| 초록 |
Two-dimensional(2D)-conjugated copolymers based on benzo[1,2-b:4,5-b’]dithiophene (BDT) with 5-(2-ethylhexyl)-2,2'-bithiophene or 5-(2-ethylhexylthio)-2,2'-bithiophene, respectively, and 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole(DTBT) were designed and synthesized as donor materials for organic photovoltaic cells(OPVs). The introduction of alkylthio on the side chain of low bandgap polymer is effective in lowing HOMO energy level to attain higher open-circuit voltage (Voc). The HOMO energy level of PBDTBT-S-DTBT with alkylthio group was down-shifted by 0.08 eV compared to that of the corresponding alkyl-substituted analogue PBDTBT-DTBT. As a result, the improved Voc of PBDTBT-S-DTBT led to a higher PCE. |
