ORGANIC ELECTROLUMINESCENT APPARATUS

Abstract

The present invention relates to an organic electroluminescent device comprising a mixture comprising an electron-transporting host material and a hole-transporting host material, and to a formulation comprising a mixture of the host materials and to a mixture comprising the host materials. The electron-transporting host material corresponds to a compound of the formula (1) from the class of compounds containing a bispirofluorenyl unit.

Claims

1.-15. (canceled)

16. An organic electroluminescent device comprising an anode, a cathode and at least one organic layer, containing at least one light-emitting layer, wherein the at least one light-emitting layer contains at least one compound of formula (1) as host material 1 and at least one compound of formula (2) as host material 2, ##STR01022## where the symbols and indices used are as follows: X is the same or different at each instance and is CR.sup.0 or N, with the proviso that at least two X groups are N; Y is selected from O and S; L is the same or different at each instance and is a single bond or a linker L-1 to L-13, ##STR01023## ##STR01024## where the linkers L-1 to L-13 may also be substituted by one or more substituents R and the dotted line indicates the respective bond to the radical of formula (1); R is the same or different at each instance and is selected from the group consisting of CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms; Ar.sub.1, Ar.sub.2 at each instance are each independently an aryl or heteroaryl group having 5 to 40 aromatic ring atoms which may be substituted by one or more R radicals; A at each instance is independently a group of formula (3) or (4), ##STR01025## Ar at each instance is in each case independently an aryl group having 6 to 40 aromatic ring atoms which may be substituted by one or more R radicals, or a heteroaryl group having 5 to 40 aromatic ring atoms and containing O as heteroatom, which may be substituted by one or more R radicals; * indicates the binding site to formula (2); a, b, c at each instance are each independently 0 or 1, where the sum total of the indices at each instance a+b+c is 1; n and m at each instance are independently 0, 1, 2 or 3; o at each instance is independently 0, 1, 2, 3, 4, 5, 6 or 7; p at each instance is independently 0, 1, 2, 3, 4, 5, 6, 7 or 8; q, r, s, t at each instance are each independently 0 or 1; R.sup.0 at each instance is independently H or an unsubstituted or partly or fully deuterated aromatic ring system having 6 to 18 carbon atoms.

17. The organic electroluminescent device according to claim 16, wherein Y in host material 1 is O.

18. The organic electroluminescent device according to claim 16, wherein host material 2 conforms to one of formulae (2a), (2b) or (2c), ##STR01026## where the symbols and indices A, R, q, r and s used are as defined in claim 16.

19. The organic electroluminescent device according to claim 16, wherein L in host material 1 is a single bond or the linker L-1, L-2 or L-3.

20. The organic electroluminescent device according to claim 16, wherein the device is an electroluminescent device selected from organic light-emitting transistors (OLETs), organic field quench devices (OFQDs), organic light-emitting electrochemical cells (OLECs, LECs, LEECs), organic laser diodes (O-lasers) and organic light-emitting diodes (OLEDs).

21. The organic electroluminescent device according to claim 16, wherein the device comprises, in addition to the light-emitting layer (EML), a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), an electron injection layer (EIL) and/or a hole blocker layer (HBL).

22. The organic electroluminescent device according to claim 16, wherein the light-emitting layer, as well as the at least one host material 1 and the at least one host material 2, contains at least one phosphorescent emitter.

23. The organic electroluminescent device according to claim 22, wherein the phosphorescent emitter conforms to formula (5), ##STR01027## where the symbols and indices for this formula (5) are defined as follows: n+m is 3, n is 1 or 2, m is 2 or 1, X is N or CR, R is H, D, or a branched or linear alkyl group having 1 to 10 carbon atoms or a partly or fully deuterated branched or linear alkyl group having 1 to 10 carbon atoms or a cycloalkyl group which has 4 to 7 carbon atoms and may be partly or fully substituted by deuterium.

24. A process for producing the device according to claim 16, comprising applying the light-emitting layer by gas phase deposition or from solution.

25. The process according to claim 24, wherein the at least one compound of the formula (1) and the at least one compound of the formula (2) are deposited from the gas phase successively or simultaneously from at least two material sources, optionally with the at least one phosphorescent emitter, and form the light-emitting layer.

26. The process according to claim 24, wherein the at least one compound of the formula (1) and the at least one compound of the formula (2) are deposited from the gas phase as a mixture, successively or simultaneously with the at least one phosphorescent emitter, and form the light-emitting layer.

27. The process according to claim 24, wherein the at least one compound of the formula (1) and the at least one compound of the formula (2) are applied from a solution together with the at least one phosphorescent emitter in order to form the light-emitting layer.

