.

[0398] Cathode electrode

[0399] If the EIL is present, a cathode electrode is formed on the EIL, preferably directly on the EIL, preferably in direct contact with the EIL. In the sense of the present invention, the cathode and the EIL can be regarded as a functional part capable of injecting electrons into the electron transport layer stack. The cathode electrode can be formed of a metal, an alloy, a conductive compound or a mixture thereof. The cathode electrode can have a low work function. For example, the cathode electrode can 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), etc. Alternatively, the cathode electrode can be formed of a transparent conductive oxide such as ITO or IZO.

[0400] The thickness of the cathode electrode may be in the range of about 5 nm to about 1000 nm, for example, in the range of about 10 nm to about 100 nm. When the thickness of the cathode electrode is in the range of about 5 nm to about 50 nm, even if the cathode electrode is formed of a metal or a metal alloy, it may be transparent or translucent. A transparent or translucent cathode may promote light emission through the cathode.

[0401] It should be understood that the cathode electrode and the electron injection layer are not part of the second electron transport layer or any other part of the electron transport layer stack.

[0402] Charge generation layer

[0403] The charge generation layer (CGL), ie, the first CGL, and any other CGL included in the OLED of the present invention may include a p-type CGL and an n-type CGL. An intermediate layer may be disposed between the p-type layer and the n-type layer.

[0404] Generally, the charge generation layer CGL is a pn junction connecting an n-type charge generation layer (electron generation layer, n-type CGL) and a p-type charge generation layer (hole generation layer, p-type CGL). The n-side of the pn junction generates electrons and injects them into the adjacent layer in the anode direction. Similarly, the p-side of the pn junction generates holes and injects them into the adjacent layer in the cathode direction.

[0405] The charge generation layer is used in a tandem OLED (e.g., the OLED of the present invention) comprising two or more light-emitting layers between a cathode and an anode. In a tandem OLED comprising two light-emitting layers, the n-type charge generation layer provides electrons for a first light-emitting layer arranged near the anode, and the hole generation layer provides holes for a second light-emitting layer arranged between the first light-emitting layer and the cathode.

[0406] The matrix material suitable for the hole generation layer can be a material conventionally used as a hole injection and / or hole transport matrix material. In addition, the p-type dopant for the hole generation layer can adopt conventional materials. For example, the p-type dopant can be one selected from the following: tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), a derivative of tetracyanoquinodimethane, a radial ene derivative, iodine, FeCl3, FeF3 and SbCl5. In addition, the host can be one selected from the following: N,N'-di(naphthalene-1-yl)-N,N-diphenyl-benzidine (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1-biphenyl-4,4'-diamine (TPD) and N,N',N'-tetranaphthyl-benzidine (TNB). The p-type charge generation layer can be composed of CNHAT.

[0407] The n-type charge generation layer can be a layer of a pure n-type dopant such as a positive metal, or can be composed of an organic matrix material doped with an n-type dopant. In one embodiment, the n-type dopant can be an alkali metal, an alkali metal compound, an alkaline earth metal, an alkaline earth metal compound, a transition metal, a transition metal compound, or a rare earth metal. In another embodiment, the metal can be one selected from the following: Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy, and Yb. More specifically, the n-type dopant can be one selected from the following: Cs, K, Rb, Mg, Na, Ca, Sr, Eu, and Yb. The matrix material suitable for the n-type charge generation layer can be a material conventionally used as a matrix material for an electron injection or electron transport layer. The matrix material may be, for example, one selected from the following: N-containing heterocyclic compounds such as triazine compounds or phenanthroline compounds such as compound E or bipyridine or terpyridine compounds, hydroxyquinoline derivatives such as tris(8-hydroxyquinoline)aluminum, benzoxazole derivatives and silacyclopentane derivatives.

[0408] The compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer.

[0409] The hole generation layer may be disposed in direct contact with the n-type charge generation layer.

[0410] The electron transport stack of the present invention is not part of the charge generation layer.

[0411] Organic Light Emitting Diode (OLED)

[0412] According to various embodiments of the present invention, an OLED layer may be provided arranged between the above-mentioned layers, on the substrate or on the top electrode.

[0413] According to one aspect of the present invention, an organic light-emitting diode is provided, comprising: a substrate, an anode, a first hole injection layer, a first hole transport layer, a first electron blocking layer, a first light-emitting layer, a first optional hole blocking layer, a first electron transport layer stack, a first charge generating layer, a hole generating layer, a second hole transport layer, a second electron blocking layer, a second light-emitting layer, a second optional hole blocking layer, a second electron transport layer stack, a second electron injection layer and a cathode.

[0414] According to one aspect of the present invention, an organic light-emitting diode is provided, which includes: a substrate, an anode, a hole injection layer, a first hole transport layer, a first electron blocking layer, a first light-emitting layer, a first electron transport layer stack including a first electron transport layer and a second electron transport layer, a first charge generating layer, a second hole transport layer, a second electron blocking layer, a second light-emitting layer, a second electron transport layer stack including a third electron transport layer (= the first electron transport layer of the second stack) and a fourth electron transport layer (= the second electron transport layer of the second stack), a second charge generating layer, a third hole transport layer, a third electron blocking layer, a third light-emitting layer, a third electron transport layer stack including a fifth electron transport layer (= the first electron transport layer of the third stack) and a sixth electron transport layer (= the second electron transport layer of the third stack), an electron injection layer and a cathode.

