Contrasting behaviour of the co-activators in the luminescence spectra of Y2O2S:Tb3+,Er3+ nanometre sized particles under UV and red light excitation

• Published in: Nanoscale 2013-02, Vol.5 (3), p.191-196
• Main Authors: Yan, Xiao, Fern, George R, Withnall, Robert, Silver, Jack
• Format: Article
• Language: English
• Subjects: Color; Erbium - chemistry; Erbium - radiation effects; Luminescent Measurements - methods; Materials Testing; Nanostructures - chemistry; Nanostructures - radiation effects; Nanostructures - ultrastructure; Particle Size; Sulfides - chemistry; Sulfides - radiation effects; Terbium - chemistry; Terbium - radiation effects; Ultraviolet Rays; Yttrium - chemistry; Yttrium - radiation effects
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c2nr33391k

Nanometre sized particles of terbium and erbium co-doped yttrium oxysulfide up-converting phosphors were prepared by a urea homogeneous-precipitation method. Results from X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and photoluminescence spectroscopy studies on the microstructure and luminescent properties of the materials are reported. Upconversion emission was observed from the Er 3+ cations when particles were excited with laser light of 632.8 nm wavelength. Under these conditions no interactions between the Er 3+ cations and the Tb 3+ cations were observed. In contrast there was evidence from the Stokes emission of the Er 3+ cations under 254 nm excitation for an interaction between the Er 3+ and Tb 3+ cations reducing intensity of the latter's blue and green emission bands by cross relaxation processes. Upconversion luminescence (black line) is observed from the Er 3+ ions of Y 2 O 2 S:Tb 3+ ,Er 3+ nanoparticles under red laser excitation, whereas downconversion luminescence (red line) is observed from both Tb 3+ and Er 3+ ions under 254 nm excitation.