Display substrate and display device

A display substrate, comprising a substrate and a plurality of sub-pixels corresponding to different colors arranged on the substrate, wherein each sub-pixel comprises a pixel driving circuit and an organic electroluminescent diode electrically connected with the pixel driving circuit;

• wherein
• the pixel driving circuit comprises a first transistor, a second transistor and a storage capacitor, a gate electrode of the first transistor is coupled to a first scanning line, a first electrode of the first transistor is coupled to a data line, and a second electrode of the first transistor is coupled to a gate electrode of the second transistor;
• a first electrode of the second transistor is coupled to a first power supply voltage line, a second electrode of the second transistor is coupled to a first electrode of the organic electroluminescent diode, and a second electrode of the organic electroluminescent diode is coupled to a second power supply voltage line;
• a first electrode of the storage capacitor is coupled to the gate electrode of the second transistor, a second electrode of the storage capacitor is coupled to the second electrode of the second transistor, and the storage capacitor is configured to store potential of the gate electrode of the second transistor;
• in a direction perpendicular to the substrate, the display substrate comprises a first metal layer, a first insulating layer, a metal oxide layer, a second insulating layer and a second metal layer which are stacked;
• the metal oxide layer comprises a first pattern as an active layer of the first transistor, a second pattern as an active layer of the second transistor and a capacitor pattern as the first electrode of the storage capacitor;
• the first metal layer comprises a first electrode plate, and there is at least a first overlapping region between an orthographic projection of the first electrode plate on the substrate and an orthographic projection of the capacitor pattern on the substrate to form a first storage capacitor;
• the second metal layer comprises a second electrode plate, and there is at least a second overlapping region between an orthographic projection of the second electrode plate on the substrate and the orthographic projection of the capacitor pattern on the substrate to form a second storage capacitor;
• and
• the first electrode plate and the second electrode plate have same potential;
• wherein the metal oxide layer is a single layer, a double layer or a plurality of layers;
• wherein the metal oxide layer comprises a first oxide layer and a second oxide layer stacked, wherein conductivity of the second oxide layer is lower than that of the first oxide layer, and a band gap of the second oxide layer is greater than that of the first oxide layer.