Organic light emitting diode, display panel and display device
Disclosed are an organic light emitting diode, a display panel and a display device. The organic light emitting diode includes a first electrode, a second electrode, a light emitting layer and an electron blocking layer, the first electrode and the second electrode are disposed opposite to each other, the light emitting layer is disposed between the first electrode and the second electrode, the electron blocking layer is disposed between the light emitting layer and the first electrode. A LUMO level of the electron blocking layer is higher than a LUMO level of a light emitting host material in the light emitting layer, a first level difference between the LUMO level of the electron blocking layer and the LUMO level of the light emitting host material in the light emitting layer is represented by A, where A≥0.4 eV.
1. An organic light emitting diode (OLED), comprising:
a first electrode;
a second electrode disposed oppositely to the first electrode;
a light emitting layer disposed between the first electrode and the second electrode;
an electron blocking layer disposed between the light emitting layer and the first electrodes; and
an intermediate doped layer, which is disposed between the light emitting layer and the electron blocking layer;
wherein a lowest unoccupied molecular orbital (LUMO) level of the electron blocking layer is higher than a LUMO level of a light emitting host material in the light emitting layer, a first level difference between the LUMO level of the electron blocking layer and the LUMO level of the light emitting host material in the light emitting layer is represented by A, and A≥0.4 eV;
wherein the intermediate doped layer comprises a light emitting host material and an electron blocking material, and the light emitting host material in the intermediate doped layer is the same as the light emitting host material in the light emitting layer;
the light emitting host material comprises at least one of 4,4-N,N-dicarbazole biphenyl, 9,10-dinaphthylanthracene, 4,4′,4″-N,N′,N″-tris(3-phenylcarbazole)aniline, 3,5-N,N′-dicarbazole benzene, or 4,4′-N,N′-dicarbazole-2,2′-dimethylbiphenyl; and
the electron blocking material comprises at least one of 4,4′-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] or 4,4′,4″-tris(carbazol-9-yl)triphenylamine.
2. The OLED of claim 1 , wherein a highest occupied molecular orbital (HOMO) level of the electron blocking layer is higher than a HOMO level of the light emitting host material in the light emitting layer, a second level difference between the HOMO level of the electron blocking layer and the HOMO level of the light emitting host material in the light emitting layer is represented by B, and B≤0.2 eV.
3. The OLED of claim 1 , wherein a thickness of the electron blocking layer is represented by C, and 3 nm≤C≤20 nm.
4. The OLED of claim 1 , wherein the electron blocking layer comprises aromatic amine derivative.
5. The OLED of claim 1 , wherein in the intermediate doped layer, a sum of a volume of the light emitting host material and a volume of the electron blocking material is represented by S, and the volume of the light emitting host material is represented by X, and a ratio of the volume of the light emitting host material to the volume of the electron blocking material satisfies 20%≤X/S≤80%.
6. The OLED of claim 5 , wherein the ratio of the volume of the light emitting host material to the volume of the electron blocking material is: X/S=50%.
7. The OLED of claim 1 , wherein a thickness of the intermediate doped layer is represented by E, and 0.1 nm≤E≤30 nm.
8. The OLED of claim 7 , wherein the thickness E of the intermediate doped layer is 5 nm, 10 nm or 20 nm.
9. The OLED of claim 1 , further comprising a first carrier function layer and a second carrier function layer;
the first carrier function layer is disposed between the light emitting layer and the second electrode, and the second carrier function layer is disposed between the first electrode and the electron blocking layer.
10. The OLED of claim 9 , wherein the first carrier function layer comprises an electron injection layer, an electron transport layer, and a hole blocking layer which are disposed in a stacked manner in a direction from the second electrode towards the light emitting layer;
the second carrier function layer comprises a hole injection layer and a hole transport layer which are disposed in a stacked manner in a direction from the first electrode towards the electron blocking layer.
11. A display panel, comprising a substrate and a plurality of pixel units, wherein the pixel units are disposed on one side of the substrate and arranged in an array;
wherein at least part of the plurality of pixel units comprises the organic light emitting diode of claim 1 .
12. A display device, comprising the display panel of claim 11 .