# US 10,483,474 B2 · Organic light-emitting device with electron blocking layer and trapping layer and organic light-emitting display using the same

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- Number: US 10,483,474 B2
- Document ID: US10483474B2
- Status: Granted
- Kind: B2
- Application number: 15/661,233
- Filed: 2017-07-27
- Published: 2018-02-01
- Granted: 2019-11-19
- Earliest claimed: 2016-07-29
- Assignees: LG Display Co., Ltd.
- Applicants: LG Display Co., Ltd.
- Inventors: Bo-Seong Kim
- Web page: https://patentgrep.com/patent/US10483474B2

## CPC

- H10K 50/181: {Electron blocking layers}
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 50/15: Hole transporting layers
- H10K 59/12: Active-matrix OLED [AMOLED] displays
- H10K 85/6572: {comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole}
- H10K 2101/30: Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
- H10K 2101/40: Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

An organic light-emitting device includes: an anode, a hole transport layer over the anode, an electron blocking layer over the hole transport layer, an organic emitting layer contacting the electron blocking layer, an electron transport layer contacting the organic emitting layer, a cathode over the electron transport layer, and a trapping layer between the hole transport layer and the electron blocking layer, wherein a LUMO energy level of the trapping layer: differs from a HOMO energy level of the electron blocking layer within a range of 1 eV, or is equal to the HOMO energy level of the electron blocking layer.

## Claims

### Claim 1

An organic light-emitting device, comprising:
an anode;
a hole transport layer over the anode;
an electron blocking layer over the hole transport layer;
an organic emitting layer contacting the electron blocking layer;
an electron transport layer contacting the organic emitting layer;
a cathode over the electron transport layer; and
a trapping layer between the hole transport layer and the electron blocking layer,
wherein the trapping layer contacts the hole transport layer and the electron blocking layer at opposite surfaces,
wherein a LUMO energy level of the trapping layer differs from a HOMO energy level of the electron blocking layer within a range of 1 eV,
wherein the LUMO energy level of the trapping layer differs from a HOMO energy level of the hole transport layer within a range of 1 eV, and
wherein the LUMO energy level of the trapping layer is between the HOMO energy level of the hole transport layer and the electron blocking layer.

### Claim 2 (depends on 1)

The organic light-emitting device according to claim 1, wherein the LUMO energy level of the trapping layer is lower than the HOMO energy level of the electron blocking layer.

### Claim 3 (depends on 1)

The organic light-emitting device according to claim 1,
wherein the HOMO energy level of the electron blocking layer is higher than a HOMO energy level of the organic emitting layer by 0.4 eV.

### Claim 4 (depends on 1)

The organic light-emitting device according to claim 1, wherein a thickness of the trapping layer is less than or equal to ⅕ times of a thickness of hole transport layer.

### Claim 5 (depends on 4)

The organic light-emitting device according to claim 4, wherein the thickness of the trapping layer is about 5 Å to 10 Å.

### Claim 6 (depends on 1)

The organic light-emitting device according to claim 1, wherein electrons that have escaped from the electron blocking layer toward the hole transport layer are captured by the trapping layer when voltages are applied to the anode and the cathode.

### Claim 7 (depends on 1)

The organic light-emitting device according to claim 1, wherein a LUMO energy level of the electron blocking layer is higher than a LUMO energy level of the organic emitting layer.

### Claim 8

An organic light-emitting display, comprising:
a substrate comprising a plurality of subpixels;
a thin-film transistor in each subpixel over the substrate; and
an organic light-emitting element at each sub-pixel, the organic light-emitting element comprising:
an anode;
a hole transport layer over the anode;
an electron blocking layer over the hole transport layer;
an organic emitting layer contacting the electron blocking layer;
an electron transport layer contacting the organic emitting layer;
a cathode over the electron transport layer; and
a trapping layer between the hole transport layer and the electron blocking layer,
wherein each thin-film transistor is connected to one of: the anode and the cathode, and
wherein a LUMO energy level of the trapping layer differs from a HOMO energy level of the electron blocking layer within a range of 1 eV,
wherein the LUMO energy level of the trapping layer differs from a HOMO energy level of the hole transport layer within a range of 1 eV, and
wherein the LUMO energy level of the trapping layer is between the HOMO energy level of the hole transport layer and the electron blocking layer.

### Claim 9 (depends on 8)

The organic light-emitting display according to claim 8, wherein the LUMO energy level of the trapping layer is lower than the HOMO energy level of the electron blocking layer.

### Claim 10 (depends on 8)

The organic light-emitting display according to claim 8, wherein the HOMO energy level of the electron blocking layer is higher than a HOMO energy level of the organic emitting layer by 0.4 eV.

### Claim 11 (depends on 8)

The organic light-emitting display according to claim 8, wherein a thickness of the trapping layer is less than or equal to ⅕ times of a thickness of hole transport layer.

### Claim 12 (depends on 8)

The organic light-emitting display according to claim 8, wherein a LUMO energy level of the electron blocking layer is higher than a LUMO energy level of the organic emitting layer.