Novel Semiconductors Based on Functionalized Benzod,dithieno3,2-b;4,5-bdithiophenes (BTDTs) and the Effects of Thin Film GrowthConditions on Organic Field Effect Transistor Performance

摘要

A series of benzo[d,d]thieno[3,2-b;4,5-b]dithiophene (BTDT) derivatives, end-functionalized with phenyl (P-BTDT), benzothiophenyl (BT-BTDT) were synthesized and characterized. A facile, one-pot synthesis of BTDT was developed which enables the efficient realization of a new BTDT-based semiconductor series for organic thin-film transistors (OTFTs). The crystal structure of P-BTDT was determined via single-crystal X-ray diffraction. Various combinations of surface treatment methods, substrate temperature, and deposition flux rate sequences have significant effects on device performance. Films deposited on octadecyltrichlorosilane (OTS)- treated SiO_2 substrates under properly adjusted substrate temperature and deposition flux rate achieve an efficaceous compromise between high film crystallinity and good film grain interconnectivity, resulting in good OTFT performance, with mobility greater than 0.70 cm~2V~(-1)s~(-1) and I_(on)/I_(off) greater than 108.