Novel Photoactive Fluorene-Based Terpolymers Incorporating Carbazole for Photovoltaic Application

A series of novel photoactive conjugated terpolymers based on N-alkyl carbazole, 9,9-didecylfluorene, and bis(thienyl)benzothiadiazole were synthesized by the Pd-catalyzed Suzuki polymerization method with various molar ratios of the carbazole derivatives. Electron-deficient benzothiadiazole and electron-rich carbazole moieties were incorporated into the polymer backbone to obtain the broad absorption spectrum and to improve the hole-transporting characteristics, respectively. The polymer solar cell (PSC) was fabricated with a layered structure of ITO/PEDOT: PSS/polymer:C-71-PCBM (1:3)/LiF/Al. The best performance of PSC was obtained at P1:C-71-PCBM whose reaches a power conversion efficiency (POE) of 2.62%, with a short circuit current density (J(SC)) of 8.61 mA/cm(2), an open circuit voltage (V-OC) of 0.82 V, and a fill factor (FF) of 0.37 under AM 1.5 G irradiation (100 mW/cm(2)).