[0415] According to one aspect, an OLED may include the following layer structure: a substrate arranged adjacent to an anode electrode, the anode electrode is arranged adjacent to a first hole injection layer, the first hole injection layer is arranged adjacent to a first hole transport layer, the first hole transport layer is arranged adjacent to a first electron blocking layer, the first electron blocking layer is arranged adjacent to a first light-emitting layer, the first light-emitting layer is arranged adjacent to a first charge generation layer, the first charge generation layer is arranged adjacent to a first electron transport layer stack comprising a first electron transport layer and a second electron transport layer, the first electron transport layer stack is arranged adjacent to an electron injection layer, and the electron injection layer is arranged adjacent to a cathode electrode.

[0416] For example, according to Figure 1 The OLED can be formed by the following method, wherein on the substrate 110, in the following order are successively formed: an anode 120, a first hole injection layer 130, a first hole transport layer 140, a first electron blocking layer 145, a first light-emitting layer 150, a first electron transport layer stack 160, a first charge generation layer including an n-type charge generation layer 185 and a hole generation layer 135, a second hole transport layer 141, a second electron blocking layer 146, a second light-emitting layer 151, a second electron transport layer stack 165, a second electron injection layer 181 and a cathode 190.

[0417] For example, according to Figure 2The OLED can be formed by the following method, wherein on the anode 120, the following order is successively formed: a hole injection layer 130, a first hole transport layer 140, a first electron blocking layer 145, a first light-emitting layer 150, a first electron transport layer stack 160 including a first electron transport layer 161 and a second electron transport layer 162, a first charge generation layer 184 including an n-type CGL sublayer 184a and a p-type CGL sublayer 184b, a second hole transport layer 141, a second electron blocking layer 146, a second light-emitting layer 151, a third electron transport layer (= second stack) A second electron transport layer stack 165 comprising a first electron transport layer (= first electron transport layer) 166 and a fourth electron transport layer (= second electron transport layer of the second stack) 167, a second charge generation layer 186 comprising an n-type CGL sublayer 186a and a p-type CGL sublayer 186b, a third hole transport layer 142, a third electron blocking layer 147, a third light emitting layer 152, a third electron transport layer stack 168 comprising a fifth electron transport layer (= first electron transport layer of the third stack) 163 and a sixth electron transport layer (= second electron transport layer of the third stack) 164, an electron injection layer 181 and a cathode 190.

[0418] According to another aspect of the present invention, there is provided a method for manufacturing an organic electronic device, the method using:

[0419] - at least one deposition source, preferably two deposition sources, more preferably at least three deposition sources.

[0420] Applicable deposition methods include:

[0421] - Deposition via vacuum thermal evaporation;

[0422] - deposition via solution processing, preferably said processing is selected from spin coating, printing, casting; and / or

[0423] -Slot die coating.

[0424] In case the second electron transport layer(s) comprise compound (III) and a compound of formula (II), the two compounds may be deposited by co-deposition from two separate deposition sources, or as a premix from a single deposition source.

[0425] According to various embodiments of the present invention, the method may further include forming a light-emitting layer on the anode electrode and forming at least one layer selected from the following between the anode electrode and the first electron transport layer: forming a hole injection layer, forming a hole transport layer or forming an electron hole blocking layer.

[0426] According to various embodiments of the present invention, the method may further include a step for forming an organic light emitting diode (OLED), wherein

[0427] - forming a first anode electrode on the substrate,

[0428] - forming a light emitting layer on the first anode electrode,

[0429] - forming an electron transport layer stack on the light emitting layer, and forming a first charge generating layer on the electron transport layer stack,

[0430] - and finally forming a cathode electrode,

[0431] - forming an optional hole injection layer and a hole transport layer in sequence between the first anode electrode and the light-emitting layer,

[0432] - forming a charge generation layer between the electron transport layer stack and the cathode electrode.

[0433] According to various embodiments, the OLED may have the following layer structure, wherein the layers have the following order:

[0434] an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an emissive layer, an optional hole blocking layer, an electron transport layer stack, an n-type CGL, a p-type CGL, a hole transport layer, an electron blocking layer, an emissive layer, an optional hole blocking layer, an electron transport layer stack, a first charge generation layer comprising an n-type CGL and a p-type CGL, a hole transport layer, an electron blocking layer, an emissive layer, an optional hole blocking layer, an electron transport layer stack, an electron injection layer, and a cathode.

[0435] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising at least one organic light emitting device according to any embodiment described throughout the present application, preferably, the electronic device comprises an organic light emitting diode according to one of the embodiments described throughout the present application. More preferably, the electronic device is a display device or a lighting device.

[0436] In one embodiment, the organic electronic device according to the present invention may further include a layer including a radialene compound and / or a quinodimethane compound.

[0437] In one embodiment, the axialene compound and / or the quinodimethane compound can be substituted by one or more halogen atoms and / or one or more electron withdrawing groups. The electron withdrawing group can be selected from a nitrile group, a haloalkyl group, or a perhaloalkyl group, or a perfluoroalkyl group. Other examples of electron withdrawing groups can be acyl, sulfonyl or phosphoryl groups.

