# US 10,319,931 B2 · Light emitting device, method for manufacturing light emitting device, and display device

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- Number: US 10,319,931 B2
- Document ID: US10319931B2
- Status: Granted
- Kind: B2
- Application number: 15/529,527
- Filed: 2016-06-03
- Published: 2018-07-05
- Granted: 2019-06-11
- Earliest claimed: 2016-03-23
- Assignees: Boe Technology Group Co., Ltd.
- Applicants: Boe Technology Group Co., Ltd.
- Inventors: Juanjuan You
- Web page: https://patentgrep.com/patent/US10319931B2

## CPC

- H10K 71/16: using physical vapour deposition [PVD], e.g. vacuum deposition or sputtering
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 50/12: comprising dopants
- H10K 50/13: comprising stacked EL layers within one EL unit
- H10K 50/15: Hole transporting layers
- H10K 50/181: {Electron blocking layers}
- H10K 2101/10: Triplet emission
- 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

A light emitting device includes: a first electrode, a second electrode and an electroluminescent layer (EL) interposed between the first electrode and the second electrode, the EL including an emitting material layer (EML) and an electron blocking layer (EBL), wherein the EML includes a first base material doped with a first guest material, and the EBL includes a second base material doped with a second guest material.

## Claims

### Claim 1

A light emitting device, comprising a first electrode, a second electrode and an electroluminescent layer (EL) interposed between the first electrode and the second electrode, the EL comprising an emitting material layer (EML) and an electron blocking layer (EBL), wherein:
the EML comprises a first base material doped with a first guest material,
the EBL comprises a second base material doped with a second guest material, and
wherein the first guest material and the second guest material are both light emitting materials, and
wherein light emitted by the first guest material has a dark blue color, and light emitted by the second guest material has a light blue color.

### Claim 2 (depends on 1)

The light emitting device according to claim 1, wherein the first guest material has an energy band width larger than an energy band width of the second guest material.

### Claim 3 (depends on 1)

The light emitting device according to claim 1, wherein the second base material has a triplet level higher than a triplet level of the first guest material, and the triplet level of the second base material is higher than a triplet level of the first base material.

### Claim 4 (depends on 1)

The light emitting device according to claim 1, wherein the EL further comprises a hole transport layer (HTL) interposed between the first electrode and the EBL; and
the HTL has a highest occupied molecular orbit (HOMO) energy higher than a HOMO energy of the EBL, and the HOMO energy of the EBL is higher than a HOMO energy of the EML.

### Claim 5 (depends on 4)

The light emitting device according to claim 4, wherein a difference between the HOMO energy of the EBL and the HOMO energy of the HTL is equal to or smaller than 0.4 eV, and a difference between the HOMO energy of the EML and the HOMO energy of the EBL is equal to or smaller than 0.4 eV.

### Claim 6 (depends on 1)

The light emitting device according to claim 1, wherein the second guest material has a dopant concentration of 1% to 5%.

### Claim 7 (depends on 6)

The light emitting device according to claim 6, wherein the dopant concentration of the second guest material is 3%.

### Claim 8 (depends on 1)

The light emitting device according to claim 1, wherein the EBL has a thickness between 5 nm to 20 nm.

### Claim 9 (depends on 8)

The light emitting device according to claim 8, wherein the thickness of the EBL is between 10 nm to 15 nm.

### Claim 10 (depends on 1)

The light emitting device according to claim 1, wherein the light emitting device is a blue light emitting device.

### Claim 11

A display device comprising a light emitting device, wherein the light emitting device comprises a first electrode, a second electrode and an electroluminescent layer (EL) interposed between the first electrode and the second electrode, the EL comprising an emitting material layer (EML) and an electron blocking layer (EBL), wherein:
the EML comprises a first base material doped with a first guest material,
the EBL comprises a second base material doped with a second guest material, and
wherein the first guest material and the second guest material are both light emitting materials, and
wherein light emitted by the first guest material has a dark blue color, and light emitted by the second guest material has a light blue color.

### Claim 12 (depends on 11)

The display device according to claim 11, wherein the first guest material has an energy band width larger than an energy band width of the second guest material.

### Claim 13 (depends on 11)

The display device according to claim 11, wherein the second base material has a triplet level higher than a triplet level of the first guest material, and the triplet level of the second base material is higher than a triplet of the first base material.

### Claim 14 (depends on 11)

The display device according to claim 11, wherein the EL further comprises a hole transport layer (HTL) interposed between the first electrode and the EBL; and
the HTL has a highest occupied molecular orbit (HOMO) energy higher than a HOMO energy of the EBL, and the HOMO energy of the EBL is higher than a HOMO energy of the EML.

### Claim 15 (depends on 14)

The display device according to claim 14, wherein a difference between the HOMO energy of the EBL and that the HOMO energy of the HTL is equal to or smaller than 0.4 eV, and a difference between the HOMO energy of the EML and that the HOMO energy of the EBL is equal to or smaller than 0.4 eV.

### Claim 16 (depends on 11)

The display device according to claim 11, wherein the light emitting device is a blue light emitting device.

### Claim 17

A method for manufacturing a light emitting device, comprising:
forming an electroluminescent layer (EL) comprising an emitting material layer (EML) and an electron blocking layer (EBL) on a first electrode, the EML comprising a first base material doped with a first guest material and the EBL comprising a second base material doped with a second guest material; and
forming a second electrode on the EL,
wherein the first guest material and the second guest material are both light emitting materials, and wherein light emitted by the first guest material has a dark blue color, and light emitted by the second guest material has a light blue color.

### Claim 18 (depends on 17)

The method according to claim 17, wherein the step of forming the EL on the first electrode comprising:
forming the EBL by evaporating the second base material at a first set evaporating rate and the second guest material at a second set evaporating rate on the first electrode; and
forming the EL by evaporating the first base material at a third set evaporating rate and the first guest material at a fourth set evaporating rate on the EBL.