Diaza-substituted conjugated polymers based on naphthalene diimide for n-type field-effect transistors

Abstract

Two conjugated polymers (PNDI-TPzT and PNDI-TPmT) based on naphthalene diimide as acceptor and diaza-substituted thiophene-phenyl-thiophene with para- and meta-position as co-units were designed and synthesized. The reported polymer (PNDI-TPaT) with ortho-substitution was also used for comparison. The different aza-substitution exerted effect on the absorption, energy levels, microstructure, and field-effect transistor performances. All the diaza-substituted conjugated polymers exhibited n-type transport characteristics under vacuum conditions. PNDI-TPmT with meta-substitution which had ordered structure and π−π stacking exhibited the highest field-effect transistor performances with the mobility of about 0.07 cm2V−1s−1.