Clarendon Laboratory, University of Oxford, Oxford, UK.
Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden.
Nature. 2019 Jul;571(7764):245-250. doi: 10.1038/s41586-019-1357-2. Epub 2019 Jul 10.
Solar cells based on metal halide perovskites are one of the most promising photovoltaic technologies. Over the past few years, the long-term operational stability of such devices has been greatly improved by tuning the composition of the perovskites, optimizing the interfaces within the device structures, and using new encapsulation techniques. 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 mitigate. 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.
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。在过去的几年中，通过调整钙钛矿的组成、优化器件结构内的界面以及使用新的封装技术，大大提高了此类器件的长期运行稳定性。然而，为了提供更持久的技术，还需要进一步改进。在钙钛矿活性层中，离子迁移（尤其是在光照和热量下）是最难解决的问题。在这里，我们将离子液体掺入钙钛矿薄膜中，然后掺入正-本征-负光伏器件中，从而提高了器件效率，并显著改善了器件的长期稳定性。具体来说，我们观察到在 70 至 75 摄氏度下，在持续模拟全光谱阳光照射 1800 小时以上后，最稳定的封装器件的性能仅下降约 5%，估计器件性能下降到其峰值的 80%所需的时间约为 5200 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，这是实现可靠钙钛矿光伏技术的关键一步。
