Organic electroluminescent device and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-2018175294-A1
Application number	US-201615737179-A
Country	US
Kind code	A1
Filing date	Jun 15, 2016
Priority date	Jun 16, 2015
Publication date	Jun 21, 2018
Grant date	—

Abstract

Disclosed is an organic electroluminescent device, comprising a substrate and light emitting units formed in sequence on the substrate, characterized in that, each of the light emitting units comprises a first electrode layer ( 1 ), a light emitting layer ( 2 ) and a second electrode layer ( 3 ), the light emitting layer comprises a host material and a dye, the host material is made of materials having both electron transport capability and hole transport capability; at least one material in the host material has a CT excited triplet state energy level T 1 greater than its n-π excited triplet state energy level S 1 , and T 1 -S 1 ≤0.3 eV; or, at least one material in the host material has a CT excited triplet state energy level T 1 greater than its n-π excited triplet state energy level S 1 , and T 1 -S 1 ≥1 eV, with the difference between its n-π excited second triplet state energy level and its CT excited first singlet state energy level being in the range of −0.1 eV to 0.1 eV. The organic electroluminescent device configuration can sufficiently utilize the triplet state energy in the host material and the dye to increase the luminous efficiency and prolong the service life of the device.

First claim

1 . An organic electroluminescent device, comprising a substrate and light emitting units formed in sequence on the substrate, wherein each of the light emitting units comprises a first electrode layer ( 1 ), a light emitting layer ( 2 ) and a second electrode layer ( 3 ), the light emitting layer comprises a host material and a dye,
the host material is made of materials having both electron transport capability and hole transport capability; at least one material in the host material has a CT excited triplet state energy level T 1 greater than its n-π excited triplet state energy level S 1 , and T 1 -S 1 ≤0.3 eV; or at least one material in the host material has a CT excited triplet state energy level T 1 greater than its n-π excited triplet state energy level S 1 , and T 1 -S 1 ≥1 eV, with the difference between its n-π excited second triplet state energy level and its CT excited first singlet state energy level being in the range of −0.1 eV to 0.1 eV.

2 . The organic electroluminescent device in accordance with claim 1 , wherein the host material is an exciplex, and the exciplex is a thermal activating delayed fluorescence material.

3 . The organic electroluminescent device in accordance with claim 1 , wherein the host material is an exciplex made from an electron transport type material and a hole transport type material at a mass ratio of 1:9 to 9:1.

4 . The organic electroluminescent device in accordance with claim 3 , wherein
the electron transport type material and/or the hole transport type material has T 1 -S 1 ≤0.3 eV; or the electron transport type material and/or the hole transport type material has T 1 -S 1 ≥1 eV, with the difference between the n-π excited second triplet state energy level and the CT excited first singlet state energy level of the host material being in the range of −0.1 eV to 0.1 eV.

5 . The organic electroluminescent device in accordance with claim 1 , wherein the host material is composed of a thermal activating delayed fluorescence material and a hole transport type material at a mass ratio of 1:9 to 9:1.

6 . The organic electroluminescent device in accordance with claim 5 , wherein
the thermal activating delayed fluorescence material and/or the hole transport type material has T 1 -S 1 ≤0.3 eV; or the thermal activating delayed fluorescence material and/or the hole transport type material has T 1 -S 1 ≥1 eV, with the difference between the n-π excited second triplet state energy level and the CT excited first singlet state energy level of the host material being in the range of −0.1 eV to 0.1 eV.

7 . The organic electroluminescent device in accordance with claim 1 , wherein the host material is composed of a thermal activating delayed fluorescence material and an electron transport type material at a mass ratio of 1:9 to 9:1.

8 . The organic electroluminescent device in accordance with claim 7 , wherein
the thermal activating delayed fluorescence material and/or the electron transport type material has T 1 -S 1 ≤0.3 eV; or the thermal activating delayed fluorescence material and/or the electron transport type material has T 1 -S 1 ≥1 eV, with the difference between the n-π excited second triplet state energy level and the CT excited first singlet state energy level of the host material being in the range of −0.1 eV to 0.1 eV.

9 . The organic electroluminescent device in accordance with claim 1 , wherein the dye is made of a fluorescence material and/or a phosphorescence material, the fluorescence material has a doping concentration of 0.5-10 wt %, the phosphorescence material has a doping concentration of 0.5-20 wt %.

10 . The organic electroluminescent device in accordance with claim 1 , wherein the light emitting layer ( 2 ) has a thickness of 50 nm-150 nm.

11 . The organic electroluminescent device in accordance with claim 1 , wherein,
the electron transport type material is tri-(8-oxyquinoline)-aluminum, 2,9-dimethyl-4,7-diphenyl-1,10-o-phenanthroline, 4,7-diphenyl-1,10-o-phenanthroline, di-(2-methyl-8-quinolyl)-4-phenyl-phenoxide-aluminum(III), 1,3,5-tri-(1-phenyl-1H-benzimidazole-2-yl)-benzene, or 1,3,5-tri-[(3 -pyridyl)-3 -phenyl]-benzene; the hole transport type material is N,N′-di-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine, N,N′-diphenyl-N,N′-di-(m-methyl-phenyl)-1,1′-biphenyl-4,4′-diamine, 4,4′-cyclohexyl-di-[N,N-di-(4-methyl-phenyl)]-phenylamine, 4,4′-N,N′-di-carbazole-biphenyl, 4,4′,4″-tri-(carbazole-9-yl)-triphenylamine, or 1,3-di-(carbazole-9-yl)-benzene. the thermal activating delayed fluorescence (TADF) material has a structure selected from the following structural formulas (1-1) to (1-100):

12 . A preparation method of the organic electroluminescent device of claim 1 , comprising the following steps:
evaporation coating a first electrode layer ( 1 ), a light emitting layer ( 2 ) and a second electrode layer ( 3 ) in sequence on a substrate by using an open mask; wherein the light emitting layer ( 2 ) is prepared by co-evaporation coating of a host material and a dye.

Assignees

• Kunshan Govisionox Optoelectronics Co Ltd
• Univ Tsinghua

Inventors

• Duan Lian
• Zhang Dongdong
• Liu Song
• Xie Jing
• Zhao Fei

Classifications

• C07F1/02

  Lithium compounds · CPC title

• C07D265/38

  [b, e]-condensed with two six-membered rings · CPC title

• C07D417/04

  directly linked by a ring-member-to-ring-member bond · CPC title

• C07C317/36

  with the nitrogen atoms of the amino groups bound to hydrogen atoms or to carbon atoms · CPC title

• C07D417/10

  linked by a carbon chain containing aromatic rings · CPC title