Bækbo Martin J, Hansen Ole, Chorkendorff Ib, Vesborg Peter C K
Surfcat, Technical University of Denmark Fysikvej, Building 312, 2800 Kgs. Lyngby Denmark
Department of Micro- and Nanotechnology, Technical University of Denmark 2800 Kgs. Lyngby Denmark.
RSC Adv. 2018 Aug 23;8(52):29899-29908. doi: 10.1039/c8ra04851g. eCollection 2018 Aug 20.
Methylammonium lead halide perovskites have recently emerged as a very attractive and versatile material for solar cell production. Several different perovskite fabrication methods can be used though most of them involve either spin coating, evaporation under high vacuum or a combination hereof. In this study we focus on thermal evaporation of methylammonium iodide (MAI), or more specifically, why this process, in terms of a physical vapour deposition, requires such a high deposition pressure to be successful. We use quartz crystal micro balance (QCM) measurements as well as mass spectrometry. The results indicate that MAI has a very low sticking especially if the substrate is held at elevated temperatures and is furthermore observed to evaporate with disproportionation into primarily CHNH and HI. Even when PbCl is deposited on the QCM crystal, so that CHNHPbICl perovskite can form, the MAI sticking remains low, possibly due to the requirement that both species be present on the film surface at the same time to form the perovskite. The results provide guidelines for designing a perovskite deposition chamber and additionally fundamental information about MAI evaporation.
甲基铵卤化铅钙钛矿最近已成为一种非常有吸引力且用途广泛的太阳能电池生产材料。虽然可以使用几种不同的钙钛矿制造方法，但大多数方法要么涉及旋涂、高真空蒸发，要么是两者的结合。在本研究中，我们专注于甲基碘化铵（MAI）的热蒸发，或者更具体地说，就物理气相沉积而言，为什么这个过程需要如此高的沉积压力才能成功。我们使用石英晶体微天平（QCM）测量以及质谱分析。结果表明，MAI的附着性非常低，特别是当基板保持在高温时，并且还观察到MAI会歧化蒸发成主要是CHNH和HI。即使将PbCl沉积在QCM晶体上，以便可以形成CHNHPbICl钙钛矿，MAI的附着性仍然很低，这可能是因为形成钙钛矿需要两种物质同时存在于薄膜表面。这些结果为设计钙钛矿沉积腔室提供了指导方针，并额外提供了有关MAI蒸发的基本信息。
