Organic electroluminescent display panel, manufacturing method thereof, and display device
The present disclosure relates to an organic electroluminescent display panel, a method of manufacturing the same, and a display device that can alleviate or avoid the occurrence of pixel crosstalk problems due to lateral conduction of the charge generation layer. An organic electroluminescent display panel is provided which comprises: a substrate; an anode layer and a pixel defining layer over the substrate, the pixel defining layer defining pixel units, wherein a recess is provided in the pixel defining layer between adjacent pixel units; a stack of organic electroluminescent units over the anode layer and the pixel defining layer, the stack comprising at least two organic electroluminescent units and a charge generation layer disposed between organic electroluminescent units which are adjacent to each other; a cathode layer over the stack, wherein the corresponding charge generation layers of the adjacent pixel units are disconnected at the recesses, and wherein the cathode layer is continuous at the recess.
1. A method of manufacturing an organic electroluminescent display panel, comprising:
forming over a substrate an anode layer for pixel units and a pixel defining layer for defining the pixel units, wherein a recess is provided in the pixel defining layer between adjacent pixel units, the recess having two opposite sidewalls each of which has a first portion and a second portion protruding from the first portion towards the other sidewall;
forming a stack of organic electroluminescent units over the anode layer and the pixel defining layer, the stack comprising at least two organic electroluminescent units and a charge generation layer between adjacent organic electroluminescent units, wherein corresponding discharge generation layers of adjacent pixel units are disconnected at the recess; and
forming a cathode layer over the substrate over which the stack is formed, wherein the cathode layer is continuous at the recess.
2. The method according to claim 1 , wherein in each of the pixel units, the stack comprises N organic electroluminescent units, and N is an integer ≥2, and
wherein forming over the substrate the anode layer for the pixel units and the pixel defining layer for defining the pixel units comprises:
forming the anode layer for the pixel units over the substrate;
forming a position-occupying layer at a position on the substrate corresponding to the recess to be formed, wherein a height of the position-occupying layer is set to be larger than a sum of the thicknesses of (N−1) organic electroluminescent units and all of the charge generation layers to be formed over the anode layer, and less than a sum of the thickness of the N organic electroluminescent units to be formed, the thickness of all of the charge generation layers, and the thickness of the cathode layer;
forming a pixel defining layer for defining pixel units, the pixel defining layer including an opening on the position-occupying layer, the opening exposing a part of the position-occupying layer; and
removing the position-occupying layer to form the recess in the pixel defining layer.
3. The method according to claim 2 , wherein
forming the position-occupying layer comprises forming the position-occupying layer with SiO 2 material;
removing the position-occupying layer comprises dry etching the position-occupying layer with CF 4 to remove the position-occupying layer.
4. The method according to claim 2 , wherein
forming the position-occupying layer comprises forming the position-occupying layer with a metal material;
removing the position-occupying layer comprises: wet etching the position-occupying layer with a metal etching solution to remove the position-occupying layer; and
the method further comprising: before removing the position-occupying layer, crystallizing the anode layer.
5. The method according to claim 2 , wherein
forming the position-occupying layer comprises forming the position-occupying layer with a positive photoresist material;
forming the pixel defining layer comprises forming the pixel defining layer with a negative photoresist material; and
removing the position-occupying layer comprises:
exposing the position-occupying layer formed with the positive photoresist material while exposing the pixel defining layer formed with the negative photoresist material; and
stripping the exposed position-occupying layer off using a positive photoresist stripping solution.
6. The method according to claim 1 , wherein the organic electroluminescence unit comprises:
a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer which are sequentially formed in a direction from the anode layer side to the cathode layer side.
7. The method according to claim 1 , wherein the organic electroluminescence unit is formed by evaporation using an open mask.
8. The method according to claim 1 , wherein the charge generation layer is formed by evaporation using an open mask.
9. The method according to claim 1 , wherein the cathode layer is formed by evaporation using an open mask.
10. The method according to claim 1 , wherein the recess penetrates the pixel defining layer in a thickness direction of the pixel defining layer.
11. The method according to claim 2 , wherein a distance between a projection, on the substrate, of an end of the second portion which is adjacent to the other sidewall and a projection, on the substrate, of an intersection line of the first portion with the bottom of the corresponding recess is 0.1-5 μm.