Cesium Copper Halide (Cs3Cu2X5, X=Cl, Br, I) Perovskite Nanocrystals: A Potential Candidate in Lead-Free Metal Halide Perovskite Nanomaterials

All-inorganic lead-free halide perovskite nanomaterials are extensively analyzed in the recent years for several kind of optoelectronic applications. Because of their less toxic and high stability, the structural and optical properties are much investigated and proposed with new concepts. Out of others, all-inorganic cesium copper halide perovskite nanomaterials (Cs3Cu2X5 where X=Cl, Br, and I) have emerged as potential candidate for the modern generation optoelectronic device structures. These nanomaterials can be prepared through colloidal route and applied as films through solvent-based deposition approaches. Interesting properties such as large UV light absorption coefficient value, high photoluminescent quantum yield (PLQY), self-trapping exciton (STE), intrinsic defects in the structure are showing that these materials could be a promising candidate for the future generation optoelectronic devices. Single crystals, quantum dots (QDs), two-dimensional (2D) nanostructures and nanorods of these materials are indeed showing excellent progress for further developments in the area of lead-free halide perovskite nanomaterials. This chapter narrates about the present status of Cs3Cu2X5 nanocrystals (NCs), which include discussion about their potential synthetic routes, exciting optical properties, and potential applications.