Direct arylation polycondensation: A promising method for the synthesis of highly pure, high-molecular-weight conjugated polymers needed for improving the performance of organic photovoltaics

Alternating conjugated polymers of ethylenedioxythiophene and fluorene are prepared using three different synthetic methods to investigate the effects of these synthetic methods on the purity, field-effect transistor (FET) performance, and organic photovoltaic (OPV) performance of the polymer. In this study, microwave-assisted direct arylation polycondensation is used to obtain a high-purity, high-molecular-weight (147 kDa) polymer. This pure polymer exhibits a high FET hole mobility of 1.2 × 10^-3 cm² V ^-1 s^-1 and high OPV performance with a power conversion efficiency of 4%, even though the polymer forms an amorphous film, which absorbs in a limited region of the spectrum. Field-effect transistor and organic photovoltaic performances strongly depend on the synthetic methods of a polymer owing to different purity and molecular weight. A high-purity, high-molecular-weight polymer exhibits a high FET hole mobility of 1.2 × 10^-3 cm² V^-1 s^-1 and high OPV performance with a power conversion efficiency of 4%, even though the polymer forms an amorphous film, which absorbed in a limited region of the spectrum.