Adjustment of the composition, structure, and properties of a lead-free layered double perovskite

In recent years, due to the toxicity and instability of halide lead-based perovskites, the search for alternatives that retain the superior optoelectronic performance of halide lead-based perovskite materials while being non-toxic and stable has gradually become an important research topic. Among them, the lead-free perovskites with the general formula A(4)M(II)M(2)(III)X(12) are very promising in solving the problem of lead ion toxicity. Here, we have studied the Cs4CuSb2Cl12 perovskite material, which is a three-layer (n = 3) perovskite structure oriented along <111>. In this paper, a series of Cs4Cu1-xCdxSb2Cl12 (0 <= x <= 1) and Cs4Cu1-yMnySb2Cl12 (0 <= y <= 1) microcrystals were synthesized. By varying the value of x and y, we successfully tuned the bandgap and optical properties of Cs4CuSb2Cl12. This allowed us to establish a clear correlation between the material's composition, structure, and properties, laying the foundation for further research and application of Cs4CuSb2Cl12 materials.