혼합된 반도체성 고분자를 채널로 하는 유기 전계효과 트랜지스터에 관한 연구

Abstract

Organic field-effect transistors (OFETs) have shown considerable potential for widespread use as a crucial building block in flexible organic electronics of the future. π-conjugated polymers have been applied to various functional organic electronic devices with the introduction of the doped polymer, and controllably doping inorganic semiconductors to tune their electrical properties to specific application requirements has been well-established. However, the doping process in the fabrication of solution-processable OFETs remains challenging mainly because of their instability due to the uncontrollable dopant diffusion and low doping efficiencies. In this study, we propose a blending method for substitutional doping of DPP (diketopyrrolopyrrole) units in PBTTT-C14 (Poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]) matrix. For this study, we blended the p-type PBTTT-C14 semiconducting polymer with PDPP2T-TT-OD (Poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)]) polymer having DPP molecular units with n-type properties and fabricated the OFET devices with the thin-films formed by spin-coating of the blended inks as the active layer. From the electrical characterization of the OFET devices with the blended semiconducting polymer films, it was observed that the field-effect mobility was gradually improved and the ambipolar characteristics were enhanced as the ratio of DPP in the thin film increased.