Display substrate, manufacturing method thereof and display device

A display substrate, comprising:

• a base substrate;
• a switch unit on the base substrate, wherein the switch unit comprises an output electrode, one side of the output electrode away from the base substrate is provided with a groove, and a depth of the groove is between 50 and 300 angstroms;
• a planarization layer on one side of the switch unit away from the base substrate, wherein a region, corresponding to the output electrode, of the planarization layer is provided with a planarization layer via hole, and an orthographic projection of the planarization layer via hole onto the base substrate is located within an orthographic projection region of the output electrode onto the base substrate;
• and
• a pixel electrode on one side of the planarization layer away from the switch unit, wherein the pixel electrode is in contact with a bottom surface of the groove through the planarization layer via hole,
• wherein the display substrate further comprises an insulating layer and a common electrode formed sequentially on one side of the pixel electrode away from the planarization layer,
• wherein the planarization layer is cured for less than or equal to 20 minutes,
• wherein the planarization layer is in direct contact with the switch unit, and the planarization layer is a single-layer structure,
• wherein a surface of a region exposed through the planarization layer via hole of the output electrode is etched through a wet etching process by using the planarization layer as a mask, to remove an oxidized portion formed on the surface of the region of the output electrode when curing the planarization layer.