New donor-acceptor copolymer containing dialkoxy naphthalene and carbonylated thieno[3,4-b]thiophene for OTFT and OPV

Abstract

A new copolymer (PONTET), composed of dialkoxy napthalene as donor and a carbonylated thieno [3,4-b]thiophene group as an acceptor, was obtained by Suzuki coupling polymerization. The number average molecular weight (M (n) ) of PONTET is 6.4 kg mol(-1) with a polydispersity index of 1.20, determined by gel permeation chromatography using chloroform. PONTET showed broad absorption with a maximum at 534 nm in solution and 618 nm in a thin film, respectively. The hole mobility of PONTET was 1.5x10(-3) cm(2)/Vs and the I (on) /I (off) ratio was 7.7x10(4). The maximum power conversion efficiency of a PONTET:PC70BM (1:4)-based solar cell reached 1.3% with an open circuit voltage (V (oc) ) of 0.56 V, a short circuit current density (J (sc) ) of 5.6 mA/cm(2), and a fill factor (FF) of 41.3%.