Clusters of Cesium–Lead–Iodide Perovskites in the Zeolite Matrix

Small clusters of cesium–lead–iodide perovskites (CLIPs) have been prepared in the Na–X zeolite matrix and studied by means of spectroscopy and quantum chemical modeling. Regularity of pores in single crystals of zeolite assures the formation of clusters of a certain size. By the first-principles quantum chemical calculations, we have determined that clusters Cs₄PbI₆, Cs₅Pb₂I₉, and probably Cs₇Pb₅I₁₆ with a size of 0.74, 1.29, and 1.36 nm, respectively, have elevated stability compared to other species, and they fit into the pores of Na–X zeolite. Electronic energy spectra of these clusters have been calculated and compared with experimentally measured ones.