Enhanced device performance of polymer solar cells by planarization of quinoxaline derivative in a low-bandgap polymer
作者:Yoonkyoo Lee、Young Min Nam、Won Ho Jo
DOI:10.1039/c1jm10877h
日期:——
A series of low-bandgap alternating copolymers consisting of electron-accepting quinoxaline derivatives and electron-donating carbazole or fluorene were synthesized via a Suzuki coupling reaction. For the purpose of improving the molecular packing of polymer chains and to enhance the charge carrier mobility in the packing direction, a new quinoxaline derivative, 10,13-bis-(4-octyl-thiophene-2-yl)-dibenzo[a,c]phenazine, which is expected to have planar polycyclic structure, was synthesized and introduced as a new building block of alternating copolymers instead of frequently-used 5,8-dithien-2-yl-2,3-diphenylquinoxaline. Copolymers with the planar quinoxaline derivative exhibited better optical and structural properties compared to copolymers with a less planar quinoxaline derivative. A power conversion efficiency was achieved up to 3.8% when the copolymer with planar quinoxaline derivative was blended with [6,6]-phenyl-C71-butyric acid methyl ester as an active layer material in bulk heterojunction solar cells.
通过铃木偶联反应合成了一系列由电子接受型喹喔啉衍生物和电子捐赠型咔唑或芴组成的低带隙交替共聚物。为了改善聚合物链的分子堆积,提高电荷载流子在堆积方向上的迁移率,合成了一种新的喹喔啉衍生物--10,13-双-(4-辛基噻吩-2-基)-二苯并[a,c]吩嗪,这种衍生物有望具有平面多环结构,并被用作交替共聚物的新结构单元,而不是常用的 5,8-二噻吩-2-基-2,3-二苯基喹喔啉。与平面度较低的喹喔啉衍生物共聚物相比,平面度较高的喹喔啉衍生物共聚物具有更好的光学和结构特性。将含有平面喹喔啉衍生物的共聚物与[6,6]-苯基-C71-丁酸甲酯混合,作为体异质结太阳能电池的活性层材料,功率转换效率可达 3.8%。