An effective method to minimize the leakage current in organic thin-film transistors by using blends of various molecular weights

We report on an effective method to minimize the leakage current in an organic thin-film transistor (OTFT) by using a polymeric gate insulator, poly(vinyl phenol) (PVP). When the molecular weight (M_w) of the PVP varies, only the leakage current is affected under constant remaining electrical parameters. More importantly, through a binary mixing between two different M_w, it is found that the leakage current can be minimized. This is attributed to a reduction of the free volume in the blended PVP layer, leading to a more vigorous cross-linking reaction, as compared to a single molecular weight PVP.