Preparation method of white light OLED

The invention provides a preparation method of a white light OLED, which comprises the following steps: firstly, cleaning and drying ITO glass, and then, carrying out plasma bombardment pretreatment; then, transferring the ITO glass after treatment into a film plating machine; and simultaneously, sequentially transferring materials for an electronic blocking layer, materials for a hole transport layer, materials for a light-emitting layer, materials for an electron transfer layer and materials for a cathode layer into the film plating machine for evaporating. The evaporating process of the light-emitting layer comprises the following steps: firstly, carrying out double-source co-evaporation on a main material and a blue doping agent, wherein the ratio of the blue doping agent is 2%; and finally, carrying out three-source co-evaporation on the main material, the blue doping agent and a red doping agent, wherein the ratio of the blue doping agent is 2%, and the ratio of the red doping agent is 6%. In the invention, only red and blue doping materials are doped in the main material of the light-emitting layer, thus the doping ratio can be controlled easily, and the white light emitteda the prepared device is uniform; and the invention has the advantages of simple process and low cost.