# US 12,604,599 B2 · Display panel with improved charge generation layer

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- Number: US 12,604,599 B2
- Document ID: US12604599B2
- Status: Granted
- Kind: B2
- Application number: 18/050,832
- Filed: 2022-10-28
- Published: 2024-03-28
- Granted: 2026-04-14
- Earliest claimed: 2022-09-28
- Assignees: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Applicants: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Inventors: Shuren Zhang
- Web page: https://patentgrep.com/patent/US12604599B2

## CPC

- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 59/32: Stacked devices having two or more layers, each emitting at different wavelengths
- H10K 71/00: Manufacture or treatment specially adapted for the organic devices covered by this subclass
- H10K 71/13: using printing techniques, e.g. ink-jet printing or screen printing
- 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

The present invention relates to a display panel and a manufacturing method of the display panel. A charge generation layer of the present invention is produced using a mixture of an n-type organic material, a p-type organic material, and a polar solvent. The n-type organic material and the p-type organic material are mixed to form the charge generation layer, so that a contact area between the n-type organic material and the p-type organic material is increased. Accordingly, the present invention improves the transfer efficiency of charges, improves chances of separation of electrons and holes, and finally improves the charge generation efficiency of the charge generation layer. Therefore, the present invention avoids the use of a fine metal mask (FMM) in an evaporation process. Consequently, the present application reduces production costs and can be used in large-size-screen G8.6 production lines.

## Claims

### Claim 1

A display panel, comprising:
a substrate;
a first electrode disposed on the substrate;
a charge generation layer disposed at one side of the first electrode away from the substrate; and
a second electrode disposed at one side of the charge generation layer away from the substrate;
wherein a material of the charge generation layer comprises a mixture of an n-type organic material and a p-type organic material, and
an energy level difference between a highest occupied molecular orbital (HOMO) energy level of the p-type organic material and a lowest unoccupied molecular orbital (LUMO) energy level of the n-type organic material is less than 2 eV.

### Claim 2 (depends on 1)

The display panel according to claim 1, wherein the HOMO energy level of the p-type organic material ranges from 4.5 eV to 5.5 eV.

### Claim 3 (depends on 1)

The display panel according to claim 1, wherein the LUMO energy level of the n-type organic material ranges from 2 eV to 4 eV.

### Claim 4 (depends on 1)

The display panel according to claim 1, wherein a mass ratio of the n-type organic material to the p-type organic material is 1:0.1 to 1:9.

### Claim 5 (depends on 1)

The display panel according to claim 1, wherein the n-type organic material is a metal chelate compound, the p-type organic material is a triarylamine-based derivative, and the polar solvent comprises an aromatic-alcohol-based derivative.

### Claim 6 (depends on 5)

The display panel according to claim 5, wherein the metal chelate compound comprises: one or more than one of 8-hydroxyquinolate aluminum, a derivative of 8-hydroxyquinolate aluminum, 8-hydroxyquinolate lithium, or a derivative of 8-hydroxyquinolate lithium.

### Claim 7 (depends on 1)

The display panel according to claim 1, wherein a thickness of the charge generation layer ranges from 10 nm to 60 nm.

### Claim 8 (depends on 1)

The display panel according to claim 1, further comprising:
a first functional layer disposed between the first electrode and the charge generation layer;
a first light-emitting layer disposed between the first functional layer and the charge generation layer;
a second functional layer disposed between the charge generation layer and the second electrode;
a second light-emitting layer disposed between the second functional layer and the second electrode; and
a third functional layer disposed between the second light-emitting layer and the second electrode.