Comment on "Copper-Substituted Lead Perovskite Materials Constructed with Different Halides for Working...

In recent years, two-dimensional perovskites have received considerable attention for their potential applications for optoelectronics. Contrary to previous publications, we demonstrate that (CH₃NH₃)₂CuCl₄ hybrid organic-inorganic layered perovskite does not show any room-temperature photoluminescence (PL) under UV excitation. This statement can be extended to other perovskites with general formula AMX₃ or A₂MX₄, based on M: Cu²⁺ and X: Cl^- or Br^-. These materials, the object of increasing interest because of their efficient light absorption in a wide UV-vis-NIR range ideal for solar cells and optoelectronics, lack PL at room temperature, in contrast to recent findings reporting PL properties in this and other similar Cu²⁺-related materials.