Long-term stability remains a key issue impeding the commercialization of halide perovskite solar cells (HPVKSCs). The diffusion of molecules and ions causes irreversible degradation to photovoltaic device performance. Here, we demonstrate a facile strategy for producing highly stable HPVKSCs by using a thin but compact semimetal Bismuth interlayer. The Bismuth film acts as a robust permeation barrier that both insulates the perovskite from intrusion by undesirable external moisture and protects the metal electrode from iodine corrosion. The Bismuth-interlayer-based devices exhibit greatly improved stability when subjected to humidity, thermal and light stresses. The unencapsulated device retains 88% of its initial efficiency in ambient air in the dark for over 6000 h; the devices maintain 95% and 97% of their initial efficiencies after 85 °C thermal aging and light soaking in nitrogen atmosphere for 500 h, respectively. These sound stability parameters are among the best for planar structured HPVKSCs reported to date.

长期稳定性仍然是阻碍卤化物钙钛矿太阳能电池（HPVKSC）商业化的关键问题。分子和离子的扩散导致光伏器件性能不可逆地退化。在这里，我们展示了一种通过使用薄而致密的半金属铋中间层来生产高度稳定的HPVKSC的简便策略。铋膜充当坚固的渗透屏障，既可以使钙钛矿免受不良外部湿气的侵入，又可以保护金属电极免受碘腐蚀。当受到湿度、热和光应力时，基于铋夹层的器件表现出大大提高的稳定性。未封装的器件在黑暗环境空气中 6000 小时以上仍保持其初始效率的 88%；在 85°C 热老化和氮气气氛中光浸泡 500 小时后，器件分别保持了初始效率的 95% 和 97%。这些声音稳定性参数是迄今为止报道的平面结构 HPKSC 的最佳参数之一。