UVB-emitting Gd(3+)-activated M2O2S (where M = La, Y) for phototherapy lamp phosphors.

Abstract

Gd(3+)-activated oxysulphide (M2O2S) may be used to study Photoluminescence (PL) properties with respect to phototherapy. Gd(3+)-activated phosphor materials are widely used for phototherapy lamps. The Gd(3+) ion gives characteristic Narrow-Band (NB) emissions, in particular in the ultraviolet (UV) light region, that are used to treat more than 50 types of skin diseases. In this paper, M2O2S oxysulphide doped with Gd(3+) was synthesized by the solid-state flux fusion method and its down conversion spectral properties were studied as a function of different Gd(3+) concentrations. The sample was characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and PL and the crystal structure was also studied. The lanthanum oxysulphide (La2O2S)-activated Gd(3+) ion showed a sharp emission peak at 314 nm when excited at 275 nm excitation, whereas the yttrium oxysulphide (Y2O2S)-activated Gd(3+) ion showed a sharp emission at 316 nm when excited by 272 nm. The effect of concentration of the Gd(3+) ion on the luminescence properties of M2O2S:Gd(3+) phosphor was also studied. These phosphor materials activated with the Gd(3+) ion may be suitable for phototherapy lamps, which are used to treat many types of skin diseases such as psoriasis, vitiligo, or scleroderma.