The rise in power conversion efficiency of organic photovoltaic (OPV) devices over the last few years has been driven by the emergence of new organic semiconductors and the growing understanding of morphological control at both the molecular and aggregation scales. Non-fullerene OPVs adopting p-type conjugated polymers as the donor and n-type small molecules as the acceptor have exhibited steady progress, outperforming PCBM-based solar cells and reaching efficiencies of over 15% in 2019. This review starts with a refreshed discussion of charge separation, recombination, and V OC loss in non-fullerene OPVs, followed by a review of work undertaken to develop favorable molecular configurations required for high device performance. We summarize several key approaches that have been employed to tune the nanoscale morphology in non-fullerene photovoltaic blends, comparing them (where appropriate) to their PCBM-based counterparts. In particular, we discuss issues ranging from materials chemistry to solution processing and post-treatments, showing how this can lead to enhanced photovoltaic properties. Particular attention is given to the control of molecular configuration through solution processing, which can have a pronounced impact on the structure of the solid-state photoactive layer. Key challenges, including green solvent processing, stability and lifetime, burn-in, and thickness-dependence in non-fullerene OPVs are briefly discussed.

中文翻译：

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非富勒烯聚合物太阳能电池综述：从器件物理到形态控制

在过去几年中，有机光伏 (OPV) 设备的功率转换效率的提高是由于新型有机半导体的出现以及对分子和聚集尺度上形态控制的日益了解所推动的。以 p 型共轭聚合物为供体、n​​ 型小分子为受体的非富勒烯 OPV 表现稳定，2019 年性能优于 PCBM 基太阳能电池，效率超过 15%。非富勒烯 OPV 中的电荷分离、重组和 V OC 损失，随后回顾了为开发高器件性能所需的有利分子配置而开展的工作。我们总结了几种用于调整非富勒烯光伏共混物纳米级形态的关键方法，并将它们（在适当的情况下）与基于 PCBM 的对应物进行比较。特别是，我们讨论了从材料化学到溶液处理和后处理的问题，展示了这如何导致增强的光伏性能。特别注意通过溶液处理控制分子构型，这会对固态光敏层的结构产生显着影响。简要讨论了主要挑战，包括非富勒烯 OPV 的绿色溶剂加工、稳定性和寿命、老化和厚度依赖性。我们讨论了从材料化学到溶液处理和后处理的问题，展示了这如何导致增强的光伏特性。特别注意通过溶液处理控制分子构型，这会对固态光敏层的结构产生显着影响。简要讨论了主要挑战，包括非富勒烯 OPV 的绿色溶剂加工、稳定性和寿命、老化和厚度依赖性。我们讨论了从材料化学到溶液处理和后处理的问题，展示了这如何导致增强的光伏特性。特别注意通过溶液处理控制分子构型，这会对固态光敏层的结构产生显着影响。简要讨论了主要挑战，包括非富勒烯 OPV 的绿色溶剂加工、稳定性和寿命、老化和厚度依赖性。