Solar cells based on metal halide perovskites are one of the most promising photovoltaic technologies1–4. Over the past few years, the long-term operational stability of such devices has been greatly improved by tuning the composition of the perovskites5–9, optimizing the interfaces within the device structures10–13, and using new encapsulation techniques14,15. However, further improvements are required in order to deliver a longer-lasting technology. Ion migration in the perovskite active layer—especially under illumination and heat—is arguably the most difficult aspect to mitigate16–18. Here we incorporate ionic liquids into the perovskite film and thence into positive–intrinsic–negative photovoltaic devices, increasing the device efficiency and markedly improving the long-term device stability. Specifically, we observe a degradation in performance of only around five per cent for the most stable encapsulated device under continuous simulated full-spectrum sunlight for more than 1,800 hours at 70 to 75 degrees Celsius, and estimate that the time required for the device to drop to eighty per cent of its peak performance is about 5,200 hours. Our demonstration of long-term operational, stable solar cells under intense conditions is a key step towards a reliable perovskite photovoltaic technology. Addition of an ionic liquid, BMIMBF4, to metal halide perovskite solar cells improves their efficiency and long-term operation under accelerated aging conditions of high temperature and full-spectrum sunlight.

中文翻译：

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使用离子液体添加剂具有长期稳定性的平面钙钛矿太阳能电池

基于金属卤化物钙钛矿的太阳能电池是最有前途的光伏技术之一1-4。在过去几年中，通过调整钙钛矿的组成 5-9、优化器件结构内的界面 10-13 以及使用新的封装技术 14、15，这些器件的长期运行稳定性得到了极大的提高。但是，需要进一步改进以提供更持久的技术。钙钛矿活性层中的离子迁移——尤其是在光照和加热下——可以说是最难缓解的方面 16-18。在这里，我们将离子液体结合到钙钛矿薄膜中，然后再结合到正-本征-负光伏器件中，提高了器件效率并显着提高了器件的长期稳定性。具体来说，我们观察到最稳定的封装器件在 70 到 75 摄氏度的连续模拟全光谱阳光下超过 1,800 小时的性能下降仅约 5%，并估计该器件所需的时间下降到 80其峰值性能的百分比约为 5,200 小时。我们在强烈条件下展示了长期运行、稳定的太阳能电池，这是迈向可靠的钙钛矿光伏技术的关键一步。在金属卤化物钙钛矿太阳能电池中添加离子液体 BMIMBF4 可提高其在高温和全光谱阳光加速老化条件下的效率和长期运行。800 小时在 70 到 75 摄氏度，并估计设备下降到其峰值性能的 80% 所需的时间约为 5,200 小时。我们在强烈条件下展示了长期运行、稳定的太阳能电池，这是迈向可靠的钙钛矿光伏技术的关键一步。在金属卤化物钙钛矿太阳能电池中添加离子液体 BMIMBF4 可提高其在高温和全光谱阳光加速老化条件下的效率和长期运行。800 小时在 70 到 75 摄氏度，并估计设备下降到其峰值性能的 80% 所需的时间约为 5,200 小时。我们在强烈条件下展示了长期运行、稳定的太阳能电池，这是迈向可靠的钙钛矿光伏技术的关键一步。在金属卤化物钙钛矿太阳能电池中添加离子液体 BMIMBF4 可提高其在高温和全光谱阳光加速老化条件下的效率和长期运行。