X-ray diffraction and Raman spectroscopy for lead halide perovskites

Lead halide perovskites (LHPs) have recently emerged as promising materials for solar energy conversions. Here, the underlying optoelectronic properties, charge transport abilities, energy level positions for alignment of contact materials, and the stability of LHPs are all dependence on the material composition and structure. Therefore, understanding the structure-to-property relationships is crucial from both a fundamental perspective as well as for constructing efficient and stable devices based on LHPs. XRD is a century old powerful tool to extract the structure of crystalline materials. It provides means to quantify atomic level distances, extraction of symmetries, densities, compositional and temperature dependent phase transitions as well as orientation and size of crystallites in polycrystalline films. Raman spectroscopy is a versatile characterization technique that provides information about the chemical composition and phases in crystalline materials, as well as the local vibration found in amorphous structures, molecular materials, solvents, and gases. With this knowledge, one can extract chemical identities via observed vibrations, bonding interactions, orientations, symmetries, local and lattice vibrations in a crystalline materials. In this contribution, we succinctly discuss the latest progress in understanding the physical properties of LHPs using XRD and Raman Spectroscopy.