MATERIALS FOR ELECTRONIC DEVICES

Abstract

The present application relates to a material comprising a monoarylamine of a defined formula and a p-dopant of a defined formula. The present application further relates to the use of said material in an organic layer of an electronic device, the device preferably being an organic electroluminescent device (OLED).

Claims

1.-21. (canceled)

22. A material comprising a compound P which is a complex of bismuth and a compound A of a formula (A) ##STR00156## where the variables that occur are: A.sup.1 is the same or different at each instance and is H, an alkyl group which has 1 to 20 carbon atoms and is optionally substituted by one or more R.sup.1 radicals, or Ar.sup.1; Ar.sup.1 is the same or different at each instance and is an aromatic ring system which has 6 to 60 aromatic ring atoms and is optionally substituted by one or more R.sup.1 radicals, or a heteroaromatic ring system which has 5 to 60 aromatic ring atoms and is optionally substituted by one or more R.sup.1 radicals; Ar.sup.1 and/or A.sup.1 groups here is optionally bonded to one another via R.sup.1 radicals; R.sup.1 is the same or different at each instance and is selected from H, D, F, C(═O)R.sup.2, CN, Si(R.sup.2).sub.3, P(═O)(R.sup.2).sub.2, OR.sup.2, S(═O)R.sup.2, S(═O).sub.2R.sup.2, straight-chain alkyl or alkoxy groups having 1 to 20 carbon atoms, branched or cyclic alkyl or alkoxy groups having 3 to 20 carbon atoms, alkenyl or alkynyl groups having 2 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms, and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R.sup.1 radicals is optionally joined to one another and may form a ring; where the alkyl, alkoxy, alkenyl and alkynyl groups mentioned and the aromatic ring systems and heteroaromatic ring systems mentioned may each be substituted by one or more R.sup.2 radicals; and where one or more CH.sub.2 groups in the alkyl, alkoxy, alkenyl and alkynyl groups mentioned is optionally replaced by —R.sup.2C═CR.sup.2—, —C≡C—, Si(R.sup.2).sub.2, C═O, C═NR.sup.2, —C(═O)O—, —C(═O)NR.sup.2—, P(═O)(R.sup.2), —O—, —S—, SO or SO.sub.2; R.sup.2 is the same or different at each instance and is selected from H, D, F, CN, alkyl groups having 1 to 20 carbon atoms, aromatic ring systems having 6 to 40 aromatic ring atoms and heteroaromatic ring systems having 5 to 40 aromatic ring atoms; where two or more R.sup.2 radicals is optionally joined to one another and may form a ring; and where the alkyl groups, aromatic ring systems and heteroaromatic ring systems mentioned is optionally substituted by F or CN; where the scope of the formula (A) excludes compounds of the following formula (B) ##STR00157## in which the new variables that occur are: V is CR.sup.1; Ar.sup.3 is the same or different at each instance and is an aromatic ring system which has 6 to 30 aromatic ring atoms and is optionally substituted by one or more R.sup.1 radicals, or a heteroaromatic ring system which has 5 to 30 aromatic ring atoms and is optionally substituted by one or more R.sup.1 radicals; Ar.sup.1 groups here is optionally bonded to one another via R.sup.1 radicals.

23. The material according to claim 22, wherein the compound A has a single amino group.

24. The material according to claim 22, wherein the compound A does not contain a fused aryl group having more than 10 aromatic ring atoms nor a fused heteroaryl group having more than 14 aromatic ring atoms.

25. The material according to claim 22, wherein both A.sup.1 groups in the compound A are Ar.sup.1.

26. The material according to claim 22, wherein, in the compound A, the Ar.sup.1 group is the same or different at each instance and is an aromatic ring system which has 6 to 40 aromatic ring atoms and is optionally substituted by one or more R.sup.1 radicals, or a heteroaromatic ring system which has 5 to 40 ring atoms and is optionally substituted by one or more R.sup.1 radicals.

27. The material according to claim 22, wherein, in the compound A, the Ar.sup.1 group is a group which is optionally substituted by one or more R.sup.1 radicals and is selected from the group consisting of phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, phenanthryl, fluoranthenyl, fluorenyl, indenofluorenyl, spirobifluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, acridyl and phenanthridyl.

28. The material according to claim 22, wherein the compound P is a complex of bismuth in the (III) oxidation state.

29. The material according to claim 22, wherein the compound P is a complex of bismuth having at least one ligand L which is an organic compound.

30. The material according to claim 29, wherein the ligand L is singly negatively charged.

31. The material according to claim 29, wherein the group in the ligand L that binds to the bismuth atom is selected from carboxylic acid groups, thiocarboxylic acid groups, carboxamide groups and carboximide groups.

32. The material according to claim 29, wherein the ligand L is selected from fluorinated benzoic acid derivatives, fluorinated or non-fluorinated phenylacetic acid derivatives and fluorinated or non-fluorinated acetic acid derivatives.

33. The material according to claim 22, wherein the compound P is present in the material as a dopant in a concentration of 0.1% to 20%.

34. A layer comprising the material according to claim 22.

35. A formulation comprising the material according to claim 22 and at least one solvent.

36. A process for producing the layer according to claim 34, which comprises applying the compound A and compound P together from the gas phase.

37. A process for producing a layer which comprises applying a formulation comprising the material according to claim 22 and a solvent from the liquid phase.

38. An electronic device which is an organic electroluminescent device, organic integrated circuits, organic field-effect transistor, organic thin-film transistor, organic light-emitting transistor, organic solar cell, organic optical detecor, organic photoreceptor, organic field-quench device, organic light-emitting electrochemical cell or organic laser diode, comprising the material according to claim 22.

