Organic thin film transistor and preparation method thereof

The invention discloses an organic thin film transistor and a preparation method thereof. The preparation method comprises the following steps of S1, forming a source electrode, a drain electrode anda pixel electrode on a substrate, wherein the source electrode, the drain electrode and the pixel electrode are all prepared from ITO; S2, fully dropwise adding an isopropyl alcohol solution on the substrate obtained in the previous step, standing for a certain time, washing with isopropyl alcohol and drying, and then carrying out oxygen plasma treatment; and S3, sequentially forming an active layer, an organic insulating layer and a grid electrode on the substrate. According to the method, the source electrode, the drain electrode and the pixel electrode are all made of low-cost ITO, and meanwhile, the source electrode, the drain electrode and the pixel electrode are processed by using the isopropyl alcohol solution so as to improve the work function, so that the cost can be lowered, theHOMO energy level of the o