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, 4,40-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 C-61-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. (C) 2013 Elsevier B. V. All rights reserved.