Effects of pH Values on the Structure, Composition and Luminescence of CaWO₄:Tb³⁺ Thin Films

Abstract:

It is hardly possible to obtain rare earth doped CaWO₄ thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize Tb³⁺-doped CaWO₄ thin films. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that Tb³⁺-doped CaWO₄ films have a tetragonal phase. The ratio of n(Tb)/[n(Ca)+n(Tb)+n(Na)] decreases with the increase of pH value of TbCl₃ solutions. When the pH value (adjusted by NaOH) is higher than 5, Na element has been detected in CaWO₄:Tb³⁺ thin films. Based on the analysis on the composition and luminescence, it can be concluded that the pH value of TbCl₃ solutions must be no higher than 9.1, otherwise, no Tb³⁺-doped CaWO₄ thin films can be obtained. Under the excitation of 237 nm, sharp emission peaks at 543 and 489 nm have been observed for Tb³⁺-doped CaWO₄:Tb³⁺ thin films.

• Periodical: Key Engineering Materials (Volumes 531-532)
• Pages: 204-207
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.531-532.204
• Online since: December 2012
• Authors: Lian Ping Chen, Yuan Hong Gao
• Keywords: CaWo₄, Doping, pH, Tb³⁺, Thin Film

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