Water-based high-performance polymer field effect transistors enabled by heat-assisted surfactant elimination

Abstract

Environmentally benign processing technology of polymeric semiconductor is demonstrated to facilitate industrial application of organic electronics. By employing sodium dodecyl sulfate (SDS) as a surfactant and Poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT) as a polymeric semiconductor, a water-borne colloid was synthesized and used for forming the active layer of a field effect transistor. Traditionally, this technology was not successful in realizing high charge carrier mobility, owing to difficulties in identifying an optimal temperature for eliminating the surfactant while maintaining the long-range-ordered π–π stacked structure of the semiconductors. In this work, by utilizing the liquid crystalline nature of the PBTTT, we identified the optimal thermal treatment condition (∼270°C), which is sufficient both for eliminating the SDS and stimulating a second phase transition of the PBTTT. As a result, the PBTTT nanoparticle film cast from the water-borne colloid was successfully sintered to form continuously π–π stacked polymeric semiconductor films, whose high charge carrier mobility of 0.19cm2/Vs, is comparable to those of organic solvents.