Cathodoluminescence properties of Si[O.sub.2]:[Pr.sup.3+] and ZnOSi[O.sub.2]:[Pr.sup.3+] phosphor nanopowders

• Published in: Journal of materials science 2010-10, Vol.45 (19), p.5228
• Main Authors: Mhlongo, G.H, Ntwaeaborwa, O.M, Dhlamini, M.S, Swart, H.C, Hillie, K.T
• Format: Article
• Language: English
• Subjects: Analysis; Diffraction; Powders; X-rays; Zinc oxide
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-010-4563-8

The successful incorporation of ZnO nanoparticles in [Pr.sup.3+] -doped Si[O.sub.2] using a sol-gel process is reported. Si[O.sub.2]:[Pr.sup.3+] gels, with or without ZnO nanoparticles, were dried at room temperature and annealed at 600 °C. On the basis of the X-ray Diffraction (XRD) results, the Si[O.sub.2] was amorphous regardless of the incorporation of [Pr.sup.3+]and nanocrystalline ZnO or annealing at 600 °C. The particles were mostly spherical and agglomerated as confirmed by Field Emission Scanning Electron Microscopy. Thermogravimetric analysis of dried gels performed in an [N.sub.2] atmosphere indicated that stable phases were formed at ≥ 900 °C. Absorption bands ascribed to ³[H.sub.4]-³P(j = 0,1,2), ¹[I.sub.6] and [suip.1][D.sub.2] in the UV-VIS region were observed from Si[O.sub.2]:[Pr.sup.3+] colloids. The red cathodoluminescent (CL) emission corresponding to the ³[P.sub.0] → ³[H.sub.6] transition of [Pr.sup.3+] was observed at 614 nm from dried and annealed Si[O.sub.2]:[Pr.sup.3+] powder samples. This emission was increased considerably when ZnO nanoparticles were incorporated. The CL intensity was measured at an accelerating voltage of 1-5 keV and a fixed beam current of 8.5 µA. The effects of accelerating voltage on the CL intensity and the CL degradation of Si[O.sub.2]:[Pr.sup.3+] and ZnOSi[O.sub.2]:[Pr.sup.3+] were also investigated using Auger electron spectroscopy coupled with an Ocean Optics S2000 spectrometer.