Display substrate and method for preparing the same, and display device

A display substrate, comprising a substrate and a plurality of pixel units on the substrate, at least one of the plurality of pixel units comprising a light-emitting unit, a photosensitive unit for detecting light emitted by the light-emitting unit, and an interlayer insulating layer between the photosensitive unit and the light-emitting unit,

• wherein the interlayer insulating layer comprises a groove, an orthogonal projection of the groove on the substrate does not coincide with an orthogonal projection of the photosensitive unit on the substrate, and the light-emitting unit covers the groove;
• wherein the photosensitive unit comprises a photodiode;
• wherein the photodiode comprises an N-type doped semiconductor layer and a P-type doped semiconductor layer sequentially arranged on the substrate;
• wherein
• the P-type doped semiconductor layer is electrically connected to a reverse bias voltage signal line;
• a side of the photodiode proximate to the reverse bias voltage signal line connected to the P-type doped semiconductor layer is a connection side;
• and a contour of the orthogonal projection of the groove on the substrate is adjacent to a contour of an orthogonal projection of a portion of the photodiode other than the connection side on the substrate, and
• a plurality of scanning lines, a plurality of reverse bias voltage signal lines and a plurality of signal reading lines, the plurality of scanning lines and the plurality of reverse bias voltage signal lines crossing to define the plurality of pixel units, and each of the plurality of pixel units further comprising a switching transistor;
• wherein
• control electrodes of the switching transistors located in a same row are connected to a same scanning line;
• first electrodes of the switching transistors located in a same column are connected to a same signal reading line;
• second electrodes of the switching transistor in each of the pixel units are connected to the N-type doped semiconductor layer of the photodiode;
• and
• the P-type doped semiconductor layer of the photodiode located in a same column are connected to a same reverse bias voltage signal line.