| 초록 |
Recently the necessity of improving open circuit voltage (Voc) has attracted much attention in organic photovoltaic cells. Voc is known to be proportional to the energy difference between the highest occupied molecular orbital (HOMO) of the donor and the lowest unoccupied molecular orbital (LUMO) of the acceptor. Based on this principle, three analogs of [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) were modified for increasing the Voc of bulk-heterojunction solar cells via raising the LUMO level of the acceptor. In this study, we synthesized fullerene derivatives containing thiophene, thieno[3,2-b]thiophene and dithieno[2,3-b:2',3'-d]thiophene which could raise the LUMO due to electron-donating properties. The electrochemical and optical properties of PCBM derivatives are discussed. We also investigated organic photovoltaic devices using these PCBM derivatives and measured their device performances. |
