A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples, due to their typically limited time-stability, and the understanding of the role of external factors that can induce a crystal phase transformation (such as humidity, intense light flux, temperature, etc.). In this perspective, it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring. In this paper we propose Raman spectroscopy as the ideal technique to solve this problem. The vibrational analysis of CsPbI₃ in the α-phase and δ-phase and of the Cs₄PbI₆ secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework. Finally, the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.

钙钛矿型卤化铅的开发中的一个主要问题是评估样品的晶体结构，这是因为它们通常具有有限的时间稳定性，并且要了解可能引起晶体相变（例如湿度）的外部因素的作用。 ，强烈的光通量，温度等）。从这个角度来看，最重要的是要拥有一种快速，可靠的实验工具，该工具能够立即指示出样品的多晶型，并有可能整合原位测量以进行持续监测。在本文中，我们提出拉曼光谱作为解决此问题的理想技术。CsPbI ₃在α相和δ相以及Cs ₄ PbI ₆的振动分析报告了第二相，并通过将相的实验光谱与DFT框架内计算的拉曼模进行比较，指定了所有振动模。最后，使用原位拉曼测量研究了激光诱导相降解的机理，从而提供了有关在此过程中产生的次级相的新见解。