Synthesis and Photoluminescence Modulation of Cs 4 Cd 1- x Mn x Bi 2 Cl 12 -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 CsCdCl 3 and Cs 3 Bi 2 Cl 9 were synthesized by the coprecipitation method, and a two-dimensional layered double perovskite Cs 4 CdBi 2 Cl 12 was readily synthesized by mixing the two halide perovskites. We doped different amounts of Mn 2+ into CsCdCl 3 to form CsCd 1- x Mn x Cl 3 , which introduced impurity states into the energy level and exhibited an orange-red light emission that is characteristic of Mn 2+ . A series of 2D layered double perovskites Cs 4 Cd 1- x Mn x Bi 2 Cl 12 were synthesized from CsCd 1- x Mn x Cl 3 and Cs 3 Bi 2 Cl 9 , which showed a bright orange-yellow luminescence under ultraviolet excitation. The presence of high concentrations of Cd 2+ 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.