Liu Xiaohui, Li Xiaodong, Wang Lei, Fang Junfeng, Yang Chuluo
Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
School of Physics and Materials Science, Ministry of Education Nanophotonics & Advanced Instrument Engineering Research Center, East China Normal University, Shanghai 200062, China.
Nanoscale. 2020 Feb 27;12(8):4945-4952. doi: 10.1039/c9nr10495j.
Ideal morphological features are of particular importance to produce high performance all-polymer solar cells (all-PSCs), in which active blends generally involve unfavorable phase separation due to complicated intermixing. Developing a suitable processing solvent and additive is an effective and versatile approach to manipulate the morphology of the blends. This study demonstrates the synergistic effects of the processing solvent and additive on the photovoltaic performances of all-PSCs composed of a conjugated copolymer J71 donor and a typical N2200 acceptor. A low boiling point chloroform (CF) solvent combined with 1% 1,8-diiodoctane (DIO) additive was identified as the optimal processing condition to treat the J71:N2200 blends. Consequently, the all-PSCs prepared from CF + 1% DIO processing achieved an outstanding efficiency of 9.34% with an ultrahigh fill factor of 77.86%, which is among the top values for the current all-PSC systems. Owing to the low JSC, just a moderate efficiency of 7.28% was achieved for the device prepared from chlorobenzene (CB) + 1% DIO processing despite its high FF. The electron microscopy tests revealed that the CF solvent was superior to the CB solvent to obtain uniform morphologies and the addition of the DIO additive could further lead to more favorable phase separation and domain size. Moreover, the results of charge generation, transport, and recombination analysis correlate well with the remarkable photovoltaic properties. Our results highlight the critical significance of selecting the appropriate processing solvent and additive to produce high performance all-PSCs.
理想的形态特征对于制备高性能全聚合物太阳能电池（全聚合物太阳能电池）尤为重要，在这种电池中，由于复杂的混合作用，活性共混物通常会出现不利的相分离。开发合适的加工溶剂和添加剂是控制共混物形态的一种有效且通用的方法。本研究展示了加工溶剂和添加剂对由共轭共聚物J71供体和典型的N2200受体组成的全聚合物太阳能电池光伏性能的协同作用。一种低沸点氯仿（CF）溶剂与1% 1,8 - 二碘辛烷（DIO）添加剂相结合被确定为处理J71:N2200共混物的最佳加工条件。因此，由CF + 1% DIO加工制备的全聚合物太阳能电池实现了9.34%的优异效率以及77.86%的超高填充因子，这在当前全聚合物太阳能电池系统中处于顶尖水平。由于短路电流密度较低，尽管由氯苯（CB） + 1% DIO加工制备的器件填充因子较高，但仅实现了7.28%的中等效率。电子显微镜测试表明，CF溶剂在获得均匀形态方面优于CB溶剂，并且添加DIO添加剂可进一步导致更有利的相分离和域尺寸。此外，电荷产生、传输和复合分析的结果与显著的光伏性能密切相关。我们的结果突出了选择合适的加工溶剂和添加剂以制备高性能全聚合物太阳能电池的关键意义。