[0438] Alternatively, the acyl group, sulfonyl group and / or phosphoryl group may contain halogenated and / or perhalogenated hydrocarbon groups. In one embodiment, the perhalogenated hydrocarbon group may be a perfluoro hydrocarbon group. Examples of perfluoro hydrocarbon groups may be perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorophenyl, perfluorotolyl; Examples of sulfonyl groups containing halogenated hydrocarbon groups may be trifluoromethylsulfonyl, pentafluoroethylsulfonyl, pentafluorophenylsulfonyl, heptafluoropropylsulfonyl, nonafluorobutylsulfonyl, etc.

[0439] In one embodiment, the radialene and / or quinodimethane compound may be included in a hole injection layer, a hole transport layer, and / or a hole generation layer.

[0440] In one embodiment, the radialene compound may have the formula (XX) and / or the quinodimethane compound may have the formula (XXIa) or (XXIb):

[0441]

[0442] Where R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 11 , R 12 , R 15 , R 16 , R 20 , R 21 are independently selected from the above electron withdrawing groups and R 9 , R 10 , R 13 , R 14 , R 17 , R 18 , R 19 , R 22 , R 23 and R 24 Independently selected from: H, halogen and the above-mentioned electron withdrawing groups.

[0443] Hereinafter, the embodiments will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. Reference will now be made in detail to the exemplary aspects.

[0444] General Definition

[0445] In this specification, when no definition is provided otherwise, "alkyl group" may refer to an aliphatic hydrocarbon group. An alkyl group may refer to a "saturated alkyl group" without any double or triple bonds. The term "alkyl" as used herein should encompass straight chain as well as branched and cyclic alkyl groups. For example, C3-alkyl groups may be selected from n-propyl and isopropyl. Similarly, C4-alkyl groups include n-butyl, sec-butyl and tert-butyl. Similarly, C6-alkyl groups include n-hexyl and cyclohexyl.

[0446] If not explicitly mentioned otherwise, the asterisk symbol "*" as used herein indicates the binding position where the corresponding labeled moiety is bonded to another moiety.

[0447] C n The subscript number n in relates to the total number of carbon atoms in the corresponding alkyl, arylene, heteroarylene or aryl group.

[0448] As used herein, the term "aryl" or "aryl substituent" should encompass: phenyl (C6-aryl); fused aromatic hydrocarbons, such as naphthalene, anthracene, phenanthrene, tetracene, etc. Also encompassed are biphenyl and oligophenyl or polyphenyl, such as terphenyl, phenyl-substituted biphenyl, phenyl-substituted terphenyl (such as tetraphenylphenyl group), etc. "Aryl substituent", correspondingly "heteroaryl substituent" refers to a group connected to two other parts. In this specification, the term "aryl group" or "aryl substituent group" may refer to a group comprising at least one hydrocarbon aromatic part, and all elements of the hydrocarbon aromatic part may have a conjugated p orbital, such as a phenyl group, a naphthyl group, an anthracene group, a phenanthrene group, a pyrenyl group, a fluorenyl group, etc. Also included are spiro compounds, in which two aromatic parts are connected to each other by a spiro atom, such as 9,9'-spirodi[9H-fluorene] base. Aryl or arylene groups can include monocyclic or fused-ring polycyclic (ie, links that share adjacent pairs of carbon atoms) functional groups.

[0449] As used herein, the term "heteroaryl" refers to an aryl group in which at least one carbon atom is replaced by a heteroatom. The term "heteroaryl" may refer to an aromatic heterocycle with at least one heteroatom, and all elements of the hydrocarbon heteroaromatic part may have a p orbital forming a conjugation. The heteroatom may be selected from N, O, S, B, Si, P, Se, preferably selected from N, O and S. The heteroaryl subunit ring may contain at least 1 to 3 heteroatoms. Preferably, the heteroaryl subunit ring may contain at least 1 to 3 heteroatoms independently selected from N, S and / or O. As in the case of "aryl" / "aryl subunit", the term "heteroaryl" includes, for example, spiro compounds in which two aromatic moieties are connected to each other, such as spiro[fluorene-9,9'-xanthene]. Other exemplary heteroaryl groups are diazines, triazines, dibenzofurans, dibenzothiofurans, acridines, benzoacridines and dibenzoacridines, etc.

[0450] As used herein, the term "alkenyl" refers to a group containing a carbon-carbon double bond -CR 1 =CR 2 R 3 .

[0451] As used herein, the term "perhalogenated" refers to a hydrocarbyl group in which all of the hydrogen atoms of the hydrocarbyl group are replaced by halogen (F, Cl, Br, I) atoms.

[0452] As used herein, the term "alkoxy" refers to a structural fragment of the formula -OR, wherein R is a hydrocarbon group, preferably an alkyl group or a cycloalkyl group.

[0453] As used herein, the term "thioalkyl" refers to a structural fragment of the formula -SR, wherein R is a hydrocarbon group, preferably an alkyl group or a cycloalkyl group.

[0454] C n The subscript number n in -heteroaryl refers only to the number of carbon atoms and does not include the number of heteroatoms. In this context, it is clear that a C3 heteroarylene group is an aromatic compound containing three carbon atoms such as pyrazole, imidazole, oxazole, thiazole, etc.

[0455] As used herein, the term "heteroaryl" shall include pyridine, quinoline, benzoquinoline, quinazoline, benzoquinazoline, pyrimidine, pyrazine, triazine, benzimidazole, benzothiazole, benzo[4,5]thieno[3,2-d]pyrimidine, carbazole, xanthene, phenoxazine, benzoacridine, dibenzoacridine, and the like.

