| 초록 |
We have used Stille coupling polymerization to synthesize new crystalline deep HOMO level polymers, PhBDT-BT and PhBDT-DTBT, which consist of 4,8-bis(2-octyldodecyloxyphenyl)-benzo-[1,2-b:4,5-b’] dithiophene (PhBDT) as an effective electron donor unit and 4,7-dibromobenzo [c] thiadiazole (BT), or 4,7-bis(5-bromothiophen-2-yl)benzo[c] thiadiazole (DTBT)units as electron acceptor units. Photovoltaic devices fabricated from the PhBDT-DTBT/PC70BM (1:2) blend system exhibited an excellent photovoltaic (PV) performance with a Voc value of 0.73 V, a short-circuit current density (Jsc) value of 7.06 mA/cm2, a fill factor (FF) value of 0.67, and a promising power conversion efficiency (PCE) of 3.5%. In addition, organic thin film transistor (OTFT) devices using PhBDT-DTBT as the semiconductor also showed excellent performance with a value of hole mobility of 4.7 x -10-2 cm2 V-1s-1. In the PhBDT-DTBT, the thiophene bridge between the PhBDT and benzothiadiazole provides enough space for the interdigitation of the bulky alkoxyphenyl side chains, increasing the planarity with enhanced π–π stacking. |
