Research of decomposition mechanism of mixed cation-anionic metal halide perovskite material

在2022财年，这位研究员参与了几个研究项目，并指导了两名博士生。特别是，她参与了三个项目：第一个项目侧重于使用苯基卤化铵分子钝化钙钛矿层，目的是了解这些分子在钙钛矿表面的机理，特别是考虑到不同的钙钛矿组成和不同卤化物(碘、溴和氯)的影响。事实上，文献中众所周知，这些钝化分子既改善了稳定性，又改善了器件性能，但对于其化学机制还没有达成一致意见。第二个项目致力于为常用的自组装分子(2PACz)开发新的沉积方法，这种分子在p-i-n器件结构中用作空穴传输材料。这通常是旋涂的，这种沉积方法已被证明在制造高性能器件方面是有效的，但不允许在大面积器件上均匀覆盖。因此，我们发现可以采用其他的沉积方法，例如热蒸发和喷涂层技术，与传统的旋涂方法相比，后者对于高甚至更高的器件性能特别有效。他也尝试制作大面积的器件(面积22.4平方厘米)，但由于难以在大面积上沉积部分器件，控制器件的性能仍然很低。第三个项目处于早期阶段，涉及用作自组装分子的新的电子传输分子。

In FY2022 the fellow worked on several research projects and supervised two PhD students. In particular, she worked on three projects: the first focuses on the passivation of the perovskite layer using phenethyl ammonium-halide molecules with the aim to understand the mechanism of these molecules on the perovskite surface, specifically taking into account different perovskite compositions and the effect of different halides (iodine, bromine and chlorine). It is in fact well known in literature that these passivation molecules improve both stability and device performance, but there is no unanimous agreement on the chemical mechanism. The second project focuses on developing new deposition methods for the commonly used self-assembly molecule (2PACz), used as hole transporting material in p-i-n device configuration. This is usually spin-coated and this deposition methos has shown to be effective in making high performing devices but does not allow a uniform coverage on large area devices. We therefore show that alternative deposition methods can be employed, such as thermal evaporation and spray-coating techniques, with the latter being particularly effective for high or even higher device performances compared to the traditional spin-coating method. The fellow also tried to fabricate large area devices (area 22.4cm2) but the performances of control devices remain low due to difficulties in depositing part of the device on large area. The third project is at early stages and involves new electron transporting molecules to be used as self-assembly molecules.