Organic electroluminescence device

Patent metadata

Field	Value
Publication number	US-9735385-B2
Application number	US-201214240203-A
Country	US
Kind code	B2
Filing date	Jul 25, 2012
Priority date	Aug 22, 2011
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

The present invention relates to organic electroluminescent devices which comprise a mixture of at least two materials in the electron-transport layer.

First claim

The invention claimed is:

1. An organic electroluminescent device comprising anode, cathode, at least one emitting layer and at least one electron-transport layer which is directly adjacent to the emitting layer on the cathode side, wherein the electron-transport layer comprises a mixture of at least two materials ETM1 and ETM2, where the following conditions apply to ETM1 and ETM2:
a) T 1 (ETM1)>2.2 eV; and
b) T 1 (ETM2)>2.2 eV; and
c) −3.2 eV<LUMO(ETM1)<−2.0 eV; and
d) LUMO(ETM2)>LUMO(ETM1);

where T 1 stands for the lowest triplet energy of the respective material and LUMO stands for the energy of the lowest unoccupied molecular orbital of the respective material, and wherein a compound of one of the formulae (1) to (8) is used as ETM1,

where the following applies to the symbols used:
Ar is, identically or differently on each occurrence, a monovalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 1 ;
Ar 1 is a divalent aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R 1 ;
R 1 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, C(═O)Ar 2 , P(═O)(Ar 2 ) 2 , S(═O)Ar 2 , S(═O) 2 Ar 2 , CR 2 ═CR 2 Ar 2 , CN, NO 2 , Si(R 2 ) 3 , B(OR 2 ) 2 , B(R 2 ) 2 , B(N(R 2 ) 2 ) 2 , OSO 2 R 2 , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which is optionally substituted by one or more radicals R 2 , where one or more non-adjacent CH 2 groups is optionally replaced by R 2 C═CR 2 , C≡C, Si(R 2 ) 2 , Ge(R 2 ) 2 , Sn(R 2 ) 2 , C═O, C═S, C═Se, C═NR 2 , P(═O)(R 2 ), SO, SO 2 , NR 2 , O, S or CONR 2 and where one or more H atoms is optionally replaced by F, Cl, Br, I, CN or NO 2 , or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 2 , or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted b one or more radicals R 2 or a combination of these systems; two or more adjacent substituents R 1 here may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another;
Ar 2 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which is optionally substituted by one or more radicals R 2 ;
R 2 is on each occurrence, identically or differently, H, D, CN or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 C atoms, in which, in addition, H atoms is optionally replaced by F; two or more adjacent substituents R 2 here may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another;
or wherein a ketone of the formula (23) or a phosphine oxide of the formula (24) is used as ETM1,

where Ar has the meaning given above.

2. The organic electroluminescent device according to claim 1 , wherein ETM1 and ETM2 are purely organic materials.

3. The organic electroluminescent device according to claim 1 , wherein the triplet energy T 1 of ETM1 and ETM2 and of any further materials present in the electron-transport layer is >2.4 eV.

4. The organic electroluminescent device according to claim 1 , wherein the LUMO of ETM1 is in the range from −3.1 eV to −2.2 eV.

5. The organic electroluminescent device according to claim 1 , wherein the triplet energy T 1 of ETM1 and ETM2 and of any further materials present in the electron-transport layer is >2.6 eV and wherein the LUMO of ETM1 is in the range from −3.0 eV to −2.4 eV.

6. The organic electroluminescent device according to claim 1 , wherein the LUMO of ETM2 is at least 0.1 eV greater than the LUMO of ETM1.

7. The organic electroluminescent device according to claim 1 , wherein the HOMO of ETM1 is <−5.3 eV.

8. The organic electroluminescent device according to claim 1 , wherein HOMO (ETM1)<HOMO (EML) and HOMO (ETM2)<HOMO (EML), where HOMO (EML) represents the HOMO of the emitting layer or of the material of the emitting layer which has the highest HOMO.

9. The organic electroluminescent device according to claim 1 , wherein the proportion of ETM2 is ≧10% by vol. and furthermore the proportion of ETM2 is ≦90% by vol.

10. The organic electroluminescent device according to claim 1 , wherein the proportion of ETM2 is ≧30% by vol. and furthermore the proportion of ETM2 is ≦80% by vol.

11. The organic electroluminescent device according to claim 1 , wherein the electron-transport layer comprises no further materials apart from ETM1 and ETM2.

12. The organic electroluminescent device according to claim 1 , wherein ETM2 is a pure hydrocarbon, or in that ETM2 is a carbazole derivative, a diazasilole derivative or a tetraazasilole derivative.

13. The organic electroluminescent device according to claim 1 , wherein ETM2 is an aromatic hydrocarbon, or in that ETM2 is a carbazole derivative, a diazasilole derivative or a tetraazasilole derivative.

14. The organic electroluminescent device according to claim 1 , wherein ETM2 is selected from compounds of the formulae (36), (37) and (38),

where
R 1 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, C(═O)Ar 2 , P(═O)(Ar 2 ) 2 , S(═O)Ar 2 , S(═O) 2 Ar 2 , CR 2 ═CR 2 Ar 2 , CN, NO 2 , Si(R 2 ) 3 , B(OR 2 ) 2 , B(R 2 ) 2 , B(N(R 2 ) 2 ) 2 , OSO 2 R 2 , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which is optionally substituted by one or more radicals R 2 , where one or more non-adjacent CH 2 groups is optionally replaced by R 2 C═CR 2 , C≡C, Si(R 2 ) 2 , Ge(R 2 ) 2 , Sn(R 2 ) 2 , C═O, C═S, C═Se, C═NR 2 , P(═O)(R 2 ), SO, SO 2 , NR 2 , O, S or CONR 2 and where one or more H atoms is optionally replaced by F, Cl, Br, I, CN or NO 2 , or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 2 , or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R 2 , or a combination of these systems; two or more adjacent substituents R 1 here may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another;
Ar 2 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which is optionally substituted by one or more radicals R 2 ;
R 2 is on each occurrence, identically or differently, H, D, CN or an aliphatic, aromatic and/or heteroaromatic organic radical having 1 to 20 C atoms, in which, in addition, H atoms is optionally replaced by F; two or more adjacent substituents R 2 here may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another;
Ar 3 is on each occurrence, identically or differently, an aromatic ring

Assignees

• Kroeber Jonas Valentin
• Voges Frank
• Heun Susanne
• Kaiser Joachim
• Merck Patent Gmbh

Inventors

• Kroeber Jonas Valentin
• Voges Frank
• Heun Susanne
• Kaiser Joachim

Classifications

• C09B57/00 Primary

  Other synthetic dyes of known constitution · CPC title

• H01L2251/552

  Electricity · mapped topic

• H01L51/0067

  Electricity · mapped topic

• H01L51/5016

  Electricity · mapped topic

• H01L51/5004 Primary

  Electricity · mapped topic