Preparation and luminescence properties of Y2O3:Er3+/TiO2 with high specific surface area

Abstract

/TiO 2 were prepared using coprecipitation and sol-gel techniques. Their morphology, specific surface area, porosity, UV-vis. absorption spectra and fluorescence spectra were measured using SEM, TEM, surface analysis, UV-vis. absorption and photoluminescence spectrophotometry. SEM and TEM showed that samples prepared using coprecipitation were dispersed, while Y 2 O 3 is a good host material for luminescent agents because of its high chemical and photochemical stability, high melting point, potential for rare-earth doping and low phonon energy (430-500 cm 1 ) [1,2]. Er 3+ strongly absorbs throughout the infrared (IR)-ultraviolet (UV) range and thus is suitable for upconversion studies. Upconversion luminescence in Er 3+ -doped host materials has been extensively studied due to their potential application in optical recording, solid-state lasers, solar cells, and biolabeling [3][4][5][6][7]. In the current study, Y 2 O 3 :Er 3+ was selected because of its favorable physicochemical and luminescence properties.TiO 2 is often considered the most appropriate candidate for photocatalytic processes because of its relatively high photocatalytic reactivity, physical and chemical stability, low toxicity and cost effectiveness [8,9]. TiO 2 applications include sewage treatment, air purification and the photocatalytic reduction of CO 2 . However the photocatalytic activity of TiO 2 is limited by its large band gap (3.0 and 3.2 eV for rutile and anatase phases, respectively). This causes TiO 2 to poorly absorb visible wavelength photons, and UV light (λ<387 nm, about 5% of the visible spectrum) is required to achieve photocatalysis by TiO 2 .

Visible‐light photocatalytic degradation of methyl orange over spherical activated carbon‐supported and Er3+:YAlO3‐doped TiO2 in a fluidized bed

“…Therefore, it was of great interest to extend the light‐responsive region of the photocatalyst to make it use the solar light more efficiently . In this instance, doping of TiO 2 with upconversion luminescence agents that can form a core–shell structure has proved to be a viable approach . Upconversion luminescence agents such as Er 3+ :YAlO 3 can convert visible‐light to UV and make the composite TiO 2 photocatalyst responsive to visible light irradiation …”