Compared with inorganic photovoltaics, organic photovoltaics (OPVs) still have a low fill factor (FF) that restricts their power conversion efficiency (PCE). The FF is determined by the resistances that are influenced by carriers recombination. In this work, the tandem structure is demonstrated to be a feasible solution to improve the FF of OPVs. The recombination losses of subcells in the tandem structure are reduced and consequently improves the FF. When the two subcells are stacked in a tandem structure, the highest value of the FF reaches 76.6%, much higher than that of 66.1% achieved by its single junction device. Finally, a PCE of 14.1% with a FF of 73.6% is achieved in a tandem OPV after optimizing the thickness of each active layer. This work not only demonstrates the inherent mechanism for a higher FF in tandem OPVs but also presents a feasible solution for high-performance photovoltaic devices.

中文翻译：

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通过减少电荷重组，以高填充因子实现高效的串联有机光伏

与无机光伏相比，有机光伏（OPV）仍然具有较低的填充因子（FF），这限制了其功率转换效率（PCE）。FF由受载流子重组影响的电阻确定。在这项工作中，串联结构被证明是提高OPV FF的可行解决方案。串联结构中子细胞的重组损失减少，因此提高了FF。当两个子电池以串联结构堆叠时，FF的最大值达到76.6％，远高于其单结器件达到的66.1％。最后，在优化每个有源层的厚度后，在串联式OPV中实现了14.1％的PCE和FF的73.6％。