Highly Efficient PCDTBT:PC₇₁ BM Based Photovoltaic Devices without Thermal Annealing Treatment

We propose an effective method to fabricate highly efficient organic photovoltaic cells based on poly N−9"-hepta-decanyl-2, 7-carbazole-alt-5,5-(4'7'-di-2-thienyl-2'1'3'-b-enzothiadiazole):6,6-phenyl C₇₁−butyric acid methyl ester (PCDTBT:PC₇₁BM). A power conversion efficiency of as high as 5.6% and a fill factor of 53.7% are achieved from the optimized cells. The influence of surface morphology of the active layer on the performance of the cells is also investigated.