“…Generally, the inorganic network is viewed as the major contribution to most properties of materials, while various organic cations could result in completely different properties as well . It was demonstrated that designing an organic cation is an effective way to endow the 2D perovskites with different properties. , So far, various single-cation copper-based perovskites (such as methyl, butyl, and hexyl ammonium cations) with different chemical compositions (e.g., ratios of halogen elements) and crystal structures (monoclinic, orthorhombic, hexagonal, etc. ) , have been reported.…”