CsPb_xMn_1-xCl₃ Perovskite Quantum Dots with High Mn Substitution Ratio

CsPbX₃ (X = Cl, Br, I) perovskite quantum dots (QDs) are potential emitting materials for illumination and display applications, but toxic Pb is not environment- and user-friendly. In this work, we demonstrate the partial replacement of Pb with Mn through phosphine-free hot-injection preparation of CsPb_xMn_1-xCl₃ QDs in colloidal solution. The Mn substitution ratio is up to 46%, and the as-prepared QDs maintain the tetragonal crystalline structure of the CsPbCl₃ host. Meaningfully, Mn substitution greatly enhances the photoluminescence quantum yields of CsPbCl₃ from 5 to 54%. The enhanced emission is attributed to the energy transfer of photoinduced excitons from the CsPbCl₃ host to the doped Mn, which facilitates exciton recombination via a radiative pathway. The intensity and position of this Mn-related emission are also tunable by altering the experimental parameters, such as reaction temperature and the Pb-to-Mn feed ratio. A light-emitting diode (LED) prototype is further fabricated by employing the as-prepared CsPb_xMn_1-xCl₃ QDs as color conversion materials on a commercially available 365 nm GaN LED chip.