Enhanced electrical stability of organic thin-film transistors with polymer semiconductor-insulator blended active layers

We report on an enhanced electrical stability of organic thin-film transistors (OTFTs), where an organic semiconductor (poly(didodecylquaterthiophene-alt-didodecylbithiazole) (PQTBTz-C12)) and a polymer insulator (poly(methyl methacrylate) (PMMA)) blended film were used as the active layer, in comparison with a single PQTBTz-C12 OTFT. While both devices exhibit similar electrical performance in terms of mobility and ON/OFF ratios, the blended device is less susceptible to OFF-bias stress. It is suggested that the carboxyl groups of PMMA in the blend may act as suppressors with regards to hole accumulation in the channel, and thus, the PQTBTz-C12/PMMA blend based OTFTs exhibit delayed threshold voltage shifts under OFF-bias stress.