Design and characterization of methoxy modified organic semiconductors based on phenyl[1]benzothieno[3,2-b][1]benzothiophene

Two environmentally and thermally stable [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives, BOP-BTBT and DBOP-BTBT are successfully synthesized and analyzed as active layers in organic thin film transistors. The effects of methoxy on BTBT based OTFT materials are reported for the first time. The experimental results show an excellent optimization influence of methoxy group on the OTFT performance with an improved hole transport mobility up to 0.63 cm2 V−1 s−1 (BOP-BTBT) and 3.57 cm2 V−1 s−1 (DBOP-BTBT). Meantime the mono- and bis-substituted derivatives are compared in terms of their physical properties and device performance. We find that the threshold voltage decreases when more methoxy groups are introduced.