| 초록 |
Two donor-acceptor (D-A) type copolymers based on quinoxaline (Qx) and benzo[1,2-b;4,5-b']dithiophene (BDT) were synthesized altering alkyl chain length of quinoxaline unit. The electron-withdrawing F groups was introduced in the polymers to achieve enhanced Voc. Two polymers were observed similar UV-vis absorption in the range of 564 to 568 nm in solution and 573 to 574 nm in film state. Energy levels also showed similar HOMO, LUMO levels and bandgap. It seems that side chain hardly influenced on optical and electrochemical properties. In photovoltaic properties, however, more short side chain reduce steric hindrance and it leaded to better Jsc 9.66 mA/cm2. As a result, the polymer having shorter side chain indicated the best power conversion efficiency (PCE) of 5.11% with Voc of 0.82 V, Jsc of 9.66 mA/cm2, FF of 0.65%. |
