Display substrate, method for manufacturing display substrate, and display apparatus

1. A display substrate, comprising:

a base substrate;

a plurality of first electrodes arranged in an array on the base substrate; and

a pixel defining layer defining a plurality of openings on the base substrate; the plurality of openings overlapping the plurality of first electrodes respectively;

wherein the pixel defining layer comprises a plurality of first pixel defining units and a plurality of second pixel defining units, and the plurality of second pixel defining units are disposed on the plurality of first pixel defining units;

the plurality of first pixel defining units are separated from one another; and

orthographic projections of the plurality of first pixel defining units on the base substrate fall within orthographic projections of the plurality of first electrodes on the base substrate respectively, and the plurality of second pixel defining units cover sidewalls of the plurality of first electrodes and separate adjacent first electrodes.

2. The display substrate of claim 1 , wherein one of the plurality of first pixel defining units has a hydrophilic side surface;

one of the plurality of second pixel defining units has a hydrophobic side surface;

the hydrophilic side surface and the hydrophobic side surface face a same opening, and the hydrophilic side surface is between the base substrate and the hydrophobic side surface.

3. The display substrate of claim 1 , wherein the plurality of first pixel defining units are separated from one another by the plurality of second pixel defining units.

4. The display substrate of claim 1 , wherein orthographic projection of one of the plurality of first pixel defining units on the base substrate encloses a first opening area.

5. The display substrate of claim 1 , wherein the plurality of second pixel defining units are directly in contact with one another.

6. The display substrate of claim 4 , wherein orthographic projection of one of the plurality of second pixel defining units on the base substrate encloses a second opening area.

7. The display substrate of claim 6 , wherein an area of the first opening area is smaller than or substantially equal to an area of the second opening area.

8. The display substrate of claim 1 , wherein the plurality of first pixel defining units comprises a hydrophilic material and the plurality of second pixel defining units comprises a hydrophobic material.

9. The display substrate of claim 1 , wherein a maximum distance from a point on the hydrophilic side surface to the first electrode is in a range of about 0.5 μm to about 2 μm.

10. The display substrate of claim 1 , wherein a maximum distance from a point on the hydrophobic side surface to the first electrode is in a range of about 0.6 μm to about 4 μm.

11. A method for manufacturing a display substrate, comprising:

forming a plurality of first pixel defining layer sub-films on a plurality of first electrodes respectively on a base substrate by a patterning process, the plurality of first electrodes being arranged in an array;

forming a plurality of first pixel defining layer units and a plurality of second pixel defining layer units,

wherein the plurality of first pixel defining layer units are separate from one another;

wherein forming the plurality of first pixel defining layer sub-films on the plurality of first electrodes respectively on the base substrate by a patterning process comprises:

forming a first electrode film on the base substrate;

forming a first pixel defining layer film on the first electrode film;

patterning the first electrode film and the first pixel defining layer film to form the plurality of first pixel defining layer sub-films on the plurality of first electrodes respectively on the base substrate with a first mask; and

wherein orthographic projections of the plurality of first pixel defining layer units on the base substrate fall within orthographic projections of the plurality of first electrodes on the base substrate respectively, and the plurality of second pixel defining layer units cover sidewalls of the plurality of first electrodes and separate adjacent first electrodes.

12. The method of claim 11 , wherein forming the plurality of first pixel defining layer units and the plurality of second pixel defining layer units comprises:

forming a second pixel defining layer film covering the plurality of first pixel defining layer sub-films;

patterning the second pixel defining layer film and the plurality of first pixel defining layer sub-films with a second mask to form the plurality of first pixel defining layer units and the plurality of second pixel defining layer units,

wherein at least one of the plurality of first pixel defining layer units comprises a hydrophilic side surface, and at least one of the plurality of second pixel defining layer units comprises a hydrophobic side surface.

13. The method of claim 11 , wherein, forming the plurality of first pixel defining layer units and the plurality of second pixel defining layer units comprises:

forming a second pixel defining layer film;

patterning the second pixel defining layer film and the plurality of first pixel defining layer sub-films with two different masks to form the plurality of first pixel defining layer units and the plurality of second pixel defining layer units,

wherein at least one of the plurality of first pixel defining layer units comprises a hydrophilic side surface, and at least one of the plurality of second pixel defining layer units comprises a hydrophobic side surface.

14. The method of claim 11 , wherein the plurality of first pixel defining layer units and the plurality of second pixel defining layer units define a plurality of openings; the plurality of openings overlap the plurality of first electrodes respectively.

15. The method of claim 14 , further comprising:

forming an organic emitting solution in the plurality of openings so that the organic emitting solution is in contact with both the hydrophilic side surface and the hydrophobic side surface;

drying the organic emitting solution to form an organic emitting layer.

16. A display apparatus, comprising:

the display substrate of claim 1 ;

an organic emitting layer in at least one of the plurality of openings; and

a second electrode on the organic emitting layer.

17. The display apparatus of claim 16 , wherein a thickness of the organic emitting layer is smaller than or substantially the same as the maximum vertical distance from the point on the hydrophilic side surface to the first electrode.