Organic Light-Emitting Diode, Display Panel and Display Device

1 . An organic light-emitting diode, comprising an anode, a cathode, at least two light emitting layers arranged between the anode and the cathode, and a hole transport element and an electron transport element which are arranged between two adjacent light emitting layers and arranged in sequence along a direction far away from the cathode, wherein:

the hole transport element comprises at least two hole transport layers, wherein each of the hole transport layers comprises a hole transport material and a P-type material doped in the hole transport material, and a volume concentration of the P-type material of a hole transport layer adjacent to the light emitting layer is less than a volume concentration of the P-type material of a hole transport layer adjacent to the electron transport element; and

wherein the electron transport element comprises at least two electron transport layers, wherein the electron transport layer comprises an electron transport material and an N-type material doped in the electron transport material, and a volume concentration of the N-type material of an electron transport layer adjacent to the light emitting layer is less than a volume concentration of the N-type material of an electron transport layer adjacent to the hole transport element.

2 . The organic light-emitting diode of claim 1 , wherein the volume concentrations of the P-type materials of the at least two hole transport layers increase in sequence along the direction far away from the cathode; and

the volume concentrations of the N-type materials of the at least two hole transport layers increase in sequence along a direction far away from the anode.

3 . The organic light-emitting diode of claim 1 , wherein a thickness of the hole transport layer, adjacent to the light emitting layer, in the at least two hole transport layers is greater than a thickness of remaining hole transport layers; and

a thickness of the electron transport layer, adjacent to the light emitting layer, in the at least two electron transport layers is greater than a thickness of remaining electron transport layers.

4 . The organic light-emitting diode of claim 1 , wherein the hole transport element comprises two hole transport layers, which are respectively a first hole transport layer and a second hole transport layer along the direction far away from the cathode; and

the electron transport element comprises two electron transport layers, which are respectively a first electron transport layer and a second electron transport layer along a direction far away from the anode.

5 . The organic light-emitting diode of claim 4 , wherein a thickness of the first hole transport layer is 10 nm˜120 nm, and a thickness of the second hole transport layer is 5 nm˜20 nm.

6 . The organic light-emitting diode of claim 4 , wherein a volume concentration of the P-type material of the first hole transport layer is 0.05%˜10%, and a volume concentration of the P-type material of the second hole transport layer is 1%˜30%.

7 . The organic light-emitting diode of claim 4 , wherein a thickness of the first electron transport layer is 20 nm˜60 nm, and a thickness of the second electron transport layer is 5 nm˜20 nm.

8 . The organic light-emitting diode of claim 4 , wherein a volume concentration of the N-type material of the first electron transport layer is 0.1%˜5%, and a volume concentration of the N-type material of the second electron transport layer is 1%˜30%.

9 . The organic light-emitting diode of claim 1 , wherein the N-type material comprises an alkali metal, an alkaline-earth metal or a rare-earth metal.

10 . The organic light-emitting diode of claim 1 , wherein the P-type material comprises an inorganic material, and the inorganic material comprises MoO 3 .

11 . The organic light-emitting diode of claim 1 , wherein the P-type material comprises an organic material, and the organic material comprises:

wherein R 1 to R 21 are independently selected from hydrogen atoms, deuterium atoms, alkyl, alkoxy, substituted or unsubstituted aryl; X 1 , X 2 and X 3 are independently selected from substituted or unsubstituted aryl, and a substituent in the substituted or unsubstituted aryl at least comprises one electron acceptor group.

12 . The organic light-emitting diode of claim 1 , wherein the hole transport material comprises an aromatic amine material or a carbazole material.

13 . The organic light-emitting diode of claim 1 , wherein the electron transport material comprises a biphenyl material, a pyridine material, a benzoylpyridine material or a phenanthroline material.

14 . A display panel, comprising an organic light-emitting diode, wherein the organic light-emitting diode comprises:

an anode, a cathode, at least two light emitting layers arranged between the anode and the cathode, and a hole transport element and an electron transport element which are arranged between two adjacent light emitting layers and arranged in sequence along a direction far away from the cathode, wherein:

the hole transport element comprises at least two hole transport layers, wherein each of the hole transport layers comprises a hole transport material and a P-type material doped in the hole transport material, and a volume concentration of the P-type material of a hole transport layer adjacent to the light emitting layer is less than a volume concentration of the P-type material of a hole transport layer adjacent to the electron transport element; and

wherein the electron transport element comprises at least two electron transport layers, wherein the electron transport layer comprises an electron transport material and an N-type material doped in the electron transport material, and a volume concentration of the N-type material of an electron transport layer adjacent to the light emitting layer is less than a volume concentration of the N-type material of an electron transport layer adjacent to the hole transport element.

15 . A display device, comprising the display panel of claim 14 .