Rare-earth single atom based luminescent composite nanomaterials: Tunable full-color single phosphor and applications in WLEDs

High-quality single-component white phosphors are instrumental in realizing high-efficiency devices. Rare earth fluorides and carbon quantum dots have great potential in the white light-emitting diode (WLED) field due to their unique advantages. Here, Rare-earth single atom based NaGdF₄:Tb³⁺/Eu³⁺@C:N/Eu³⁺ single phosphor with tunable full-color luminescence was reported. The results of density functional theory (DFT) calculation and experimental characterization show that C atoms cannot be replaced by Eu³⁺, but C atoms are more favorable for anchoring Eu³⁺ single atoms. The DFT was employed to optimize the structures of the C:N/Eu³⁺ and NaGdF₄:Tb³⁺/Eu³⁺, and calculate the work function, optical properties, and charge density difference. The obtained tunable full-color single phosphor can emit stable light from blue to red or even white. The constructed WLED devices also have stable and excellent color performance, that is, a color rendering index of up to 95 and a lower color temperature, and it has broad application possibilities in WLEDs.