Modulating luminescence of K3AlF6:Mn4+ NCs via charge compensation and localized surface plasmon resonance effect

The reduction in photoluminescence efficiency due to crystallite downsizing is a significant issue in Mn 4+ -doped fluoride nanomaterials, crucial for their application in full-color micro-LED displays. This study presents a strategy to enhance the photoluminescence efficiency of K 3 AlF 6 :Mn 4+ nanocrystals (NCs) by incorporating Mg 2+ for charge compensation and utilizing the plasmonic effect of Au nanorods. We found that Mg 2+ incorporation effectively reduced lattice defects, increasing photoluminescence intensity by 17% and internal quantum efficiency from 22.37% to 27.56%. Fabricating Au@SiO 2 /fluoride nanocomposites, we investigated how the SiO 2 spacer layer thickness, Au@SiO 2 resonance wavelength, and relative concentration affect photoluminescence properties. Optimizing the balance between Purcell and Förster resonance energy transfer effects further increased photoluminescence intensity by 25%, internal quantum efficiency to 32.09%, and external quantum efficiency from 14.20% to 18.05%. Additionally, we assessed the potential application of these nanocomposites in micro-LED display technology by examining nanocomposite-PMMA films. This work provides insights into the development of highly efficient red-emitting nanomaterials.