[0456] In this specification, the term single bond means a direct bond.

[0457] As used herein, the term "fluorinated" refers to a hydrocarbon group in which at least one hydrogen atom contained in the hydrocarbon group is replaced by a fluorine atom. A fluorinated group in which all of its hydrogen atoms are replaced by fluorine atoms is called a perfluorinated group and is specifically represented by the term "fluorinated".

[0458] According to the present invention, a group is "substituted" by another group if one of the hydrogen atoms contained in the group is replaced by another group, wherein the other group is a substituent.

[0459] According to the invention, the expression "between" regarding a layer being between two other layers does not exclude the presence of a further layer that may be arranged between the one layer and one of the two other layers. According to the invention, the expression "in direct contact" regarding two layers being in direct contact with each other means that no further layer is arranged between the two layers. A layer deposited on top of another layer is considered to be in direct contact with this layer.

[0460] The term "contact sandwich" refers to an arrangement of three layers whereby the middle layer is in direct contact with two adjacent layers.

[0461] With regard to the electron transport layer stack of the invention, the compounds mentioned in the experimental part are most preferred.

[0462] A lighting device can be any device used for illumination, irradiation, signal transmission or projection. They are classified accordingly as lighting, irradiation, signal transmission and projection devices. A lighting device generally consists of the following elements: a source of optical radiation; a device that transmits the radiation flux into space in the desired direction; and a housing that connects the components into a single device and protects the radiation source and the optical transmission system from environmental damage and influences.

[0463] According to another aspect, the organic electroluminescent device according to the invention comprises two or three or more light-emitting layers. OLEDs comprising more than one light-emitting layer are also described as tandem OLEDs or stacked OLEDs.

[0464] Organic electroluminescent devices (OLEDs) can be bottom or top emitting devices. Organic electroluminescent devices (OLEDs) can emit light through a transparent anode or through a transparent cathode.

[0465] A further aspect relates to a device comprising at least one organic electroluminescent device (OLED).

[0466] Devices comprising organic light emitting diodes are, for example, displays or lighting panels.

[0467] In the present invention, the following defined terms shall be applied with these definitions unless different definitions are given in the claims or elsewhere in this specification.

[0468] In the context of the present specification, the term "different" or "different from" in relation to a host material means that the host material differs in its structural formula.

[0469] The terms "OLED" and "organic light emitting diode" are used concurrently and have the same meaning. The term "organic electroluminescent device" as used herein may include an organic light emitting diode as well as an organic light emitting transistor (OLET).

[0470] As used herein, "weight percent," "wt %," "percent by weight," "% weight," and variations thereof refer to a composition, component, substance, or agent expressed as the weight of the component, substance, or agent of the corresponding electron transport layer divided by the total weight of its corresponding electron transport layer, multiplied by 100. It is understood that the amount of the total weight percent of all components, substances, and agents of the corresponding electron transport layer and electron injection layer is selected so that it does not exceed 100 weight percent.

[0471] As used herein, "volume percent," "volume %," "percent by volume," "% volume," and variations thereof refer to a composition, component, substance, or agent expressed as the volume of the component, substance, or agent of the corresponding electron transport layer divided by the total volume of its corresponding electron transport layer, multiplied by 100. It is understood that the amount of the total volume percent of all components, substances, and agents of the cathode layer is selected so that it does not exceed 100 volume percent.

[0472] Whether or not explicitly stated, it is assumed herein that all numerical values ​​are modified by the term "about". As used herein, the term "about" refers to the possible changes in the quantity. Whether or not modified by the term "about", the claims include equivalents of the quantities.

[0473] It must be noted that, as used in this specification and the claims, the singular forms "a," "an," "the," and "said" include plural referents unless the content clearly dictates otherwise.

[0474] The terms "does not contain", "does not contain", and "does not include" do not exclude impurities. Impurities have no technical influence on the purpose achieved by the present invention.

[0475] In the context of this specification, the term "substantially non-luminescent" or "non-luminescent" means that the contribution of a compound or layer to the visible luminescence spectrum from a device is less than 10%, preferably less than 5%, relative to the visible luminescence spectrum. The visible luminescence spectrum is a luminescence spectrum having a wavelength of about ≥380 nm to about ≤780 nm.

[0476] Preferably, the organic semiconductor layer comprising the compound of formula (I) is substantially non-emissive or non-emissive.

[0477] The operating voltage, also called U, is 10 mA / cm2. 2 ) is measured in volts (V).

[0478] Candela / ampere efficiency, also known as cd / A efficiency, is measured at 10 mA / cm2. 2 ) are measured in candela per ampere.

[0479] External quantum efficiency, also called EQE, is measured in percent (%).

[0480] The color space is described by the coordinates CIE-x and CIE-y (International Commission on Illumination 1931). CIE-y is particularly important for blue luminescence. A smaller CIE-y indicates a darker blue. Efficiency values ​​are compared at the same CIE-y.

[0481] The highest occupied molecular orbital (also called HOMO) and the lowest unoccupied molecular orbital (also called LUMO) are measured in electron volts (eV).

[0482] The terms "OLED", "organic light emitting diode", "organic light emitting device", "organic optoelectronic device" and "organic light emitting diode" are used concurrently and have the same meaning.

[0483] The terms "lifetime" and "service life" are used concurrently and have the same meaning.

