Metal oxide mesocrystals with tailored structures and properties for energy conversion and storage applications

Mesocrystals (MCs) are superstructures with a crystallographically ordered alignment of nanoparticles. Owing to their organized structures, MCs posses some unique characteristics such as a high surface area, pore accessibility, and good electronic conductivity and thermal stability; thus, MCs could be beneficial for many areas of research and application. This review begins with a description of the common synthesis strategies for, and characterization and fundamental properties of metal oxide MCs. Newly developed analytical methods (that is, photoconductive atomic force microscopy and single-molecule, single-particle fluorescence microscopy) for unraveling the charge transport and photocatalytic properties of individual MCs are then introduced. Further, recent developments in the applications of various metal oxide MCs, especially in the fields of energy conversion and storage, are also reviewed. Finally, several perspectives in terms of future research on MCs are highlighted.