Significant impact of monomer curvatures for polymer curved shape composition on backbone orientation and solar cell performances

Abstract In the present study, linear or curve-shaped donor units, quinacridone (Qc) and benzo[2,1-b:3,4-b′]dithiophene (BDP), and spacers were introduced for polymerization of four D–A type polymers (PBDPOx-biT, PBDPOx-TT, PQcOx-biT, and PQcOx-TT). The UV–vis absorption spectra of PBDPOx-biT, PQcOx-TT (linear shaped polymer) films were red-shifted compared with the solution absorption, whereas that of a PBDPOx-TT, PQcOx-biT (curve shaped polymer) film was blue-shifted. PBDPOx-biT, PQcOx-TT had high crystallinity. Linear polymers prefer regular and crystalline domains in the film state and lead to more efficient organic photovoltaic (OPV) devices. PQcOx-TT possesses a PCE value of up to 3.4%.