[0484] The anode and cathode may be described as anode electrode / cathode electrode or anode / cathode or anode electrode layer / cathode electrode layer.

[0485] Room temperature, also called ambient temperature, is 23°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0486] These and / or other aspects and advantages of the present invention will become clear and more readily understood from the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

[0487] Figure 1 is a schematic cross-sectional view of a multi-light-emitting layer organic light emitting diode (OLED) according to an exemplary embodiment of the present invention.

[0488] Figure 2 is a schematic cross-sectional view of a multi-light-emitting layer OLED according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0489] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The exemplary embodiments are described below in order to explain aspects of the present invention by referring to the drawings.

[0490] Herein, when a first element is referred to as being formed or arranged "on" or "above" a second element, the first element may be arranged directly on the second element, or one or more other elements may be arranged between them. When a first element is referred to as being arranged "directly on" or "directly above" a second element, no other elements are arranged between them.

[0491] Figure 11 is a schematic cross-sectional view of an organic light emitting diode (OLED) 200 according to an exemplary embodiment of the present invention. The OLED 200 includes a substrate 110, an anode 120, a first hole injection layer (HIL-1) 130, a first hole transport layer (HTL-1) 140, a first electron blocking layer (EBL-1) 145, a first light emitting layer (EML-1) 150, a first electron transport layer (ETL-1) stack 160 including a first electron transport layer 161 of a first stack and a second electron transport layer 162 of a first stack, an n-type charge generation layer (n-type CGL) 185 and a hole generation layer (p-type Charge generation layer; a first charge generation layer of a p-type GCL) 135, a second hole transport layer (HTL-2) 141, a second electron blocking layer (EBL-2) 146, a second light-emitting layer (EML-2) 151, a second electron transport layer (EIL-2) stack 165 including a third electron transport layer (= first electron transport layer of the second stack) 166 and a fourth electron transport layer (= second electron transport layer of the second stack) 167, an electron injection layer (EIL) 181 and a cathode 190.

[0492] refer to Figure 2 OLED 200 includes an anode 120, a hole injection layer (HIL) 130, a first hole transport layer (HTL-1) 140, a first electron blocking layer (EBL-1) 145, a first light emitting layer (EML-1) 150, a first electron transport layer (ETL-1) stack 160 including a first electron transport layer 161 and a second electron transport layer 162, a first charge generation layer (CGL-1) 184, a second hole transport layer (HTL-2) 141, a second electron blocking layer (EBL-2) 146, a second light emitting layer (EML-2) 151, a first electron transport layer (ETL-1) stack 160 including a first electron transport layer 161 and a second electron transport layer 162, )166 and a fourth electron transport layer (= the second electron transport layer of the second stack) 167, a second charge generation layer (CGL-2) 186, a third hole transport layer (HTL-3) 142, a third electron blocking layer (EBL-3) 147, a third light-emitting layer (EML-3) 152, a third electron transport layer (ETL-3) stack 168 including a fifth electron transport layer (= the first electron transport layer of the third stack) 163 and a sixth electron transport layer (= the second electron transport layer of the third stack) 164, an electron injection layer (EIL) 181 and a cathode 190. Figure 2 The OLED shown in FIG. 1 has a first light emitting part A, a second light emitting part B and a third light emitting part C.

[0493] Despite Figure 1 and Figure 2Although not shown in the figure, a sealing layer may be further formed on the cathode electrode 190 to seal the OLED 200. In addition, various other modifications may be made thereto.

[0494] 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 one or more exemplary embodiments of the present invention.

[0495] Example

[0496] Melting point

[0497] The melting point (mp) was determined as the peak temperature of the DSC curve from the above TGA-DSC measurement or a separate DSC measurement (Mettler Toledo DSC822e, the sample was heated from room temperature to complete melting at a heating rate of 10 K / min under a pure nitrogen flow. An amount of 4 to 6 mg of the sample was placed in a 40 μL Mettler Toledo aluminum pan with a lid and a hole of <1 mm was punched in the lid).

[0498] Glass transition temperature

[0499] The glass transition temperature (Tg) was measured as described in DIN EN ISO 11357, published in March 2010, in a Mettler Toledo DSC 822e differential scanning calorimeter under nitrogen and using a heating rate of 10 K / min.

[0500] Standard starting temperature

[0501] The standard onset temperature (TRO) is determined by loading 100 mg of the compound into a VTE source. As a VTE source, a point source of organic material provided by Kurt J. Lesker Company (www.Lesker.com) or CreaPhys GmbH (http: / / www.creaphys.com) can be used. -5 The VTE source was heated at a constant rate of 15 K / min at a pressure of 100 mbar and the temperature inside the source was measured with a thermocouple. The evaporation of the compound was detected with a QCM detector, which detected the deposition of the compound on the quartz crystal of the detector. The deposition rate on the quartz crystal was The VTE source is measured in units of . To determine the standard onset temperature, the deposition rate is plotted against the VTE source temperature. The standard onset is the temperature at which significant deposition occurs on the QCM detector. To obtain accurate results, the VTE source is heated and cooled 3 times, and only the results of the second and third runs are used to determine the standard onset temperature.

