Organic photovoltaics (OPVs) have a promising future in reliable energy harvesting to drive low power consumption devices for indoor applications. In this article, the outdoor (1 sun) and indoor (2700 K LED) performance of an inverted OPV, PTB7-Th:PC₇₀BM, with three different solution-processed electron transport layers (ETLs = PFN, TiO_x, and ZnO) was compared. The morphological, optical, and electrical measurements indicated the strong dependency of the OPV performance on the illumination conditions. The sample with PFN-ETL showed the highest outdoor performance with a power conversion efficiency (PCE) of 10.55% and the best reported fill factor (FF) of 75.00% among the PTB7-Th:PC₇₀BM-based OPVs; surprisingly, it exhibited the lowest performance when illuminated under 250–2000 lux 2700 K LED light. Meanwhile, the lowest outdoor performance was demonstrated by ZnO with a PCE of 10.03%; it displayed the best indoor performance with a PCE of 13.94% under 1000 lux LED light and a PCE of up to 16.49% under 1750 lux LED light. The changes in the FF values could be estimated by incorporating the parasitic resistance effect due to the type of ETL used. Additionally, using impedance spectroscopy, we observed that the indoor performance agreed well with the trend of the charge collection efficiency.

中文翻译：

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用于全面研究有机光伏室内性能的阴极界面工程方法

有机光伏（OPV）在可靠的能量收集方面具有广阔的前景，以驱动室内应用的低功耗设备。在本文中，具有三个不同溶液处理的电子传输层（ETLs = PFN，TiO _x和ZnO ）的反向OPV PTB7-Th：PC ₇₀ BM的室外（1个阳光）和室内（2700 K LED）性能）进行了比较。形态，光学和电学测量表明OPV性能对照明条件的强烈依赖性。在PTB7-Th：PC _70中，具有PFN-ETL的样品表现出最高的户外性能，功率转换效率（PCE）为10.55％，最佳报告的填充因子（FF）为75.00％。基于BM的OPV；令人惊讶的是，在250–2000 lux 2700 K LED照明下，它表现出最低的性能。同时，ZnO的户外性能最低，其PCE为10.03％。它显示出最佳的室内性能，在1000 lux LED灯下的PCE为13.94％，在1750 lux LED灯下的PCE最高为16.49％。FF值的变化可以通过合并由于使用的ETL类型引起的寄生电阻效应来估算。此外，使用阻抗谱，我们观察到室内性能与电荷收集效率的趋势非常吻合。