Optimizing Energy Transfer: Suppressing Cs₂ZnCl₄ Self‐Trapped States and Boosting Ce³⁺ Ion Luminescence Efficiency

Abstract

Incorporating trivalent cerium ions (Ce3+) into colloidal semiconductor nanomaterials, such as zinc sulfide (ZnS) and cesium lead chloride (CsPbCl3), provides a feasible approach for achieving significant Ce3+ photoluminescence (PL). However, due to inefficient intersystem crossing and intense non‐radiative decay of host phosphors, most Ce3+‐doped luminophores exhibit low luminescence efficiency, with photoluminescence quantum yield (PLQY) typically <50%. Additionally, these doping systems often encounter challenges with spectral impurity due to unwanted fluorescence emanating from the host material. In this study, an optimal cesium zinc chloride (Cs2ZnCl4) nanorod (NR) host matrix is meticulously engineered, that significantly enhances the luminescence of Ce3+ ions, reaching a PLQY near unity. Furthermore, these NRs display an exceptionally pure Ce3+ emission spectrum, free from any extraneous emission from the matrix itself. The results from transient absorption and emission experiments reveal a ≈100% energy transfer efficiency from Cs2ZnCl4 to Ce3+, coupled with a significant reduction in radiative self‐trapped states within the host.