[0502] In order to well control the evaporation rate of the organic compound, the standard starting temperature may be in the range of 200 to 255° C. If the standard starting temperature is below 200° C., the evaporation may be too fast and thus difficult to control. If the standard starting temperature is above 255° C., the evaporation rate may be too low, which may result in a low cycle time and the organic compound in the VTE source may decompose due to long-term exposure to high temperature.

[0503] The standard onset temperature is an indirect measure of the volatility of a compound. The higher the standard onset temperature, the lower the volatility of the compound.

[0504] Reduction potential

[0505] The reduction potential was determined at room temperature using a constant potential device Metrohm PGSTAT30 and software MetrohmAutolab GPES by cyclic voltammetry. The redox potential given under a specific compound is measured as follows: in a dry 0.1M THF solution of the experimental substance degassed with argon, under an argon atmosphere, a 0.1M tetrabutylammonium hexafluorophosphate supporting electrolyte was used between platinum working electrodes, and a pseudo-standard electrode (Metrohm silver rod electrode) consisting of a silver wire covered with silver chloride and directly immersed in the measurement solution was measured at a scan rate of 100mV / s. The first run was completed within the widest range of potentials set on the working electrode, and the range was then appropriately adjusted in subsequent runs. The last three runs were completed by adding ferrocene (0.1M concentration) as a standard. The average value of the potential corresponding to the cathode and anode peaks of the studied compound was calculated after subtracting the average value for the standard Fc + The values ​​reported above were finally obtained by averaging the cathodic and anodic potentials observed for the α / Fc redox couple. All investigated compounds as well as the reported comparative compounds showed clear reversible electrochemical behavior.

[0506] Dipole moment

[0507] Dipole moment of a molecule containing N atoms Given by:

[0508]

[0509] where q i and is the partial charge and position of atom i in the molecule.

[0510] The dipole moments were determined by the semiempirical molecular orbital method.

[0511] The geometry of the molecular structure was optimized in the gas phase using the hybrid functional B3LYP and 6-31G* basis set as implemented in the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany). If more than one conformation was feasible, the conformation with the lowest total energy was selected to determine the bond lengths of the molecule.

[0512] Calculated HOMO and LUMO

[0513] HOMO and LUMO are calculated using the program package TURBOMOLE V6.5 (TURBOMOLE GmbH, Litzenhardtstrasse 19, 76135 Karlsruhe, Germany). The optimized geometry of the molecular structure and the HOMO and LUMO energy levels are determined by applying the hybrid functional B3LYP and 6-31G* basis set in the gas phase. If more than one conformation is feasible, the conformation with the lowest total energy is selected.

[0514] Synthesis steps

[0515] The synthesis of compound B-1 is described in WO 2018 / 215442 A1. The synthesis of compound B-2 is described in WO 2018 / 215355 A1. The synthesis of compound C (=(2-([1,1′-biphenyl]-3-yl)-4-phenyl-6-(3-(10-phenylanthracene-9-yl)phenyl)-1,3,5-triazine)) is described in WO 2020 / 120794 A1.

[0516] General steps in making OLEDs

[0517] Preparation of Comparative Example (Comp Ex)

[0518] For the top-emitting OLED device, a substrate with a size of 150 mm × 150 mm × 0.7 mm was ultrasonically cleaned with a 2% aqueous solution of Deconex FPD211 for 7 minutes, then rinsed with pure water for 5 minutes, and dried in a spin rinse dryer for 15 minutes. -5 Up to 10 -7 Ag was deposited at a pressure of 100 mbar as the anode.

[0519] Then, HT-1 and D-1 were vacuum co-deposited on the anode to form a HIL. Then, HT-1 was vacuum deposited on the HIL to form a HTL. Then, HT-2 was vacuum deposited on the HTL to form an electron blocking layer (EBL).

[0520] Then, a first light emitting layer was formed on the EBL by co-depositing HOST-1 and EMITTER-1.

[0521] Then, the compound of formula (I) is vacuum deposited onto the light emitting layer to form a first electron transport layer.

[0522] Then, a second electron transport layer is formed on the first electron transport layer by depositing a premixture of compound F and compound (III).

[0523] Then, an n-type CGL is formed on the second electron transport layer by co-depositing Compound F and lithium.

[0524] Then, HT-1 and D-1 were vacuum co-deposited on the n-type CGL to form a p-type CGL.

[0525] Then, HT-1 was vacuum deposited on the p-type CGL to form the HTL. Then, HT-2 was vacuum deposited on the HTL to form the EBL.

[0526] Afterwards, a second light emitting layer was formed on the EBL by co-depositing HOST-1 and EMITTER-1.

[0527] Then, the compound of formula (I) is vacuum deposited on the light emitting layer to form a first electron transport layer. Then, a second electron transport layer is formed on the first electron transport layer by depositing compound F and compound (III).

[0528] Then, an n-type CGL is formed on the second electron transport layer by co-depositing Compound F and lithium.

[0529] Then, HT-1 and D-1 were vacuum co-deposited on the n-type CGL to form a p-type CGL.

[0530] Then, HT-1 was vacuum deposited on the HIL to form a HTL. Then, HT-2 was vacuum deposited on the HTL to form an electron blocking layer (EBL).

[0531] Afterwards, a third light emitting layer was formed on the EBL by co-depositing HOST-1 and EMITTER-1.

[0532] Then, the compound of formula (I) is vacuum deposited on the light emitting layer to form a first electron transport layer. Then, a second electron transport layer is formed on the first electron transport layer by depositing a premixture of compound F and compound (III).