28. A mixture comprising at least one compound of formula (1) and at least one compound of formula (2), ##STR01028## where the symbols and indices used are as follows: X is the same or different at each instance and is CR.sup.0 or N, with the proviso that at least two X groups are N; Y is selected from O and S; L is the same or different at each instance and is a single bond or a linker L-1 to L-13, ##STR01029## ##STR01030## where the linkers L-1 to L-13 may also be substituted by one or more substituents R and the dotted line indicates the respective bond to the radical of the formula (1); R is the same or different at each instance and is selected from the group consisting of CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms; Ar.sub.1, Ar.sub.2 at each instance are each independently an aryl or heteroaryl group having 5 to 40 aromatic ring atoms which may be substituted by one or more R radicals; A at each instance is independently a group of formula (3) or (4), ##STR01031## Ar at each instance is in each case independently an aryl group having 6 to 40 aromatic ring atoms which may be substituted by one or more R radicals, or a heteroaryl group having 5 to 40 aromatic ring atoms and containing O as heteroatom, which may be substituted by one or more R radicals; * indicates the binding site to formula (2); a, b, c at each instance are each independently 0 or 1, where the sum total of the indices at each instance a+b+c is 1; n and m at each instance are independently 0, 1, 2 or 3; o at each instance is independently 0, 1, 2, 3, 4, 5, 6 or 7; p at each instance is independently 0, 1, 2, 3, 4, 5, 6, 7 or 8; q, r, s, t at each instance are each independently 0 or 1; X and X.sup.1 at each instance are each independently a bond or C(R#).sub.2; R.sup.0 at each instance is independently H or an unsubstituted or partly or fully deuterated aromatic ring system having 6 to 18 carbon atoms.

29. The mixture according to claim 28, wherein the mixture consists of at least one compound of formula (1), at least one compound of formula (2) and a phosphorescent emitter.

30. A formulation comprising the mixture according to claim 28 and at least one solvent.

Description

EXAMPLE 1

Production of the OLEDs

[0225] Examples C1 to Ex24 which follow (see tables 6 and 7) present the use of the material combinations of the invention in OLEDs by comparison with material combinations from the prior art.

PRETREATMENT FOR EXAMPLES C1 TO EX24

[0226] Glass plaques coated with structured ITO (indium tin oxide) of thickness 50 nm are treated prior to coating, first with an oxygen plasma, followed by an argon plasma. These plasma-treated glass plaques form the substrates to which the OLEDs are applied.

[0227] The OLEDs basically have the following layer structure: substrate/hole injection layer (HIL)/hole transport layer (HTL)/electron blocker layer (EBL)/emission layer (EML)/optional hole blocker layer (HBL)/electron transport layer (ETL)/optional electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer of thickness 100 nm. The exact structure of the OLEDs can be found in table 6. The materials required for production of the OLEDs are shown in table 8. The device data of the OLEDs are listed in table 7. Examples C1 and C4 are comparative examples with an electron-transporting host according to the prior art WO2011088877.

[0228] Examples C2, C3 and C5, C6 are comparative examples with an electron-transporting host according to the prior art, for example known from US20180337348.

[0229] Examples Ex1 to Ex24 show data for OLEDs of the invention.

[0230] All materials are applied by thermal vapour deposition in a vacuum chamber. In this case, the emission layer always consists of at least two matrix materials and an emitting dopant (emitter) which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as SoA1:CoH1:TEG1 (45%:45%:10%) mean here that the material SoA1 is present in the layer in a proportion by volume of 45%, CoH1 in a proportion of 45% and TEG1 in a proportion of 10%. Analogously, the electron transport layer may also consist of a mixture of two materials.

[0231] The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra and current-voltage-luminance characteristics (IUL characteristics) are measured. EQE and current efficiency SE (in cd/A) are calculated therefrom. SE is calculated assuming Lambertian emission characteristics.

[0232] The lifetime LD is defined as the time after which luminance, measured in cd/m.sup.2 in forward direction, drops from the starting luminance to a certain proportion L1 in the course of operation with constant current density j.sub.0. A figure of L1=80% in table 7 means that the lifetime reported in the LD column corresponds to the time after which luminance in cd/m.sup.2 falls to 80% of its starting value.

[0233] Use of Mixtures of the Invention in OLEDs

[0234] The material combinations of the invention can be used in the emission layer in phosphorescent green OLEDs. The inventive combinations of compounds Eg1 to Eg6 in combination with compounds CoH1 and CoH3 are used as matrix material in the emission layer in examples Ex1 to Ex12. The corresponding comparative examples C1 to C6 relate to the compounds SoA1 to SoA3 in combination with the compounds CoH1 and CoH3 that are used as matrix material in the emission layer in examples C1 to C6.

