Efficient Emission in Halide Layered Double Perovskites: The Role of Sb3+ Substitution in Cs4Cd1- xMnxBi2Cl12 Phosphors

Abstract

Layered double perovskites have the potential to further expand the vast space of optoelectronic properties and applications of halide perovskites. Among the ∼60 known members, to date only the ⟨111⟩-oriented layered double perovskites, Cs₄Cd_1-xMn_xBi₂Cl₁₂, have shown efficient photoluminescence (PL). The replacement of Bi with Sb in these materials was investigated, resulting in two new families of layered inorganic perovskite alloys with full solubility. The first, Cs₄Cd_1-xMn_xSb₂Cl₁₂, exhibits a PL emission at 605 nm ascribed to Mn²⁺ centers, with a maximum quantum yield of 28.5%. The second, Cs₄Cd_0.8Mn_0.2(Sb_1-yBi_y)₂Cl₁₂, contains a fixed amount of Mn²⁺ and Cd²⁺ but variable Sb³⁺ and Bi³⁺ concentrations. We observed a decreased efficiency of the Cs₄Cd_1-xMn_xSb₂Cl₁₂ family compared to that of Cs₄Cd_1-xMn_xBi₂Cl₁₂, which was attributed to a decreased spin-orbit and Jahn-Teller couplings in Sb and the subsequent increased electronic delocalization. The present work lays out a roadmap to achieve high photoluminescence efficiencies in layered double perovskites.