Manganese incorporation for cesium zinc chloride crystals and the resultant structural, and optical characteristics

Here, we have successfully synthesized manganese (Mn) doped cesium zinc chloride (Cs2ZnCl4) crystals for the first time by a simple solvothermal method, which alters the optical properties due to the structural transformation. When Mn2+ feeding ratio x is lower than 0.4, tetrahedral structure of Cs2ZnCl4 crystals is dominant with green emission of Mn2+ doping, but both tetrahedral and octahedral structure show green-red emission when Mn2+ feeding ratio exceeds 0.4. Combining experimental analysis and density functional theory (DFT) calculations, different energy transfer pathways and photoluminescence (PL) emission are revealed. When the host lattice crystal field surroundings of tetrahedral coordination, due to the incorporation of Mn2+, the exciton relaxes to 4T1 and then transitions to 6A1. However, when the host lattice crystal field surroundings have a strong ligand field strength, the excitons are more advantageously confined to the octahedron. Our work provides deeper insights into the structural transformation of zero-dimensional cesium zinc chloride due to the Mn2+ incorporation from doping to substitution of B site.