摘要： Conjugated polymers with D-π-A backbone structures have been intensively investigated and have largely promoted the rapid progress of organic solar cells (OSCs). However, as one of the simplest electron-accepting (A) units, phthalimide (PhI), only attracts less attention to construct promising D-π-A photovoltaic polymers in OSC community. Thus the correlations between the chemical structure-optoelectronic properties-photovoltaic performance need to be systematically investigated. Here, we combined the PhI moiety with the electron-donating (D) unit benzodithiophene (BDT) to synthesize two D-π-A copolymers PE80 and PE81, where the π-bridge corresponds to the thiophene (T) and thieno[3,2-b]thiophene (TT) respectively. When blended with a low bandgap (Eg=1.33 eV) non-fullerene acceptor Y6, PE81 achieved a power conversion efficiency (PCE) of 10.21% with an open circuit voltages (VOC) of 0.90 V, which are much higher than those of PE80:Y6 device (PCE = 4.11% and VOC = 0.88 V). Our results indicate that PhI is also a promising electron-deficient unit to construct photovoltaic polymers and using TT π-bridge is simple strategy to improve the photovoltaic performance of D-π-A polymers.