摘要
D-A_1-D-A_2型窄带隙共聚合物较传统的D-A型聚合物而言,不同的"A"单元之间进行互补,拓宽了对可见光的吸收范围。本论文以3.6-二(2-噻吩基)-1.4-二酮吡咯并吡咯(DPP)为"A_1"单元,4,7-二(5-溴-4-十二烷基-2-噻吩基)-苯并噻二唑(BT)和2,5-二(5-溴-4-己基-2-噻吩基)-5-辛基噻吩并[3,4-c]吡咯-4,6-二酮(TPD)为"A_2"单元,采用简单环保的直接芳基化缩聚法制备了D-A_1-D-A_2型窄带隙聚合物PDPP-TT(6)-BT、PDPP-TTT(6)-BT、PDPP-TTT(6)-TPD[1-2],并研究不同"A"单元类型和"D"单元个数对聚合物性能的影响。分别与受体材料PC_(71)BM共混作为活性层制备聚合物太阳能电池器件并测试其光伏性能,结果发现:不同的A_2单元结构,导致聚合物具有不同的光伏性能,TPD做受体单元的性能强于BT;三个噻吩单元比两个噻吩单元更利于电荷传输,基于PDPP-TTT(6)-TPD器件的光电转换效率最大,PCE为4.30%。
D-A_1-D-A_2 type low bandgap conjugated polymers can broaden the scope of visible light absorption. In this paper, three D-A_1-D-A_2 type low bandgap conjugated polymers P1, P2 and P3 were synthesized through direct arylation polycondensation. DPP was used as the "A_1" unit, BT or TPD were taken as "A_2" unit and the bithiophene or bithiophene with hexyl chain served as "D" units. BHJ solar cells were fabricated from photoactive layer composed of PDPP-TT(6)-BT, PDPP-TTT(6)-BT or PDPP-TTT(6)-TPD, respectively, which was used as the electron donor and the PC_(71)BM was used as the electron acceptor. The results showed that different A_2 unit structure can lead to the polymers with different photovoltaic performance. The performance of TPD unit is better than that of BT unit. Three-thiophene unit is more effective for charge transfer than that of two-thiophene unit. The highest photoelectric conversion efficiency of 4.30% was achieved from the device-based PDPP-TTT(6)-TPD.
引文
[1]Dang,D.;Chen,W.;Yang,R.;Zhu,W.Chem.Commun.2013,49:9335.
[2]Tao,Q.;Xia,Y X.;Xu,X F.;Svante,H.Macromolecules.2015,48:1009.
