Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells.
Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells.
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DOI：
10.1038/ncomms15218
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发表时间：
2017-05-11
影响因子：
16.6
通讯作者：
Haque SA
中科院分区：
文献类型：
--
作者：
Aristidou N;Eames C;Sanchez-Molina I;Bu X;Kosco J;Islam MS;Haque SA
甲基铵卤化铅钙钛矿作为下一代太阳能电池的有前途的材料吸引了人们的强烈兴趣，但与长期稳定性相关的严重问题需要解决。基于CH3NH3PbI3的Peroxides膜在暴露于氧气和光时经历快速降解。在这里，我们报告机械的见解，这种氧诱导的光降解从一系列的实验和计算技术。我们发现，快速的氧气扩散到CH3NH3PbI3薄膜伴随着光诱导形成的高活性的超氧物种。由小晶粒组成的过氧化氢膜具有较高的超氧化物产率和较低的稳定性。从头算模拟表明，碘空位是介导光诱导形成的超氧物种从氧的首选网站。用碘化物盐的薄膜钝化显示出增强膜和器件稳定性。从这项研究中获得的降解现象的理解是重要的稳定的钙钛矿太阳能电池的未来设计和优化。确定卤化铅钙钛矿的降解途径是其发展为可行的太阳能技术的关键。Aristidou等人将碘空位确定为介导由嵌入氧光诱导形成超氧化物物种的优选位点。
Methylammonium lead halide perovskites are attracting intense interest as promising materials for next-generation solar cells, but serious issues related to long-term stability need to be addressed. Perovskite films based on CH3NH3PbI3 undergo rapid degradation when exposed to oxygen and light. Here, we report mechanistic insights into this oxygen-induced photodegradation from a range of experimental and computational techniques. We find fast oxygen diffusion into CH3NH3PbI3 films is accompanied by photo-induced formation of highly reactive superoxide species. Perovskite films composed of small crystallites show higher yields of superoxide and lower stability. Ab initio simulations indicate that iodide vacancies are the preferred sites in mediating the photo-induced formation of superoxide species from oxygen. Thin-film passivation with iodide salts is shown to enhance film and device stability. The understanding of degradation phenomena gained from this study is important for the future design and optimization of stable perovskite solar cells. Determining the degradation pathways in lead halide perovskites is key to its development as a viable solar technology. Aristidou et al. identify iodide vacancies as the preferred sites in mediating the photo-induced formation of superoxide species from intercalated oxygen.