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:Tb^(3+)/Eu^(3+)@C:N/Eu^(3+)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 Eu^(3+),but C atoms are more favorable for anchoring Eu^(3+)single atoms.The DFT was employed to optimize the structures of the C:N/Eu^(3+)and NaGdF4:Tb^(3+)/Eu^(3+),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.