Du Zhifang, Luong Hoang Mai, Sabury Sina, Therdkatanyuphong Pattarawadee, Chae Sangmin, Welton Claire, Jones Austin L, Zhang Junxiang, Peng Zhengxing, Zhu Ziyue, Nanayakkara Sadisha, Coropceanu Veaceslav, Choi Dylan G, Xiao Steven, Yi Ahra, Kim Hyo Jung, Bredas Jean-Luc, Ade Harald, Reddy G N Manjunatha, Marder Seth R, Reynolds John R, Nguyen Thuc-Quyen
Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA.
School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Tech Polymer Network, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Mater Horiz. 2023 Nov 27;10(12):5564-5576. doi: 10.1039/d3mh01133j.
We report on the use of molecular acceptors (MAs) and donor polymers processed with a biomass-derived solvent (2-methyltetrahydrofuran, 2-MeTHF) to facilitate bulk heterojunction (BHJ) organic photovoltaics (OPVs) with power conversion efficiency (PCE) approaching 15%. Our approach makes use of two newly designed donor polymers with an opened ring unit in their structures along with three molecular acceptors (MAs) where the backbone and sidechain were engineered to enhance the processability of BHJ OPVs using 2-MeTHF, as evaluated by an analysis of donor-acceptor (D-A) miscibility and interaction parameters. To understand the differences in the PCE values that ranged from 9-15% as a function of composition, the surface, bulk, and interfacial BHJ morphologies were characterized at different length scales using atomic force microscopy, grazing-incidence wide-angle X-ray scattering, resonant soft X-ray scattering, X-ray photoelectron spectroscopy, and 2D solid-state nuclear magnetic resonance spectroscopy. Our results indicate that the favorable D-A intermixing that occurs in the best performing BHJ film with an average domain size of ∼25 nm, high domain purity, uniform distribution and enhanced local packing interactions - facilitates charge generation and extraction while limiting the trap-assisted recombination process in the device, leading to high effective mobility and good performance.
我们报告了使用分子受体（MAs）和用生物质衍生溶剂（2-甲基四氢呋喃，2-MeTHF）处理的供体聚合物来制备体异质结（BHJ）有机光伏电池（OPV），其功率转换效率（PCE）接近15%。我们的方法利用了两种结构中带有开环单元的新设计供体聚合物以及三种分子受体（MAs），通过对供体-受体（D-A）混溶性和相互作用参数的分析评估，对其主链和侧链进行了工程设计，以提高使用2-MeTHF的BHJ OPV的可加工性。为了理解PCE值在9%-15%范围内随组成变化的差异，使用原子力显微镜、掠入射广角X射线散射、共振软X射线散射、X射线光电子能谱和二维固态核磁共振光谱在不同长度尺度上对表面、体相和界面BHJ形态进行了表征。我们的结果表明，在性能最佳的BHJ薄膜中发生的有利的D-A混合，其平均域尺寸约为25 nm，域纯度高，分布均匀且局部堆积相互作用增强，促进了电荷的产生和提取，同时限制了器件中的陷阱辅助复合过程，从而导致高有效迁移率和良好性能。
