Electron transport layer and film having improved thermal stability

Patent metadata

Field	Value
Publication number	US-9972792-B2
Application number	US-201615083331-A
Country	US
Kind code	B2
Filing date	Mar 29, 2016
Priority date	Apr 22, 2015
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

Aspects of the invention provide a composition having a blend of an electron transport material and an organo alkali-metal salt wherein the salt has a glass transition greater than 115° C. The organo-alkali metal salt may be selected from the group consisting of lithium 2-(2-pyridyl)phenolate (LiPP), lithium 2-(2′,2″-bipyridine-6′-yl)phenolate (LiBPP), 2-(isoquinoline-10-yl)phenolate (LiIQP), and lithium 2-(2-phenylquinazolin-4-yl)phenolate and lithium 2-(4-phenylquinazolin-2-yl)phenolate. In a preferred embodiment, the organo-alkali metal salt is lithium 2-(2′,2″-bipyridine-6′-yl)phenolate (LiBPP). Aspects of the invention also provide films and devices having a film layer prepared from the composition.

First claim

That which is claimed:

1. A composition for forming an electron transport layer comprising a blend of an electron transport material and an organo-alkali metal salt, the organo-alkali metal salt having a glass transition temperature greater than 115° C., wherein when subjected to an Encapsulation Mimic Test, a film formed from the composition exhibits a percent change in thickness that is less than 20%.

2. The composition of claim 1 , wherein the electron transport material comprises an organic compound having a molecular weight from 350 to 1,000 Daltons.

3. The composition of claim 1 , wherein the electron transport material comprises a polymer.

4. The composition of claim 1 , wherein the blend is characterized by the absence of a binder.

5. The composition of claim 1 , wherein the electron transport material has a HOMO level from about −4.5 to −7.0 eV, a LUMO level from about −1.0 to −2.5 eV, and a triplet energy greater than 1.0 eV.

6. The composition of claim 1 , wherein the composition has a glass transition temperature greater than 125° C.

7. The composition of claim 1 , wherein the organo-alkali metal salt has the following formula:

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 are independently or simultaneously hydrogen, deuterium, a C 1-20 aliphatic hydrocarbon, benzene, naphthalene, biphenyl, a group derived from an aromatic heterocycle or an aromatic ring, or groups forming one or more fused ring structures, and wherein at least one of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 is not a hydrogen.

8. The composition of claim 1 , wherein the organo-alkali metal salt has the following formula:

wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are independently or simultaneously hydrogen, deuterium, a C 1-20 aliphatic hydrocarbon, benzene, phenyl, biphenyl, a group derived from an aromatic heterocycle or an aromatic ring, groups forming one or more fused ring structures, or a halogen;
X is nitrogen;
Y is oxygen, nitrogen, or sulfur;
R 7 is a C 1-4 alkyl group, or a phenyl group, and
n is a number from 1 to 8.

9. The composition of claim 8 , wherein Y is nitrogen, R7 is a methyl, ethyl, or a phenyl, and R 1 -R 6 are hydrogen or deuterium atoms.

10. The composition of claim 1 , wherein the organo-alkali metal salt is selected from the group consisting of lithium 2-(2-pyridyl)phenolate, lithium 2-(2′,2″-bipyridine-6′-yl)phenolate, lithium 2-(isoquinoline-10-yl)phenolate, lithium 2-(2-phenylquinazolin-4-yl)phenolate, and lithium 2-(4-phenylquinazolin-2-yl)phenolate.

11. The composition of claim 1 , wherein when subjected to the Encapsulation Mimic Test, a film formed from the composition exhibits a percent change in thickness that is between 9 and 19%.

12. A film formed of the composition of claim 1 .

13. An article formed from the film of claim 12 .

14. An electronic device comprising a pair of electrodes and at least one electron transfer layer disposed therebetween, the electron transfer layer comprising a blend of an electron transport material and an organo-alkali metal salt, the organo-alkali metal salt having a glass transition temperature greater than 115° C., and wherein a film formed from the blend of an electron transport material and an organo-alkali metal salt when subjected to an Encapsulation Mimic Test exhibits a percent change in thickness that is less than 20%.

15. The device of claim 14 , wherein the organo-alkali metal salt is selected from the group consisting of lithium 2-(2-pyridyl)phenolate, lithium 2-(2′,2″-bipyridine-6′-yl)phenolate, and lithium 2-(isoquinoline-10-yl)phenolate.

16. The device of claim 14 , wherein the blend of the electron transport material and the organo-alkali metal salt has a glass transition temperature of at least 125° C.

17. The device of claim 14 , wherein the device is encapsulated in an epoxy film layer.

18. The device of claim 14 , wherein a film formed from said blend of an electron transport material and an organo-alkali metal salt when subjected to the Encapsulation Mimic Test exhibits a percent change in thickness that is between 10 and 18%.

Assignees

• Dow Global Technologies Llc
• Rohm & Haas Elect Mat

Inventors

• De Vries Timothy S
• Kearns Jr Kenneth L
• Mcintire Travis E
• Mukhopadhyay Sukrit
• Trefonas Iii Peter
• Woodward William H H

Classifications

• H01L51/0067

  Electricity · mapped topic

• H01B1/12 Primary

  organic substances {(organic macromolecular compounds or compositions C08)} · CPC title

• H01L51/5253

  Electricity · mapped topic

• H01L51/0058

  Electricity · mapped topic

• H01L51/0077 Primary

  Electricity · mapped topic