Effects of thermal annealing conditions on the electrical characteristics of TES-ADT thin-film transistors

We investigated the annealing temperature and exposure period dependence of electrical characteristics of bottom-gate/top-contact solution-processed organic thin-film transistors (TFTs) fabricated on ITO-patterned substrates using 5,11-bis(triethylsilylethynyl)anthradithiophene(TES-ADT), PVP-co-PMMA, and silver as the semiconductor, gate dielectric, and drain and source electrodes, respectively. The semiconductor films were thermally annealed at 60, 80, and 90 °C for 60 min; then, the optimal annealing temperature, which proved to be 80 °C, was considered to investigate the impact of exposure time by exposing the film for 30, 60, and 90 min. Experimental results indicate that the medium temperature resulted in the better electrical performance, whereas the high temperature proved to be detrimental by causing ruptures through the film. According to our study, TES-ADT film annealed at 80 °C for 60 min results in the finest semiconductor microstructure, which improves the electrical characteristics, whereas lower or higher temperatures and shorter or longer annealing times lead to an unfavorable structure that hampers charge transport in the film.