A low bandgap conjugated polymer bearing a phenazine moiety for application in organic solar cells

Abstract

2-Fluorophenazine, a accepter unit, was prepared for the synthesis of conjugated polymers for application in organic solar cells. The introduction of a phenazine moiety containing fused phenyl groups is key since it reduces the energy levels of the HOMOs in conjugated polymers. Thus, conjugated polymers containing mono-fluorophenazine, thiophene, and benzodithiophene were synthesized using the Stille coupling reaction to generate PBDT-FPz, PBDT-TFPz, and PBDT-DTFPz, and their HOMO energy levels were determined to be - 5.86, - 5.76, and - 5.60 eV, respectively. The device based on PBDT-DTFPz:PC71BM exhibited the photovoltaic performance of 1.69%.