[0235] On comparison of the inventive examples with the corresponding comparative examples (see above), it is clearly apparent that the inventive examples each show a distinct advantage in device lifetime.

TABLE-US-00006 TABLE 6 Structure of the OLEDs HIL HTL EBL EML HBL ETL EIL Ex. thickness thickness thickness thickness thickness thickness thickness C1 HATCN SpMA1 SpMA2 SoA1:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm C2 HATCN SpMA1 SpMA2 SoA2:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm C3 HATCN SpMA1 SpMA2 SoA3:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex1 HATCN SpMA1 SpMA2 Eg1:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex2 HATCN SpMA1 SpMA2 Eg2:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex3 HATCN SpMA1 SpMA2 Eg3:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex4 HATCN SpMA1 SpMA2 Eg4:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex5 HATCN SpMA1 SpMA2 Eg5:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex6 HATCN SpMA1 SpMA2 Eg6:CoH1:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm C4 HATCN SpMA1 SpMA2 SoA1:CoH3:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm C5 HATCN SpMA1 SpMA2 SoA2:CoH3:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm C6 HATCN SpMA1 SpMA2 SoA3:CoH3:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex7 HATCN SpMA1 SpMA2 Eg1:CoH3:TEG1 ST2 ST2:LiQ LIQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex8 HATCN SpMA1 SpMA2 Eg2:CoH3:TEG1 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex9 HATCN SpMA1 SpMA2 Eg3:CoH3:TEG1 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex10 HATCN SpMA1 SpMA2 Eg4:CoH3:TEG1 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex11 HATCN SpMA1 SpMA2 Eg5:CoH3:TEG1 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex12 HATCN SpMA1 SpMA2 Eg6:CoH3:TEG1 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (44%:44%:12%) 10 nm (50%:50%) 1 nm 30 nm 30 nm Ex13 HATCN SpMA1 SpMA2 Eg1:CoH2:TEG2 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex14 HATCN SpMA1 SpMA2 Eg2:CoH2:TEG2 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex15 HATCN SpMA1 SpMA2 Eg3:CoH2:TEG2 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex16 HATCN SpMA1 SpMA2 Eg4:CoH2:TEG2 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex17 HATCN SpMA1 SpMA2 Eg5:CoH2:TEG2 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex18 HATCN SpMA1 SpMA2 Eg6:CoH2:TEG2 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex19 HATCN SpMA1 SpMA2 Eg1:CoH1:TEG3 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex20 HATCN SpMA1 SpMA2 Eg2:CoH1:TEG3 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex21 HATCN SpMA1 SpMA2 Eg3:CoH1:TEG3 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex22 HATCN SpMA1 SpMA2 Eg4:CoH1:TEG3 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex23 HATCN SpMA1 SpMA2 Eg5:CoH1:TEG3 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm Ex24 HATCN SpMA1 SpMA2 Eg6:CoH1:TEG3 ST2 ST2:LiQ LiQ 5 nm 230 nm 20 nm (21%:72%:7%) 5 nm (50%:50%) 1 nm 40 nm 30 nm

TABLE-US-00007 TABLE 7 Data of the OLEDs Ex. j.sub.0 (mA/cm.sup.2) L1 (%) LD (h) C1 40 80 210 C2 40 80 590 C3 40 80 320 Ex1 40 80 705 Ex2 40 80 660 Ex3 40 80 715 Ex4 40 80 670 Ex5 40 80 650 Ex6 40 80 690 C4 40 80 220 C5 40 80 605 C6 40 80 325 Ex7 40 80 720 Ex8 40 80 675 Ex9 40 80 725 Ex10 40 80 680 Ex11 40 80 670 Ex12 40 80 705 Ex13 40 80 1410 Ex14 40 80 1330 Ex15 40 80 1450 Ex16 40 80 1390 Ex17 40 80 1430 Ex18 40 80 1420 Ex19 40 80 1050 Ex20 40 80 920 Ex21 40 80 1090 Ex22 40 80 940 Ex23 40 80 960 Ex24 40 80 1030

TABLE-US-00008 TABLE 8 Structural formulae of the materials used in the OLEDs [01002] [01003] [01004] [01005] [01006] [01007] [01008] [01009] [01010] [01011] [01012] [01013] [01014] [01015] [01016] [01017] [01018] [01019] [01020] [01021]