How SnF2 Impacts the Material Properties of Lead-Free Tin Perovskites
How SnF2 Impacts the Material Properties of Lead-Free Tin Perovskites
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DOI：
10.1021/acs.jpcc.8b01045
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发表时间：
2018-06-28
影响因子：
3.7
通讯作者：
Hodes, Gary
中科院分区：
文献类型：
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作者：
Gupta, Satyajit;Cahen, David;Hodes, Gary
铅基卤化物钙钛矿（APbX（3））是一种极具吸引力的光电材料。由于Pb的毒性问题，研究了基于Sn的卤化物钙钛矿作为替代物，尽管研究较少。添加SnF 2通常改善锡卤化物钙钛矿基器件的性质。这种效应通常归因于抑制Sn 2 + -> Sn 4+氧化和/或降低Sn空位浓度。这些效应会改变掺杂，有时是相反的方向。在这里，我们回顾了在形成ASnX（3）层的过程中添加SnF 2的影响，如不同的小组所观察到的，既对层本身的性质，也对由这些层制成的光伏电池。SnF 2可以影响ASnX（3）钙钛矿的许多不同性质，包括膜形态、掺杂、对不需要的晶相的形成的控制、对各种因素的材料稳定性以及能级位置。它还（通常）改善了用这些层制成的光伏电池的性能。除了关注所有这些问题之外，我们还描述了钙钛矿的可能掺杂方案，包括一些似乎以前没有考虑过的方案，并得出结论，掺杂机制强烈依赖于Sn 2+氧化成Sn 2+是否发生在材料制备期间或形成膜之后，以及是否涉及氧。
Lead-based halide perovskites (APbX(3)) are fascinating optoelectronic materials. Because of toxicity issues of Pb, Sn-based halide perovskites are studied, although less so, as an alternative. Adding SnF2 often improves the properties of Sn halide perovskite-based devices. This effect is usually ascribed to suppression of Sn2+ -> Sn4+ oxidation and/or decreased Sn vacancy concentration. These effects will change the doping, sometimes in opposite directions. Here we review the effect of addition of SnF2 during the formation of ASnX(3) layers as observed by different groups, both to the properties of the layers themselves and to photovoltaic cells made from these layers. SnF2 can affect many different properties of the ASnX(3) perovskites, including film morphology, doping, control over formation of unwanted crystal phases, material stability to various factors, and energy level positions. It also improves (in general) the performance of photovoltaic cells made with these layers. Besides focusing on all these issues, we also describe possible doping scenarios for the perovskites, including some that do not appear to have been considered before and conclude that the doping mechanism depends strongly on whether the oxidation of Sn2+ to Sn2+ occurs during the materials preparation or after the film is formed, and if oxygen is involved.