Synthesis and intense ultraviolet to visible upconversion luminescence of YF3:Ho3+ nanoparticles

• Ho3+ single-doped YF3 nanoparticles can emit UV light by absorbing visible light.
• Upconversion luminescence occurred via 3-photon or 2-photon/3-photon processes.
• Y3+/Ho3+ ratio and hydrothermal temperature determine luminescence characteristic.

Ho3+ single-doped YF3 nanoparticles were successfully synthesized by a hydrothermal method. Ultraviolet upconversion luminescence around 288 nm was observed clearly in YF3:Ho3+ nanoparticles under excitation at 450 nm. The structure, composition and upconversion emission properties of the as-prepared products were characterized by X-ray crystallography, scanning electron spectrophotometry, energy-dispersive X-ray analysis, and fluorescence spectrophotometry. Hydrothermal temperature had a significant influence on the size and morphology of YF3:Ho3+ nanoparticles, but the molar ratio of Y3+/Ho3+ had little effect on these characteristics. Upconversion emission spectra demonstrated that the upconversion luminescence properties of the synthesized products were closely related to hydrothermal temperature and the molar ratio of Y3+/Ho3+. The YF3:Ho3+@TiO2 photocatalyst was prepared via a sol-gel process and gave higher photocatalytic activity in degraded Rhodamine B (RhB) than did P25 under Xe lamp irradiation.

Under excitation at 450 nm, ultraviolet upconversion luminescence around 288 nm was observed clearly in YF3:Ho3+ nanoparticles. The intensity of UV emission around 288 nm first increased, and then decreased, as the molar ratio of Y3+/Ho3+ was decreased. The intensity of UV emission around 288 nm decreased as the hydrothermal temperature was increased. The upconversion luminescence mechanism was a three-photon process or a combination of three-photon and two-photon processes.Figure optionsDownload as PowerPoint slide