White organic light-emitting diode display substrate including switching TFT and light-shielding layer arranged to prevent negative drift

An organic light-emitting diode (OLED) display substrate, comprising:

• a base substrate;
• and
• a plurality of pixel units arranged on the base substrate, wherein each pixel unit comprises a plurality of subpixel units, and each subpixel unit comprises a switching thin film transistor (TFT),
• wherein the OLED display substrate further comprises a light-shielding layer arranged between an OLED and the switching TFT, and an orthogonal projection of the light-shielding layer onto the base substrate completely covers an orthogonal projection of a semiconductor region of the switching TFT onto the base substrate, wherein each pixel unit comprises a red subpixel unit, a green subpixel unit, a blue subpixel unit and a white subpixel unit, the red subpixel unit comprises a red color filter and a first switching TFT, the green subpixel unit comprises a green color filter and a second switching TFT, the blue subpixel unit comprises a blue color filter and a third switching TFT, the white subpixel unit comprises a white color filter and a fourth switching TFT;
• wherein the light-shielding layer completely covers an orthogonal projection of a semiconductor region of the first switching TFT in the red subpixel unit onto the base substrate, an orthogonal projection of a semiconductor region of the second switching TFT in the green subpixel unit onto the base substrate, an orthogonal projection of a semiconductor region of the third switching TFT in the blue subpixel unit onto the base substrate, an orthogonal projection of a semiconductor region of the fourth switching TFT in the white subpixel unit onto the base substrate.