Naphtho[2,3-c][1,2,5]thiadiazole-based conjugated polymers

Abstract

Donor-acceptor type copolymers employed naphtho[2,3-c][1,2,5]thiadiazole (NT) were synthesized to achieve low band gaps. As the same analogue of well-known PCZ-DTBT and PDTDPP-BT reported previously, carbazole (CZ) and dithiophene diketopyrrolopyrrole (DTDPP) units were selected as comonomers for photovoltaic and OFET applications, respectively. The resulting polymers, PCZ-DTNT and PDTDPP-NT with the molecular weight of 15,000 g/mol and 60,000 g/mol, exhibit the energy band gap of 1.74 eV and 1.24 eV, respectively. Preliminary photovoltaic performance of PCZ-DTNT shows the power conversion efficiency of 1.3% on conventional cells. PDTDPP-NT exhibits almost balanced ambipolar characteristics with the hole and electron mobility of 2.48 cm2 V-1s-1 and 2.04 cm2 V-1s-1 on FET devices.