High mobility organic thin film transistor and efficient photovoltaic devices using versatile donor–acceptor polymer semiconductor by molecular design

In this work, we report a novel donor–acceptor based solution processable low band gap polymer semiconductor, PDPP–TNT, synthesized via Suzuki coupling using condensed diketopyrrolopyrrole (DPP) as an acceptor moiety with a fused naphthalene donor building block in the polymer backbone. This polymer exhibits p-channel charge transport characteristics when used as the active semiconductor in organic thin-film transistor (OTFT) devices. The hole mobilities of 0.65 cm2 V−1s−1 and 0.98 cm2 V−1s−1 are achieved respectively in bottom gate and dual gate OTFT devices with on/off ratios in the range of 105 to 107. Additionally, due to its appropriate HOMO (5.29 eV) energy level and optimum optical band gap (1.50 eV), PDPP–TNT is a promising candidate for organic photovoltaic (OPV) applications. When this polymer semiconductor is used as a donor and PC71BM as an acceptor in OPV devices, high power conversion efficiencies (PCE) of 4.7% are obtained. Such high mobility values in OTFTs and high PCE in OPV make PDPP–TNT a very promising polymer semiconductor for a wide range of applications in organic electronics.