Synthesis and Photo-Electrical Properties of the -(D-A₁)_m-(D-A₂)_n-Type Random Terpolymers Based on Thienopyrazine

-(D-A₁)_m-(D-A₂)_n-type random terpolymers were prepared by Stille coupling polymerization,in which benzodithiophene (BDT) derivative was chosen as donor unit(D) and thienopyrroledione (TPD) derivative (A₁) and thienopyrazine (TP) derivative (A₂) were chosen as corporate acceptor units.Meanwhile,the corresponding copolymer based on BDT and TP was prepared.The polymers were characterized by ¹H-NMR,GPC and TG.The photo-electrical properties were measured by UV-visible spectra and cyclic voltammetric curves.The solar cells with these polymers as donor materials were fabricated and the corresponding photovoltaic performance was studied.Results show that the terpolymers have higher relative molecular weight and thermal stability.At the same time,they have stronger and broader absorption under the solar light and relative deeper HOMO (LUMO) energy levels.As a result,the photoelectric conversion efficiency (PCE) of 1.22% based on the random terpolymer P2 is better than the PCE of 1.15% based on the bipolymer P1.