Kaiser Waldemar, Ricciarelli Damiano, Mosconi Edoardo, Alothman Asma A, Ambrosio Francesco, De Angelis Filippo
Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), Via Elce di Sotto 8, 06123 Perugia, Italy.
Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
J Phys Chem Lett. 2022 Mar 17;13(10):2321-2329. doi: 10.1021/acs.jpclett.2c00273. Epub 2022 Mar 4.
Tin-halide perovskites (THPs) have emerged as promising lead-free perovskites for photovoltaics and photocatalysis applications but still fall short in terms of stability and efficiency with respect to their lead-based counterpart. A detailed understanding of the degradation mechanism of THPs in a water environment is missing. This Letter presents molecular dynamics (AIMD) simulations to unravel atomistic details of THP/water interfaces comparing methylammonium tin iodide, MASnI, with the lead-based MAPbI. Our results reveal facile solvation of surface tin-iodine bonds in MASnI, while MAPbI remains more robust to degradation despite a larger amount of adsorbed water molecules. Additional AIMD simulations on dimethylammonium tin bromide, DMASnBr, investigate the origins of their unprecedented water stability. Our results indicate the presence of amorphous surface layers of hydrated zero-dimensional SnBr complexes which may protect the inner structure from degradation and explain their success as photocatalysts. We believe that the atomistic details of the mechanisms affecting THP (in-)stability may inspire new strategies to stabilize THPs.
卤化锡钙钛矿（THPs）已成为用于光伏和光催化应用的有前景的无铅钙钛矿，但在稳定性和效率方面仍不及基于铅的同类产品。目前尚缺乏对THPs在水环境中降解机制的详细了解。本文通过分子动力学（AIMD）模拟，揭示了甲基碘化锡铵（MASnI）与基于铅的MAPbI相比，THP/水界面的原子细节。我们的结果表明，MASnI表面的锡-碘键易于溶剂化，而尽管吸附了大量水分子，MAPbI对降解的耐受性更强。对二甲基溴化锡铵（DMASnBr）的额外AIMD模拟研究了其前所未有的水稳定性的来源。我们的结果表明存在水合零维SnBr络合物的非晶表面层，这可能保护内部结构不被降解，并解释了它们作为光催化剂的成功之处。我们相信，影响THP稳定性的机制的原子细节可能会激发稳定THP的新策略。
