Methodologies for structural investigations of organic lead halide perovskites

Fundamentally, organic lead halide perovskites (OLHPs), which have attracted tremendous attention in the field of photovoltaic technology, are the materials organized in the platform of a perovskite structure by hybridizing the organic component with the inorganic lead halide. In understanding the highly efficient photovoltaic performance of perovskite solar cells (PSCs), crystallographic investigation of OLHPs has been an accompanying field of study because opto-electronic properties are believed to be closely related to their crystal structure. This article reviews the progress of the structural investigations of OLHPs. Macro-scale structural analyses, including X-ray diffraction, are discussed to introduce the investigation methods for the overall properties of OLHPs. Subsequently, the progresses of the microstructural investigations, such as transmission electron microscopy, are described to understand the situation of the micro-scale crystallographic approaches that were achieved recently. In addition, electron damages, which are the obstacles for the structural investigation of OLHPs in electron microscopy, are discussed, and the methodologies alleviating the electron damages are introduced. Based on this review, we believe that the advances in structural investigations are crucial for further advancements in the research on the OLHPs for PSCs and related applications.