This can be accessed by synthesizing complete device architecture followed by a Focused Ion Beam (FIB) cross section lamella preparation. The FIB procedure often necessitates the addition of protective layers, usually Carbon and the deposition of Platinum (Pt), on top of the selected area of the analysed sample . Unless performed with extreme caution this procedure could be highly damaging, both physically and chemically, especially for perovskite samples,, resulting in inaccurate results. Figure (a) schematically represents the different steps involved cross-section lamella sample preparation by FIB milling technique. Furthermore, for interface studies, the lamella should be mounted onto an appropriate grid such that it is perpendicular to the incoming x-rays. Large angles while mounting the samples could imply a convoluted result that is not a fair representation of the interface. In order to obtain statistically relevant information from STXM, it is recommended to have the width of the active layer as well as the top layer larger than those in a device prepared for application. This would imply that more "pixels" are available for relevant data analysis. In section II analysis of a FIB lamella of FAMAPbI3 has been presented wherein this precaution was not taken.