Method for producing a high efficiency organic light emitting device having a transparent composite electrode comprising a film of conductive nanowires, carbon nanoparticles, light scattering nanoparticles, and a polymer support

Patent metadata

Field	Value
Publication number	US-9490454-B2
Application number	US-201514600194-A
Country	US
Kind code	B2
Filing date	Jan 20, 2015
Priority date	Jul 20, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A method for producing high efficiency organic light emitting devices, that have an organic semiconductor active layer sandwiched between electrodes where at least one of the electrodes is a film of conductive nanowires, carbon nanoparticles, light scattering nanoparticles and a polymer support. The light scattering nanoparticles can be incorporated in the conductive nanowires, carbon nanoparticle or polymer support elements of the electrode. The second electrode can be identical to the first to provide a symmetrical device or can be a conductive paste or metal layer. The entire process, including the formation of both of the electrodes, the emissive polymer layer, and the substrate, may be carried out by solution processing.

First claim

I claim:

1. An organic light emitting device, comprising:
a transparent composite electrode comprising metal wires, carbon particles, light scattering particles, and a polymer support, wherein:
the carbon particles comprise at least one particle selected from a carbon nanotube, graphite powder, and graphene,
the metal wires are applied to the carbon particles to form a porous bilayer,
the polymer support comprises a polymer matrix, the polymer matrix containing the light scattering particles and the polymer matrix coupled to the porous bilayer to form a composite film;

at least one semiconductive active layer electrically coupled to the transparent electrode; and
a second electrode electrically coupled to the active layer, wherein the organic light emitting device is fabricated using a process comprising:
depositing the carbon particles on a surface of a platform to form a carbon layer;
applying the metal wires to the carbon layer to form a porous bilayer;
coupling the porous bilayer to the polymer matrix containing the light scattering particles to form the composite film;
removing the composite film from the platform, wherein the surface of the composite film that is removed from the surface of the platform is smooth with average surface height variations of 20 nm or less;
applying the at least one semiconductive active layer to the carbon layer; and
depositing the second electrode on the active layer.

2. A device as recited claim 1 , wherein said light scattering particles comprise nanoparticles of BaSrTiO 3 .

3. A device as recited claim 1 , wherein the active layer comprises a hole transport material, an emissive material and an electron transport material.

4. A device as recited claim 3 , wherein said hole transport material comprises PEDOT:PSS, and the emissive material comprises a phosphorescent organometallic compound dispersed in a conjugated organic material.

5. A device as recited claim 1 , wherein the active layer comprises a plurality of organic semiconductor layers and a phosphorescent dopant dispersed in one of the organic semiconductor layers.

6. A device as recited in claim 1 , wherein the active layer comprises a layer of a conjugated polymer and an ionic species.

7. A device as recited in claim 1 , wherein said second electrode comprises a paste of conductive particles.

8. A method for producing an organic light emitting device, comprising:
depositing a plurality of carbon particles on a surface of a platform to form a carbon layer;
applying a plurality of conductive particles to the carbon layer to form a porous bilayer;
coupling the porous bilayer to a polymer matrix containing light scattering particles to form a composite film;
removing the composite film from the platform;
applying at least one semiconductive active layer to the carbon layer, wherein the composite film comprises a first electrode for injecting charge into the semiconductive active layer; and
depositing a second electrode on the semiconductive active layer.

9. A method as recited in claim 8 , wherein said coupling of the porous bilayer to the polymer matrix comprises:
coating the porous bilayer with at least one coating of monomers, wherein at least one coating comprises light scattering particles dispersed in the monomer; and
curing the monomers in situ to form the composite film.

10. A method as recited in claim 8 , wherein the surface of the composite film that is removed from the surface of the platform is smooth with average surface height variations of 20 nm or less.

11. A method as recited in claim 8 , wherein the polymer matrix contains a light transducing additive that absorbs light at one wavelength and re-emits light at a longer wavelength.

12. A method as recited in claim 8 , wherein the polymer matrix contains dispersed light scattering paricles of BaSrTiO 3 .

13. A method as recited in claim 12 , wherein the BaSrTiO 3 particles comprise 0.1 wt % to 1.0 wt % of the composite film.

14. A method as recited in claim 8 , wherein the composite film has a conductive surface with sheet resistance lower than 50 Ohm/square.

15. The method of claim 8 , wherein:
the carbon particles comprise at least one particle selected from a carbon nanotube, graphite powder, and graphene, and
the conductive particles comprise at least one metal chosen from silver, copper, gold, stainless steel, and nickel.

16. The method of claim 15 , wherein:
the carbon particles are cast using a solvent on the platform comprising glass, a silicon wafer, a polymer sheet, or metal in a planar sheet or drum,
the conductive particles are cast using a solvent on the carbon layer, the metal wires providing a percolation network for electrical conduction, and the carbon particles covering gaps in between the metal wires.

17. A method for producing an organic light emitting device, comprising:
depositing a plurality of carbon particles on a surface of a platform, the carbon particles comprising at least one particle chosen from a carbon nanotube, graphite powder, and graphene;
depositing a plurality of conductive particles on the deposited carbon particles to form a porous conductive layer, the conductive particles comprising at least one wire chosen from a metal wire, a conducting polymer wire, and a ceramic conductor wire;
incorporating light-scattering particles with either the carbon particles or the conductive particles;
coating the porous conductive layer with at least one coating of monomers;
polymerizing the applied monomers to form a conductive layer-polymer composite film;
removing the composite film from the platform;
applying a plurality of semiconducting active layers to a conductive layer surface of the composite film, wherein the composite film comprises a first electrode for injecting charge into the semiconducting active layer; and
coupling a second electrode to the semiconductive active layers.

18. A method as recited in claim 17 , wherein the surface of the composite film that is removed from the surface of the platform is smooth with surface height variations of 20 nm or less.

19. A method as recited in claim 17 , wherein the light-scattering nanoparticles comprise BaSrTiO 3 particles at 0.1 wt % to 1.0 wt % of the composite film.

20. The method of claim 17 , wherein:
the conductive particles comprise at least one metal chosen from silver, copper, gold, stainless steel, and nickel,
the carbon particles are cast using a solvent on the platform comprising glass, a silicon wafer, a polymer sheet, or metal in a planar sheet or drum, and
the conductive particles are cast using a solvent on the carbon layer, the metal wires providing a percolation network for electrical conduction, and the carbon particles covering gaps in between the metal wires.

Assignees

• Univ California

Inventors

• Pei Qibing

Classifications

• H10K59/877

  comprising scattering means · CPC title

• H10K59/80517

  Multilayers, e.g. transparent multilayers · CPC title

• B82Y10/00 Primary

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title

• H01L51/5206

  Electricity · mapped topic

• H01L51/5012

  Electricity · mapped topic