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

Abstract

Lead-free double perovskite has attracted widespread attention due to its good stability and non-toxicity. In this work, Cs₂Ag_xNa_1−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 Cs₂Ag_xNa_1−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 Cs₂Ag_xNa_1−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 Cs₂Ag_xNa_1−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.