[0533] Then, a double-layer electron injection layer was formed on the electron transport layer by first depositing LiQ and then Yb.

[0534] Then, at 10 -7 mbar pressure, from 0.01 to Ag:Mg is evaporated at a rate of to form a cathode.

[0535] A capping layer of HT-3 was formed on the cathode.

[0536] Fabrication of OLED Example 1 and OLED Example 2

[0537] For OLED Example 1 and OLED Example 2, Compound F was replaced by compounds of formula (II), ie, Compounds B-1 and B-2.

[0538] Compound (III) is Compound C in all examples.

[0539] The details of the stack in the top-emitting OLED device are given below. The individual layers are separated by slashes " / ". The layer thicknesses are given in square brackets […] and the mixing ratios in weight % are given in round brackets (…):

[0540] Detailed layer stack used in OLED device - with compound (III):

[0541] Ag[100nm] / HT-1:D-1(volume%92:8)[10nm] / HT-1[24nm] / HT-2[5nm] / H09:BD200(weight%97:3)[20nm] / compound of formula (I)[5nm] / {compound of formula (II) or E}:compound (III)(weight%30:70)[25nm] / {compound of formula (II) or E}:Li(weight%99:1)[15nm] / HT-1:D-1(volume%90:10)[10nm] / HT-1[36nm] / HT-2[5nm] / H09:BD200(weight%97:3)[20nm] / compound of formula (I)[5nm m] / {compound of formula (II) or E}:compound (III) (weight % 30:70) [25nm] / {compound of formula (II) or E}:Li (weight % 99:1) [15nm] / HT-1:D-1 (volume % 90:10) [10nm] / HT-1 [57nm] / HT-2 [5nm] / H09:BD200 (weight % 97:3) [20nm] / compound of formula (I) [5nm] / {compound of formula (II) or E}:compound (III) (weight % 30:70) [30nm] / LiQ [1nm] / Yb [2nm] / Ag:Mg (weight % 90:10) [13nm] / HT-3 [65nm]

[0542] Table 5: List of compounds used

[0543]

[0544] Technical Effects of the Invention

[0545] OLED devices according to the present invention show improved lifetime and efficiency (C Eff ), in particular the lifetime at comparable voltages in a device comprising an electron transport layer stack according to the invention.

[0546] Table 6:

[0547] Performance of an organic electroluminescent tandem device comprising the compound of formula (I) in the first electron transport layer and the compound of formula (II) or comparative compound F in the second electron transport layer and in the first charge generation layer.

[0548] Formula (II) Compound (III) nC CIE-y Relative V <![CDATA[Relative to C Eff > Relative LT F C(70％) F:Li(1%) 0.139 100 100 100 B-1 C(70％) B-1: Li (1%) 0.13 77 133 120 B-2 C(70％) B-2: Li (1%) 0.137 78 134 119

[0549] The features disclosed in the foregoing description and the dependent claims may, both individually and in any combination thereof, thereby in their various forms as material for realizing the aspects of the disclosure set out in the independent claims.

Claims

1. An organic light emitting diode, comprising an anode, a cathode, a first light emitting layer, a second light emitting layer, a first charge generating layer and a first electron transport layer stack; in - the first charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer; - the first electron transport layer stack is arranged between the first light-emitting layer and the second light-emitting layer; - the first electron transport layer stack comprises a first electron transport layer and a second electron transport layer; - The first electron transport layer comprises a compound of formula (I) (Ar 1 -A c ) a -X b (I); -a and b are independently 1 or 2; -c is independently 0 or 1; -Ar 1 Independently selected from C6 to C 60 Aryl or C2 to C 42 Heteroaryl, - Each of Ar 1 may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy; -Ar 1 Each C6 to C 12 Aryl Substituents and Ar 1 Each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen; -A is independently selected from C6 to C 30 Aryl, - wherein each A may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy; - Each C6 to C on A 12 The aryl substituents may be substituted with C1 to C4 alkyl or halogen; -X is independently selected from C2 to C 42 Heteroaryl and C6 to C 60 Aryl, - wherein each X may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy; - where each C6 to C on X 12 The aryl substituent and each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen; - the molecular dipole moment of the compound of formula (I) is ≥0D and ≤4D; The second electron transport layer comprises a compound of formula (II) (The 2 ) m -(Z k -G) n (II); - m and n are independently 1 or 2; - k is independently 0, 1 or 2; -Ar 2 Independently selected from C2 to C 42 Heteroaryl and C6 to C 60 Aryl, - Each of Ar 2 may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl, C3 to C 11 heteroaryl, and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy; -Ar 2 Each C6 to C 12 Aryl Substituents and Ar 2 Each C3 to C 11 The heteroaryl substituent may be substituted with C1 to C4 alkyl or halogen; -Z is independently selected from C6 to C 30 Aryl, - wherein each Z may be substituted by one or two substituents independently selected from the following: C6 to C 12 Aryl and C1 to C6 alkyl, D, C1 to C6 alkoxy, C3 to C6 branched alkyl, C3 to C6 cyclic alkyl, C3 to C6 branched alkoxy, C3 to C6 cyclic alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy, halogen, CN or PY (R 10 )2, wherein Y is selected from O, S or Se, preferably O, and R 10 Independently selected from C6 to C 12 Aryl, C3 to C 12 heteroaryl, C1 to C6 alkyl, C1 to C6 alkoxy, partially or perfluorinated C1 to C6 alkyl, partially or perfluorinated C1 to C6 alkoxy, partially or perdeuterated C1 to C6 alkyl, partially or perdeuterated C1 to C6 alkoxy; - where each C6 to C on Z 12 The aryl substituents may be substituted with C1 to C4 alkyl or halogen; - G is selected so that the dipole moment of the compound G-phenyl is ≥ 1D and ≤ 7D; - the first electron transport layer and the second electron transport layer do not contain electrical dopants; - the first charge generation layer comprises the compound of formula (II), wherein the compound of formula (II) in the first charge generation layer is the same as the compound of formula (II) in the second electron transport layer; and -G contains the portion P=O.

