Side Chain Engineering of Copolymers Based on Bithiazole and Benzodithiophene for Enhanced Photovoltaic Performance
作者:Qinqin Shi、Haijun Fan、Yao Liu、Jianming Chen、Lanchao Ma、Wenping Hu、Zhigang Shuai、Yongfang Li、Xiaowei Zhan
DOI:10.1021/ma200576y
日期:2011.6.14
Four new copolymers P1–P4 containing the same backbone of bithiazole acceptor unit and benzodithiophene donor unit but different side chain pattern were synthesized by Pd-catalyzed Stille coupling. The effect of the side chains on backbone conformation, solubility, absorption spectra, energy levels, charge transport, blend film morphology, and photovoltaic properties of the polymers were experimentally
通过Pd催化的Stille偶联合成了四种新的共聚物P1 – P4,它们具有相同的噻唑受体单元主链和苯并二噻吩供体单元主链,但侧链模式不同。侧链对主链构象,溶解度,吸收光谱,能级,电荷传输,混合膜形态和聚合物的光伏性能的影响进行了实验和理论上的研究。主链的平面增大的顺序P3 < P4 < P1 ≈ P2。随着主链平面度的增加,聚合物在膜中的最大吸收峰出现红移,从448 nm移至544 nm,HOMO从-6.0向上移至-6.0 eV,LUMO从-2.6向下移至-2.9 eV,并增加空穴迁移率从4.7×10 –4到0.06 cm 2 V –1 s –1。当增加聚合物主链的平面度时,聚合物:PC 71 BM共混物中的相分离尺寸增加。基于P4:PC 71 BM(1:1,w / w)的聚合物太阳能电池在AM 1.5、100 mW cm –2下显示出2.54%的最高功率转换效率归因于宽吸收,高迁移率和合