39. The organic electroluminescent device according to claim 38, wherein the device includes the material in a hole-transporting layer disposed between anode and emitting layer, with one or more further layers present between the layer comprising the material and the emitting layer.

40. The organic electroluminescent device according to claim 39, wherein the HOMO levels of the hole-transporting layer (HTL) and the one layer between hole-transporting layer and emitting layer (EBL) meet the following condition: HOMO(HTL)<=HOMO(EBL).

41. The organic electroluminescent device according to claim 39, wherein the one or more further layers disposed between the layer comprising the material and the emitting layer comprise one or more identical or different compounds of the formula (A).

42. The organic electroluminescent device according to claim 38, wherein the device comprises the material in a layer directly adjoining the anode.

Description

WORKING EXAMPLES

A) Synthesis of bis[[3,5-bis(trifluoromethyl)benzoyl]oxy]bismuthanyl 3,5-bis(trifluoromethyl)benzoate

[0126] ##STR00139##

[0127] 50 g (113.56 mmol) of triphenylbismuthane (CAS No.: 603-33-8) and 89.40 g of 3,5-bis(trifluoromethyl)benzoic acid (340.36 mmol) are initially charged in a flask inertized under argon and 1 l of dried toluene is added. The mixture is heated gradually to 80° C. and then stirred at this temperature for a further 12 hours. The mixture is subsequently cooled to room temperature and filtered through a protective gas frit, washed three times with toluene, dried at the vacuum pump and then sublimed under high vacuum.

B) Device Examples

[0128] In examples 11 to 18 and C1 to C2 which follow, the data of various OLEDs are presented. Examples C1 to C2 are comparative examples according to the prior art; examples 11 to 18 show data of OLEDs of the invention.

[0129] OLEDs of the invention and OLEDs according to the prior art are produced by a general method according to WO 2004/058911, which is adapted to the circumstances described here (variation in layer thickness, materials). Glass plaques which have been coated with structured ITO (indium tin oxide) in a thickness of 50 nm are the substrates for the OLEDs. The substrates are subjected to wet cleaning (cleaning machine, detergent: Merck Extran), then baked at 250° C. for 15 min and, prior to the coating, treated with an oxygen plasma.

[0130] Various layers are applied to the pretreated substrates: first hole transport layer (HTL1)/second hole transport layer (HTL2)/emission layer (EML)/electron transport layer (ETL)/electron injection layer (EIL) and finally a 100 nm-thick aluminium cathode. The exact structure of the OLEDs can be found in Table 1. The materials used for production of the OLEDs are shown in Table 2.

[0131] All materials are applied by thermal vapour deposition in a vacuum chamber. In this case, the emission layer always consists of at least one matrix material and an emitting compound which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as M1:D1 (95%:5%) mean here that the material M1 is present in the layer in a proportion by volume of 95% and D1 in a proportion by volume of 5%. Analogously, the electron transport layer may also consist of a mixture of two materials.

[0132] The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra and the external quantum efficiency (EQE, measured in percent) are determined as a function of luminance, calculated from current-voltage-luminance characteristics (IUL characteristics) assuming Lambertian radiation characteristics, and the lifetime. The electroluminescence spectra are determined at a luminance of 1000 cd/m.sup.2, and the CIE 1931 x and y color coordinates are calculated therefrom. The lifetime LT80 is defined as the time after which the luminance drops from the starting luminance to 80% of the start value in the course of operation with constant current density.

TABLE-US-00001 TABLE 1 Structure of the OLEDs HTL1 HTL2 EML ETL EIL Ex. thickness thickness thickness thickness thickness V1 NPB:BiC NPB M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm V2 DA1:BiC DA1 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E1 MA2:BiC MA2 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E2 MA4:BiC MA4 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E3 MA5:BiC MA5 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E4 MA6:BiC MA6 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E5 MA7:BiC MA7 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E6 MA8:BiC MA8 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E7 MA9:BiC MA9 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm E8 DA2:BiC DA2 M1:D1 ST1:LiQ (50%:50%) LiQ (95%:5%) 20 nm 180 nm (95%:5%) 20 nm 30 nm 1 nm

TABLE-US-00002 TABLE 2 Structural formulae of the materials for the OLEDs [00140] F4TCNQ [00141] BiC [00142] M1 [00143] D1 [00144] ST1 [00145] LiQ [00146] NPB [00147] DA1 [00148] DA2 [00149] MA2 [00150] MA4 [00151] MA5 [00152] MA6 [00153] MA7 [00154] MA8 [00155] MA9

[0133] The examples are elucidated in detail hereinafter, in order to illustrate the advantages of the OLEDs of the invention.

[0134] The inventive samples 11 to 18 are compared with the comparative samples C1 and C2. The former differ from C1 and C2 in that they contain a monoarylamine as material for the HTL, and no diamine or tetraamine. In all cases, the p-dopant BiC is used in the first of the two hole-transporting layers present. All inventive samples 11 to 18 have a better lifetime and efficiency than the comparative samples C1 and C2 (Table 3), with similar values for voltage.

TABLE-US-00003 TABLE 3 Results for the OLEDs Ex. U @ 10 mA/cm.sup.2 EQE @ 10 mA/cm.sup.2 LT80 @ 60 mA/cm.sup.2 C1 4.3 5.7 195 C2 3.8 4.1 50 I1 4.2 8.3 310 I2 4.0 7.1 375 I3 4.2 7.9 365 I4 4.6 7.7 270 I5 4.2 7.0 250 I6 4.3 8.4 270 I7 3.9 7.3 330 I8 4.2 7.8 210

[0135] The examples shown illustrate the advantages of the inventive combination of bismuth complexes with monoarylamines of the formula (A) as hole transport materials in OLEDs. They should not be interpreted in a restrictive manner. The advantages of the inventive combination extend over the whole scope of the material combinations defined in the claims.