2. The organic light emitting diode according to claim 1, wherein Ar 1 is independently selected from phenyl, naphthyl, anthracenyl, fluoranthenyl, xanthene, dibenzofuranyl, pyrimidinyl, pyrazinyl, spiro-xanthene, fluorenyl, spiro-fluorenyl, triphenylsilyl, tetraphenylsilyl or a group having formula (IIa) or (IIb), in - the asterisk symbol "*" indicates the binding position of the group of formula (IIa) to A; and -R 1 To R 9 Independently selected from H, C6 to C 12 Aryl and C4 to C 10 Heteroaryl.

3. The organic light emitting diode according to claim 1, wherein Ar 1 independently selected from fluoranthenyl, dibenzofuranyl, pyrimidinyl, pyrazinyl, 9,9-dimethylfluorenyl, a group having formula (IIa), a group having formula (IIb), in - the asterisk symbol "*" indicates the binding position of the group of formula (IIa) to A; and -R 1 is H, and R 2 To R 5 are independently phenyl; or -R 1 and R 3 is phenyl, and R 2 , R 4 and R 5 is H; or -R 6 To R 9 It is phenyl.

4. An organic light emitting diode according to any one of the preceding claims, wherein A is selected from the group consisting of: a phenylene group, a naphthalene group, a biphenylene group and a terphenylene group, each of which may be substituted or unsubstituted.

5. An organic light emitting diode according to any one of the preceding claims, wherein X is independently selected from: triazine, 1,2-diazine, 1,3-diazine, 1,4-diazine, quinazolinyl, benzoquinazolinyl, benzimidazolyl, quinolinyl, benzoquinolinyl, benzoacridinyl, dibenzoacridinyl, fluoranthenyl, anthracenyl, naphthyl, terphenylidene, phenanthroline and dinaphthofuranyl, which groups may be substituted or unsubstituted, respectively.

6. An organic light emitting diode according to any one of the preceding claims, wherein Ar 2 Independently selected from: pyridyl, triazine, 1,2-diazine, 1,3-diazine, 1,4-diazine, quinazolinyl, benzoquinazolinyl, benzimidazolyl, quinolinyl, benzoquinolinyl, benzoacridinyl, dibenzoacridinyl, fluoranthenyl, anthracenyl, naphthyl, terphenylidene, phenanthroline and dinaphthofuranyl, and the groups may be substituted or unsubstituted, respectively.

7. The organic light emitting diode according to any one of the preceding claims, wherein G is selected from the group consisting of a dialkylphosphinyl group, a diarylphosphinyl group, a diheteroarylphosphinyl group, an alkylarylphosphinyl group, an alkylheteroarylphosphinyl group, an arylheteroarylphosphinyl group, an aryl group substituted by a dialkylphosphinyl group, an aryl group substituted by a diheteroarylphosphinyl group, an aryl group substituted by an alkylarylphosphinyl group, an aryl group substituted by an alkylheteroarylphosphinyl group, and an aryl group substituted by an arylheteroarylphosphinyl group.

8. An organic light emitting diode according to any one of the preceding claims, wherein G is selected so that the compound G-phenyl is represented by one of the following structures, 9. The organic light-emitting diode according to any one of the preceding claims, wherein the compound of formula (II) is selected from B-1 to B-45, 10. The organic light emitting diode according to any one of the preceding claims, wherein the second electron transport layer further comprises compound (III), wherein the compound (III) comprises 8 to 13 aromatic or heteroaromatic rings. The organic light emitting diode according to claim 10 , wherein the compound (III) comprises 1 to 5 heteroaromatic rings.

12. The organic light emitting diode according to claim 10 or 11, wherein: If the compound (III) contains two or more heteroaromatic rings, the heteroaromatic rings are separated from one another by at least one aromatic ring which does not contain heteroatoms.

13. An organic light emitting diode according to any one of the preceding claims, wherein the first electron transport layer stack is arranged between the first light emitting layer and the first charge generating layer.

14. An organic light emitting diode according to any one of the preceding claims, wherein the first electron transport layer and the second electron transport layer are in direct contact with each other.

15. An organic light emitting diode according to any one of the preceding claims, wherein the second electron transport layer is in direct contact with the first charge generation layer.

16. An organic light emitting diode according to any one of the preceding claims, wherein the first charge generation layer comprises a metal, or an alkali metal or a metal salt.

17. A device comprising an organic light emitting diode according to any one of the preceding claims, wherein the device is a display device or a lighting device and emits light through a transparent cathode.

18. A device comprising the organic light emitting diode according to claims 1 to 16, wherein the device is a display device or a lighting device, and emits light through a transparent anode.

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