Department of Chemistry, University of Saskatchewan , 110 Science Place, Saskatoon, SK Canada , S7N 5C9.
ACS Nano. 2015 Feb 24;9(2):1955-63. doi: 10.1021/nn506864k. Epub 2015 Feb 9.
Perovskite solar cells have rapidly advanced to the forefront of solution-processable photovoltaic devices, but the CH3NH3PbI3 semiconductor decomposes rapidly in moist air, limiting their commercial utility. In this work, we report a quantitative and systematic investigation of perovskite degradation processes. By carefully controlling the relative humidity of an environmental chamber and using in situ absorption spectroscopy and in situ grazing incidence X-ray diffraction to monitor phase changes in perovskite degradation process, we demonstrate the formation of a hydrated intermediate containing isolated PbI6(4-) octahedra as the first step of the degradation mechanism. We also show that the identity of the hole transport layer can have a dramatic impact on the stability of the underlying perovskite film, suggesting a route toward perovskite solar cells with long device lifetimes and a resistance to humidity.
钙钛矿太阳能电池已迅速成为溶液处理型光伏器件的前沿领域，但 CH3NH3PbI3 半导体在潮湿空气中会迅速分解，限制了其商业应用。在这项工作中，我们报告了对钙钛矿降解过程的定量和系统研究。通过仔细控制环境室的相对湿度，并使用原位吸收光谱和原位掠入射 X 射线衍射来监测钙钛矿降解过程中的相变化，我们证明了含有孤立 PbI6(4-)八面体的水合中间相的形成是降解机制的第一步。我们还表明，空穴传输层的性质会对底层钙钛矿薄膜的稳定性产生巨大影响，这为实现具有长器件寿命和抗湿性的钙钛矿太阳能电池提供了一种途径。
