# US 10,121,993 B2 · Frequency dependent light emitting devices

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- Number: US 10,121,993 B2
- Document ID: US10121993B2
- Status: Granted
- Kind: B2
- Application number: 15/904,569
- Filed: 2018-02-26
- Published: 2018-07-05
- Granted: 2018-11-06
- Earliest claimed: 2013-09-27
- Assignees: Wake Forest University
- Applicants: Wake Forest University
- Inventors: David Carroll; Robert Summers; Yonghua Chen
- Web page: https://patentgrep.com/patent/US10121993B2

## CPC

- H05B 44/00: Circuit arrangements for operating electroluminescent light sources (for operating light emitting diodes H05B45/00)
- H10H 20/062: {Light-emitting semiconductor devices having field effect type light-emitting regions, e.g. light-emitting High-Electron Mobility Transistors}
- H10H 20/824: comprising only Group III-V materials, e.g. GaP
- H10H 20/833: Transparent materials
- H10K 50/30: Organic light-emitting transistors
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 50/115: comprising active inorganic nanostructures, e.g. luminescent quantum dots
- H10K 50/85: Arrangements for extracting light from the devices
- H10K 71/841: {Applying alternating current [AC] during manufacturing or treatment}
- H10K 85/111: {comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene}
- H10K 85/1135: {Polyethylene dioxythiophene [PEDOT]; Derivatives thereof}
- H10K 85/115: {Polyfluorene; Derivatives thereof}
- H10K 85/151: {Copolymers}
- H10K 85/30: Coordination compounds
- H10K 2101/10: Triplet emission
- H10K 2101/27: {Combination of fluorescent and phosphorescent emission}
- H10K 2102/00: Constructional details relating to the organic devices covered by this subclass
- Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

An electroluminescent device described herein, in one aspect, comprises a first electrode and second electrode and a light emitting layer positioned between the first and second electrodes. A current injection gate is positioned between the first electrode and the light emitting layer or the second electrode and the light emitting layer. In some embodiments, the current injection gate comprises a semiconductor layer of electronic structure restricting injected current flow from the first or second electrode through the semiconductor layer as a function of alternating current voltage frequency applied to the first and second electrodes.

## Claims

### Claim 1

A method of preparing an electroluminescent device comprising:
depositing a first electrode layer on a substrate;
depositing a current injection gate layer on the first electrode layer, the current injection gate layer comprising a semiconductor layer of electronic structure restricting injected current flow as a function of alternating current voltage frequency;
depositing an organic light emitting layer on the current injection gate layer, the organic light emitting layer comprising a triplet emitter phase; and
depositing a second electrode layer on the organic light emitting layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first electrode, second electrode, or both the first electrode and the second electrode are radiation transmissive.

### Claim 3 (depends on 1)

The method of claim 1, wherein the organic light emitting layer further comprises a singlet emitter phase.

### Claim 4 (depends on 3)

The method of claim 3, wherein the singlet emitter phase comprises one or more conjugated polymers or oligomers, small molecules, or mixtures thereof.

### Claim 5 (depends on 3)

The method of claim 3, wherein the triplet emitter phase is dispersed in the singlet emitter phase.

### Claim 6 (depends on 5)

The method of claim 5, wherein the organic light emitting layer comprises a dielectric host for the singlet emitter phase and the triplet emitter phase.

### Claim 7 (depends on 1)

The method of claim 1, wherein the triplet emitter phase comprises a phosphorescent transition metal complex.

### Claim 8 (depends on 1)

The method of claim 1, wherein the organic light emitting layer further comprises a nanoparticle phase.

### Claim 9 (depends on 8)

The method of claim 8, wherein the nanoparticle phase comprises carbon nanoparticles, inorganic nanoparticles, or mixtures thereof.

### Claim 10 (depends on 9)

The method of claim 9, wherein the nanoparticle phase is dispersed uniformly throughout the organic light emitting layer, or heterogeneously distributed in the organic light emitting layer.

### Claim 11 (depends on 1)

The method of claim 1, wherein injected current flow through the semiconductor layer of the gate decreases with increasing frequency of the applied alternating current voltage.

### Claim 12 (depends on 1)

The method of claim 1, wherein the semiconductor layer is a composite layer comprising inorganic particles dispersed in a conjugated polymeric matrix.

### Claim 13 (depends on 1)

The method of claim 1, wherein the semiconductor layer is formed of an intrinsic semiconductor.

### Claim 14 (depends on 13)

The method of claim 13, wherein the intrinsic semiconductor is an inorganic semiconductor.

### Claim 15 (depends on 13)

The method of claim 13, wherein the intrinsic semiconductor is an organic semiconductor.

### Claim 16 (depends on 1)

The method of claim 1, wherein the semiconductor layer is formed of a material having a bandgap of at least 2 eV.

### Claim 17 (depends on 1)

The method of claim 1, further comprising:
depositing an electron dopant layer on a first side of the light emitting organic layer.

### Claim 18 (depends on 17)

The method of claim 17, further comprising:
depositing a hole dopant layer on an opposite second side of the light emitting organic layer.

### Claim 19 (depends on 1)

The method of claim 1, wherein the light emitting organic layer comprises an electron dopant and a hole dopant.

### Claim 20 (depends on 1)

The method of claim 1 having an efficiency of at least 100 lm W−1.