Optical device comprising a charge transport layer of insoluble organic material and method for the production thereof

Patent metadata

Field	Value
Publication number	US-9660212-B2
Application number	US-201514642663-A
Country	US
Kind code	B2
Filing date	Mar 9, 2015
Priority date	Dec 19, 2003
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A method of forming an organic light emitting diode comprising the steps of: providing a substrate comprising a first electrode for injection of charge carriers of a first type; forming a charge transporting layer by depositing over the substrate a charge transporting material for transporting charge carriers of the first type, the charge transporting material being soluble in a solvent; treating the charge transporting layer to render it insoluble in the solvent; forming an electroluminescent layer by depositing onto the charge transporting layer a composition comprising the solvent, a phosphorescent material, and a host material; and depositing over the electroluminescent layer a second electrode for injection of charge carriers of a second type.

First claim

The invention claimed is:

1. A method of forming an organic light emitting diode comprising, in sequence, a first electrode for injection of charge carriers of a first type; a first charge transporting layer comprising a first charge transporting material for transporting charge carriers of the first type; an electroluminescent layer adjacent to the charge transporting layer; and a second electrode for injection of charge carriers of a second type,
the method comprising the steps of:
forming the first charge transporting layer by a solution processing method from a composition comprising a solvent and the first charge transporting material being soluble in the solvent, wherein the first charge transporting material is a small molecule, polymer or dendrimer comprising an optionally substituted triarylamine unit, wherein the first charge transporting material is a hole-transporting material;
rendering the first charge transporting layer insoluble in the solvent by heat treatment at a temperature above the glass transition temperature of the hole-transporting material; and
forming the electroluminescent layer from a composition comprising a solvent, a phosphorescent material and a small molecule host material.

2. A method according to claim 1 , wherein a charge injection layer comprising a conductive organic material for injection of charge carriers of the first type is provided between the first electrode and the first charge transporting layer.

3. A method according to claim 1 , wherein the first charge transporting material has a higher triplet energy level than the phosphorescent material.

4. A method according to claim 2 , wherein the conductive organic material comprises poly (ethylenedioxythiophene).

5. A method according to claim 1 wherein the first charge transporting material comprises a cross-linkable material and the rendering comprises subjecting the first charge transporting layer to heat or electromagnetic radiation in order to cross-link the first charge transporting material.

6. A method according to claim 1 wherein the first charge transporting material is a polymer.

7. A method according to claim 6 wherein the polymer comprises an optionally substituted triarylamine repeat unit.

8. A method according to claim 7 wherein the triarylamine repeat unit comprises an optionally substituted repeat unit of formula (I):

wherein each Ar 1 , Ar 2 and Ar 3 is the same or different and independently represents optionally substituted aryl; and n is 0 or 1.

9. A method according to claim 6 wherein the polymer comprises a repeat unit selected from optionally substituted fluorene, indenofluorene, spirofluorene and phenylene.

10. A method according to claim 1 wherein the phosphorescent material is a metal complex.

11. An organic light emitting diode obtainable by the method according to claim 1 .

Assignees

• Cambridge Display Tech Ltd

Inventors

• Patel Nalinkumar Lallubhai
• Conway Natasha M
• Leadbeater Mark
• Grizzi Ilaria

Classifications

• Y10S428/917

  Electroluminescent · CPC title

• H10K50/155

  comprising dopants · CPC title

• H10K71/12 Primary

  using liquid deposition, e.g. spin coating · CPC title

• H01L51/0059

  Electricity · mapped topic

• H01L51/5221

  Electricity · mapped topic