Cubic Gd2 − xO3:Bix phosphor powders were prepared with a combustion method and the effect of different annealing temperatures and dopant concentration on the photoluminescence (PL), thermoluminescence (TL), and cathodoluminescence (CL) were investigated. A single-phase cubic crystal structure with the Ia3¯ space group was formed. The average crystallite size increased and decreased, respectively, with an increased annealing temperature and an increased Bi3+ doping concentration. Absorption bands at 250, 275, and 315 nm were observed due to 4f-4f transitions of the Gd3+ ions and at 260, 335, and 375 nm due to the excitation of Bi3+ ions. The emission was obtained from two centers associated with the substitution of the Gd3+ ions with Bi3+ ions at the two different sites in the crystal lattice of Gd2O3 (with a point symmetries C2 and S6). The TL glow curves of the UV-irradiated samples showed a low temperature peak at about 364 K and a high temperature peak at 443 K for all the samples. The surface and CL stability during electron irradiation was monitored. The CL emission of the Gd2O3:Bi was stable after removal of surface contaminants. The phosphor might be usable for solid state lighting and displays due to its broad blue-green emission.

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Bi3+ doped strontium oxide (SrO:Bi) phosphor powders were synthesized by the solgel combustion method using metal nitrates as precursors and citric acid as fuel. The optimum Bi3+ doping concentration was found to be 0.2 mol. %, and the optimum annealing temperature was found to be 1100 °C (2 h). The x-ray diffraction patterns corresponded with the known face-centered-cubic structure of SrO. Williamson–Hall plots showed that the crystallite size was in the range of ∼180 nm. Diffuse reflectance measurements of the pure host material showed that it was strongly reflecting (∼100%) down to a wavelength of about 230 nm, but when doped with Bi, an absorption band at 275 nm was observed that increased with Bi concentration. Scanning electron microscopy revealed a cubic morphology, and the grain size increased with annealing temperature. Photoluminescence measurements indicated that the phosphor exhibited efficient blue emission around 445 nm under UV excitation, which also occurred for electron irradiation, but slightly shifted about 5 nm to a longer wavelength. Auger electron spectroscopy (AES) was employed to analyze the surface chemical composition of the powder after pumping to a vacuum pressure of 2.6 × 10−8 Torr and back-filling the vacuum system with O2 to a pressure of 1.0 × 10−7 Torr. By simultaneous monitoring of the cathodoluminescence (CL) and AES peak-to-peak heights over time for 22 h, the CL degradation of the phosphor was investigated. SrO was found to be stable under electron irradiation. The phosphor may have potential applications in the fields of lighting and displays due to its broad blue emission.