Enhancing the performance of porphyrin based solar cells by the Bipy coordination

Solution processed organic solar cells (OSCs) often suffer from low charge mobilities partially due to the disordered non-crystalline or amorphous morphology of their films. In this study, 4,4′-bipyridyl (Bipy) is introduced to coordinate a zinc(II) porphyrin to form porphyrin complexes. A significant enhanced hole mobility and solar cell device performance are attained when the ratio of Bipy is 0.25 in blend films with [6, 6]-phenyl C₆₁-butyric acid methyl ester (PC₆₁BM). When [6, 6]-phenyl C₇₁-butyric acid methyl ester (PC₇₁BM) was used instead of PC₆₁BM, the PCE is enhanced to 2.83% in the presence of 0.25 equiv Bipy, which is an increase of 53% compared to that without Bipy.