Xu Wenzhan, Yi Chao, Yao Xiang, Jiang Lili, Gong Xiong, Cao Yong
Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron, Akron 44325, Ohio, United States.
Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
ACS Omega. 2017 May 4;2(5):1786-1794. doi: 10.1021/acsomega.7b00269. eCollection 2017 May 31.
In this study, we report organic solar cells (OSCs) fabricated by a polymer-small molecule: the fullerene ternary active layer. It is found that a significantly enhanced power conversion efficiency contributed to the enhanced short-circuit current density and fill factor (FF). Investigation of absorption spectra and external quantum efficiency spectra indicate that the enhancement in photocurrent originates from the improved light absorption attributed to the small molecule. Further investigations by grazing-incidence wide-angle X-ray scattering, transmission electron microscopy, and atomic force microscopy reveal that charge transport within the ternary active layer is facilitated by a reduced π-π distance between the adjacent polymer chains along the out-of-plane direction, good miscibilities between ternary components, and the rougher surface of the resultant thin film. As a result, the hole mobility of the polymer electron donor and electron mobility of the fullerene electron acceptor are considerably increased, resulting in enhanced FFs. Our studies provide a facile route to realize efficient OSCs.
在本研究中，我们报道了由聚合物-小分子：富勒烯三元活性层制备的有机太阳能电池（OSC）。研究发现，功率转换效率显著提高归因于短路电流密度和填充因子（FF）的增强。吸收光谱和外量子效率光谱研究表明，光电流的增强源于小分子导致的光吸收改善。通过掠入射广角X射线散射、透射电子显微镜和原子力显微镜的进一步研究表明，三元活性层内的电荷传输因沿面外方向相邻聚合物链之间π-π距离减小、三元组分之间良好的混溶性以及所得薄膜更粗糙的表面而得到促进。结果，聚合物电子给体的空穴迁移率和富勒烯电子受体的电子迁移率显著增加，从而提高了填充因子。我们的研究为实现高效有机太阳能电池提供了一条简便途径。
