Wright Matthew, Lin Rui, Tayebjee Murad J Y, Yang Xiaohan, Veettil Binesh Puthen, Wen Xiaoming, Uddin Ashraf
J Nanosci Nanotechnol. 2015 Mar;15(3):2204-11. doi: 10.1166/jnn.2015.9873.
This report investigates the influence of the solution blend composition of binary bulk heterojunction organic solar cells composed of poly(2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H- cyclopenta[2,1-b:3,4-b'dithiophene-2,6-diy]] (PCPDTBT) and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM). The blend polymer:fullerene composition was varied from 1:1 (50 wt% PC71 BM) to 2:9 (82 wt% PC71 BM). Increasing the amount of polymer in the blend results in the greatest overall absorption, as the donor material PCPDTBT is the main contributor to absorption. However, high polymer content leads to poor photovoltaic performance. For this material combination, the optimum blend polymer:fullerene composition was found to be 2:7. Increasing the fullerene content in the blend led to a significant improvement in the internal quantum efficiency of devices. This was correlated with an increase of the electron mobility, as the fullerene content was increased. Improved electron transport, leading to more balanced transport between electrons and holes, significantly improved the short circuit current density (Jsc) and fill factor (FF).
本报告研究了由聚（2,1,3 - 苯并噻二唑 - 4,7 - 二基[4,4 - 双（2 - 乙基己基）-4H - 环戊并[2,1 - b:3,4 - b']二噻吩 - 2,6 - 二基]]（PCPDTBT）和[6,6] - 苯基C71丁酸甲酯（PC71BM）组成的二元体相异质结有机太阳能电池的溶液共混物组成的影响。共混聚合物：富勒烯的组成从1:1（50 wt％PC71BM）变化到2:9（82 wt％PC71BM）。由于供体材料PCPDTBT是吸收的主要贡献者，共混物中聚合物含量的增加导致总体吸收最大。然而，高聚合物含量导致光伏性能较差。对于这种材料组合，发现最佳的共混聚合物：富勒烯组成为2:7。共混物中富勒烯含量的增加导致器件的内量子效率显著提高。这与电子迁移率的增加相关，因为富勒烯含量增加。改善的电子传输导致电子和空穴之间更平衡传输，显著提高了短路电流密度（Jsc）和填充因子（FF）。
