The power conversion efficiency (PCE) of state‐of‐the‐art organic solar cells is still limited by significant open‐circuit voltage (V_OC) losses, partly due to the excitonic nature of organic materials and partly due to ill‐designed architectures. Thus, quantifying different contributions of the V_OC losses is of importance to enable further improvements in the performance of organic solar cells. Herein, the spectroscopic and semiconductor device physics approaches are combined to identify and quantify losses from surface recombination and bulk recombination. Several state‐of‐the‐art systems that demonstrate different V_OC losses in their performance are presented. By evaluating the quasi‐Fermi level splitting (QFLS) and the V_OC as a function of the excitation fluence in nonfullerene‐based PM6:Y6, PM6:Y11, and fullerene‐based PPDT2FBT:PCBM devices with different architectures, the voltage losses due to different recombination processes occurring in the active layers, the transport layers, and at the interfaces are assessed. It is found that surface recombination at interfaces in the studied solar cells is negligible, and thus, suppressing the non‐radiative recombination in the active layers is the key factor to enhance the PCE of these devices. This study provides a universal tool to explain and further improve the performance of recently demonstrated high‐open‐circuit‐voltage organic solar cells.

中文翻译：

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量化高效非富勒烯有机太阳能电池的准费米能级分裂和开路电压损失

先进的有机太阳能电池的功率转换效率（PCE）仍然受到明显的开路电压（V _OC）损失的限制，部分原因是有机材料的激子特性，部分原因是结构设计不当。因此，定量的不同贡献V _OC损失是重要的，以使在有机太阳能电池的性能的进一步改进。在本文中，将光谱学和半导体器件物理方法结合起来，以识别和量化表面重组和本体重组造成的损失。几个展示不同V _OC的最新系统列出了它们的性能损失。在具有不同架构的基于非富勒烯的PM6：Y6，PM6：Y11和基于富勒烯的PPDT2FBT：PCBM器件中，通过评估准费米能级分裂（QFLS）和V _OC作为激发通量的函数评估在活性层，传输层和界面处发生的不同重组过程。发现所研究的太阳能电池的界面处的表面复合可以忽略不计，因此，抑制有源层中的非辐射复合是增强这些器件PCE的关键因素。这项研究提供了一种通用工具来解释和进一步改善最近证明的高开路电压有机太阳能电池的性能。