“…However, the toxicity of Pb severely hampers its commercial application in optoelectronics. Therefore, the selection of low-toxicity or nontoxic ions, such as Bi 3+ , In 3+ , Sb 3+ , Sn 2+ , Cu + , and Ag + , is preferred for the substitution of Pb 2+ ions. , Thus, a number of lead-free and stable perovskite materials have garnered significant interest, showcasing optoelectronic properties analogous to those of lead-based perovskites. In particular, one monovalent cation and one trivalent cation to replace two toxicity of Pb 2+ form an eco-friendly stable double perovskite with self-trapped exciton photoluminescence, which exhibits excellent optoelectronic properties, including a broad emission spectrum, large Stokes-Shift, low band gap, and tunable emission wavelength .…”