Warm white-light emitting silica films prepared using lead-free double perovskite QDs

Lead-free double perovskite has attracted widespread attention due to its good stability and non-toxicity. In this work, Cs2AgxNa1−xInCl6 quantum dots were synthesized via a thermal injection method using non-toxic precursors. Based on the wide spectrum of self-bound excitons, the quantum dots achieved white light emission. Bi-doped Cs2AgxNa1−xInCl6 quantum dots with excellent luminescence performance have the same cubic structure, and they have a larger Stokes shift. The cubic perovskite space group is Fmm, and [NaCl6], [AgCl6] and [InCl6] octahedrons alternately appear in the cubic structure. The photoluminescence quantum yield of Cs2AgxNa1−xInCl6 is improved by doping with a small amount of Bi; the PL QY increased to 57.3% with an obvious emission peak at 600 nm. The stability and luminescence intensity of perovskite QDs were further enhanced by SiO2 coating and a Cs2AgxNa1−xInCl6:Bi-SiO2 thin film was prepared using perhydropolysilazane as the precursor. The materials have huge application potential in the field of white light emission and display.