Structural, optical, and down-conversion properties of 100% pure vermilion-emitting Y₂O₃:Sm³⁺, Gd³⁺ for latent wLED applications

This study focuses on the facile combustion synthesis of highly luminescent Y₂O₃:Sm³⁺, Gd³⁺ nanophosphors, bringing down the thermal budget to a minimum of 500 K. When Sm³⁺ ions are doped in the Y₂O₃ cubic crystal system of bandgap 5.6 eV and studied under a down-conversion excitation of 260 nm, the emission spectra offered an intense vermilion color at 608 nm due to the ⁴G_5/2 → ⁶H_7/2 transition within the Sm³⁺ ions. The Y₂O₃:2wt%Sm³⁺ matrix is co-doped with 3wt%Gd³⁺, highlighting 100% pure vermilion emission 4.21 times higher than doped samples, which is a perfect choice for domestic lightening owing to better eye compatibility. Further, post-annealing is performed to improve the structural parameters and luminescence properties, creating sufficient alterations in the crystal lattice. It is professed that Y₂O₃:Sm³⁺, Gd³⁺ nanophosphors can be effectively used in optoelectronic devices, owing to their enhanced crystallinity and photoluminescence properties resulting from the Gd³⁺ → Sm³⁺ energy transfer efficiency of 75.15%.