Display substrate, method of manufacturing thereof and display device

A display substrate, comprising:

• a base, and a pixel defining layer and sub-pixels on the base,
• wherein the pixel defining layer comprises first defining portions along a first direction and second defining portions along a second direction, wherein the first direction intersects the second direction;
• a distance from a surface of one of the first defining portions away from the base to the base are greater than a distance from a surface of one of the second defining portions away from the base to the base;
• by the first defining portions and the second defining portions, a plurality of pixel openings that define light-emitting regions of the sub-pixels are formed;
• one of the sub-pixels comprises a light-emitting device, and the light-emitting device comprises an anode layer, a hole injection layer, a hole transport layer, a light-emitting material layer, an electron transport layer, an electron injection layer and a cathode layer that are arranged sequentially;
• the hole injection layer, the hole transport layer, and the light-emitting material layer of the one of the sub-pixels are located between two adjacent first defining portions;
• hole injection layers of the sub-pixels between the two adjacent first defining portions are connected with each other;
• hole transport layers of the sub-pixels located between the two adjacent first defining portions are connected with each other;
• light-emitting material layers of the sub-pixels located between the two adjacent first defining portions are connected with each other;
• the light-emitting device comprises at least one electron injection layer, and the light-emitting device further comprises at least one high impedance layer between the electron injection layer and the cathode layer;
• for one of the at least one electron injection layer, the high impedance layer comprises a first high impedance film layer, a second high impedance film layer between the first high impedance film layer and the cathode layer, and a third high impedance film layer located between the first high impedance film layer and the electron injection layer;
• a resistivity of the first high impedance film layer is respectively higher than a resistivity of the second high impedance film layer and a resistivity of the third high impedance film layer;
• the resistivity of the first high impedance film layer, the resistivity of the second high impedance film layer, and the resistivity of the third high impedance film layer are respectively higher than a resistivity of the cathode layer and a resistivity of the electron injection layer.

A method of manufacturing a display substrate, comprising:

• providing a base;
• forming a light-emitting device located on the base;
• wherein forming the light-emitting device located on the base comprises:
• sequentially forming an anode layer, a light-emitting material layer, an electron transport layer, an electron injection layer, a high impedance layer and a cathode layer;
• the light-emitting device comprises at least one electron injection layer and at least one high impedance layer, the at least one high impedance layer is located between the electron injection layer and the cathode layer;
• forming one of the at least one high impedance layer comprises:
• sequentially forming a third high impedance film layer, a first high impedance film layer located on a side of the third high impedance film layer away from the anode layer, and a second high impedance film layer located on a side of the first high impedance film layer away from the anode layer;
• wherein a resistivity of the first high impedance film layer is respectively higher than a resistivity of the second high impedance film layer and a resistivity of the third high impedance film layer;
• the resistivity of the first high impedance film layer, the resistivity of the second high impedance film layer, and the resistivity of the third high impedance film layer are respectively higher than a resistivity of the cathode layer and a resistivity of the electron injection layer;
• wherein a thickness of the first high impedance film layer is respectively larger than a thickness of the second high impedance film layer and a thickness of the third high impedance film layer.