Synthesis and Photoluminescence Modulation of Cs4Cd1–xMnxBi2Cl12-Based Two-Dimensional Layered Double Perovskites

Two-dimensional (2D) layered double perovskites have attracted much attention because of their excellent photoelectric properties. However, few reports have been published on the synthesis of 2D layered double perovskites from halide perovskites as precursors. Here, we report that CsCdCl3 and Cs3Bi2Cl9 were synthesized by the coprecipitation method, and a two-dimensional layered double perovskite Cs4CdBi2Cl12 was readily synthesized by mixing the two halide perovskites. We doped different amounts of Mn2+ into CsCdCl3 to form CsCd1-xMnxCl3, which introduced impurity states into the energy level and exhibited an orange-red light emission that is characteristic of Mn2+. A series of 2D layered double perovskites Cs4Cd1-xMnxBi2Cl12 were synthesized from CsCd1-xMnxCl3 and Cs3Bi2Cl9, which showed a bright orange-yellow luminescence under ultraviolet excitation. The presence of high concentrations of Cd2+ in the two-dimensional layered double perovskites weakened the strong Mn-Mn coupling and suppressed the energy transfer to defects, thus minimizing nonradiative decay and promoting efficient energy transfer. Our work provides a new concept for the synthesis of low-dimensional metal halide perovskites with unique optical properties.