Down- and up-converting dual-mode YPO 4 :Yb 3+ ,Tb 3+ nanocrystals: synthesis and spectroscopic properties

• Published in: Dalton transactions : an international journal of inorganic chemistry 2014, Vol.43 (46), p.17255-17264
• Main Authors: Grzyb, Tomasz, Wiglusz, Rafal J., Gruszeczka, Aleksandra, Lis, Stefan
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/C4DT02234C

Tetragonal YPO 4 nanocrystals doped with Yb 3+ and Tb 3+ ions were synthesized by 900 °C annealing of precursors obtained with a co-precipitation method in the presence of glycerine. These materials exhibited intense green luminescence under ultraviolet excitation and up-conversion emission from the 5 D 3 and 5 D 4 Tb 3+ excited states after irradiation with near infrared light ( λ = 980 nm). The structure and morphology of the products were analysed by recording X-ray diffraction patterns and transmission electron microscopy images. The obtained nanomaterials were single-phased with spherical shaped nanocrystals that had an average size of 18 ± 3 nm. The spectroscopic properties of YPO 4 :Yb 3+ ,Tb 3+ nanocrystals were investigated based on their excitation and emission spectra. The time-resolved luminescence traces were measured, and the luminescence lifetimes of Tb 3+ and Yb 3+ ions were calculated. The most effective dopant concentrations were determined to be 5% Yb 3+ and 15% Tb 3+ , which exhibited the most intense ultraviolet excited emission and up-conversion. Because the integral intensity was observed to be dependent on the power of the pumping laser, a cooperative energy transfer (CET) mechanism underlying the observed up-conversion was proposed.