초록 |
An amino-functionalized polymer, poly[(9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dihexylfluorene)] (PFN), was introduced to different amounts and types of acid derivatives such as acetic acid (AA), 4-trifluoromethyl benzoic acid (CF3BA), trifluoroacetic acid (CF3AA), and 4-toluene sulfonic acid (TsOH) to investigate the effect of amounts and types of acid additives on the device performances. It was applied as the cathode buffer layer in inverted polymer solar cells (PSCs) with PTB7-Th:PC71BM blend as the active layer. The power conversion efficiency (PCE) of the device with pristine ZnO was 8.7%, while the PCE of the devices with the 1.0 equivalent of AA, CF3BA, CF3AA, and TsOH was 9.9, 10.3, 10.3, and 10.6%, respectively. The device performances and the reduced trap-assisted recombination matched the trend of the acid dissociation constant. |