| 초록 |
Benzo[1,2-b:4,5-b’]dithiophene (BDT) derivatives are among the most widely used electron-donating units in the polymer backbones of polymer solar cells (PSCs). In this study, a series of new conjugated polymers based on BDT unit with alkyl, alkoxy or oligoether as side chains were designed and synthesized for use in bulk-heterojunction polymer solar cells. By replacing alkyl chain (P0O) with alkoxy chain (P1O), higher short circuit current (JSC) and fill factor (FF) were observed. Thus, the power conversion efficiency (PCE) was enhanced about 20%. The increase of JSC and FF was due to the enhancement of crystallinity and hole mobility. The best solar cell efficiency was achieved in P2O device based on oligoether-BDT, which was explained by optimized morphology and charge carrier mobilities. The effects of the side chains on the polymer HOMO energy levels and photovoltaic parameters were investigated. |
