Narrow-Band UVB-Emitting Gd-Doped SrY 2 O 4 Phosphors

Gadolinium (Gd3+) ion-activated SrY2O4 phosphors with varying concentrations of Gd3+ ions were prepared using sol–gel synthesis. The photoluminescence spectra were recorded to study the luminescence behavior of the as-synthesized phosphors. Upon excitation at 275 nm, the material displayed two bands, one at 309 nm (6P5/2 → 8S7/2) and the other at 315 nm (6P7/2 → 8S7/2), in the narrowband ultraviolet (UV) spectral regions. The strong emission at 315 nm indicated that the phosphors could be used as a narrowband UV light source. Electron paramagnetic resonance spectra showed a foremost Gd3+ center with weak signals. Several resonance signals revealed that Gd3+ ions underwent different Zeeman interactions and exhibited varying crystal field strength. The results suggest the potential utility of Gd3+ doped-SrY2O4 phosphors for phototherapy lamp applications which require UV emission.