Li-TFSI is the most common p-dopant for the hole conductor spiro-MeOTAD in the normal structure (n–i–p) of perovskite solar cells (PSCs), which consistently yield the highest power conversion efficiency (PCE) albeit at the risk of lower long-term operational stability. Here we successfully replace conventional Li-TFSI with Zn-TFSI₂, which not only acts as a highly effective p-dopant but also enhances considerably both the photovoltaic performance and long-term stability. The incorporation of Zn-TFSI₂ as a dopant for spiro-MeOTAD leads to an increase by one order in the hole mobility compared to Li-TFSI from 3.78 × 10⁻³ cm² V⁻¹ s⁻¹ to 3.83 × 10⁻² cm² V⁻¹ s⁻¹. Furthermore, the device with Zn-TFSI₂ showed an 80 mV higher built-in voltage and a bigger recombination resistance than the one with Li-TFSI, which were responsible for the striking increase in both the open-circuit voltage and fill factor, leading to a stabilized PCE of 22.0% for the best cells. Remarkably, the device employing Zn-TFSI₂ demonstrated superb photo-stability, showing even a 2% increase in the PCE after 600 h light soaking at the maximum power point (mpp) under full sun, while the PCE of the device with Li-TFSI decreased by 20% under the same conditions. Similarly, the device with Zn-TFSI₂ showed better operational stability at 50 °C resulting in a 21% decrease in the PCE after 100 h aging at the mpp under full sun while the Li-TFSI based one showed a 55% decrease. Moreover, the Zn-TFSI₂ based device was capable of effectively resisting humidity compared to the one based on Li-TFSI from shelf stability monitoring (R.H. ≥ 40%) in the dark.

中文翻译：

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面向高效，稳定钙钛矿太阳能电池的新型p型掺杂剂†

Li-TFSI是钙钛矿型太阳能电池（PSC）正常结构（n–i–p）中最常见的空穴导体spiro-MeOTAD的p型掺杂物，尽管在这种情况下始终产生最高的功率转换效率（PCE）。长期运行稳定性降低的风险。在这里，我们成功地用Zn-TFSI ₂代替了传统的Li-TFSI ，它不仅可以用作高效的p型掺杂剂，而且还可以显着提高光伏性能和长期稳定性。与Li-TFSI相比，掺入Zn-TFSI ₂作为spiro-MeOTAD的掺杂剂导致空穴迁移率从3.78×10 ^-3 cm ² V ^-1 s ^-1增加到3.83×10 ^-2厘米² V ^-1 s ^-1。此外，具有Zn-TFSI ₂的器件显示出比内置Li-TFSI的器件高80 mV的内置电压和更大的复合电阻，这是导致开路电压和填充因子显着增加的原因，最佳电池的稳定PCE为22.0％。值得注意的是，采用Zn-TFSI ₂的器件表现出了极好的光稳定性，在充满阳光的情况下，在最大功率点（mpp）浸泡600小时后，PCE的PCE甚至提高了2％，而采用Li-在相同条件下，TFSI下降了20％。同样，具有Zn-TFSI ₂的器件在50°C时表现出更好的操作稳定性，在mpp下在全日照下老化100 h后，PCE降低了21％，而基于Li-TFSI的PCE则降低了55％。此外，与基于Li-TFSI的器件相比，基于Zn-TFSI ₂的器件在黑暗中的储藏稳定性监测（RH≥40％）能够有效抵抗潮气。