Coherent X-ray imaging applied to the study of functional materials

Abstract

This master's project aims to implement the ptychography technique, which consists of imaging with coherent X-rays - without the use of lenses after the sample - by phase recovery. X-ray imaging, under development in modern, state-of-the-art synchrotron light sources, has been able to achieve a resolution of the order of tens of nanometers in a variety of objects of study. A methodological study of the technique will be carried out in the LNLS SXS beamline in order to prepare the background for its intense use in the new SIRIUS light source. The instrumentation and methodology developed during this project will be installed and commissioned, preliminarily at the UVX source in 2018, and later on the CARNAÚBA beamline at SIRIUS in 2019. In addition to the development and commissioning of the instrumentation, an intensive study will be carried out on the algorithms and methods for acquisition and data processing for image reconstruction. The first X-ray experiments will be carried out to study photovoltaic materials based on hybrid perovskites, a material of high technological value. These materials have a close relationship between photovoltaic property, film morphology and elemental segregation effect. These effects are on an interesting scale - sub-micrometric, with granulometry varying from 400 to 800 nm - for the development of the technique. A simultaneous experiment of elemental mapping - by X-ray fluorescence - mapping of the X-ray excited luminescence optical activity - XEOL - and X-ray ptychography will allow to find the correlation between morphological, chemical composition and optical properties of the material, opening wide possibilities of applications in several other systems.