Copolymers based on benzodithiophene and quinoxaline, represented by 4,8-bis(5-(3,4,5-tris(octyloxy)phenyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene (TOBDT) and 2,3-diphenyl-5,8-di(thiophen-2-yl)quinoxaline (TQ1) or 10,13-bis(4-(2-ethylhexyl)thiophen-2-yl)dibenzo[a,c]phenazine (TQ2), were synthesized via a Stille coupling reaction. By increasing the conjugation in the TQ2 unit, the polymer based on TQ2 showed a narrower band gap (Eg), a lower highest occupied molecular orbital energy level and enhanced interchain π–π interactions. Polymer solar cells based on TQ2 showed a simultaneous enhancement of the open-circuit voltage (Voc), short-circuit current density (Jsc) and fill factor (FF) compared with polymer solar cells based on the TQ1 polymer. A good power conversion efficiency of 4.24% was achieved by solar cells based on the TQ2 polymer and [6,6]-phenyl-C71-butyric acid methyl ester composite. These preliminary results indicate that increasing the acceptor unit (quinoxaline) conjugation is an effective way of improving the performance of polymer solar cells.
基于苯并二
噻吩和
喹喔啉的共聚物,以4,8-双(5-(3,4,5-三(辛氧基)苯基)
噻吩-2-基)苯并[1,2-b:4,5-b'表示]二
噻吩 (TOBDT) 和 2,3
-二苯基-5,8-二(
噻吩-2-基)
喹喔啉 (TQ1) 或 10,13-双(4-(2-乙基己基)
噻吩-2-基)二苯并[ a,c]
吩嗪 (TQ2) 通过 Stille 偶联反应合成。通过增加TQ2单元的共轭,基于TQ2的聚合物表现出更窄的带隙(Eg)、更低的最高占据分子轨道能级和增强的链间π-π相互作用。与基于TQ1聚合物的聚合物太阳能电池相比,基于TQ2的聚合物太阳能电池的开路电压(Voc)、短路电流密度(Jsc)和填充因子(FF)同时提高。基于TQ2聚合物和[6,6]-苯基-C71-
丁酸甲酯复合材料的太阳能电池实现了4.24%的良好功率转换效率。这些初步结果表明,增加受体单元(
喹喔啉)共轭是提高聚合物太阳能电池性能的有效途径。