Controlled synthesis and luminescence properties of NaLnW₂O₈ nanocrystals

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• 作者：Ying Li ; Wei Zhou ; Cheng Wang ; Kai Pan ; Naiying Fan ; Guofeng Wang ; ^{wanggf75@gmail.com} ; Chunmei Sun ; Peng Mei
• 关键词：NaYW2O8 ; Lanthanide ions ; Nanocrystals ; Optical properties
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 出版时间：15 February 2012
• 年：2012
• 卷：514
• 期：Complete
• 页码：157-162
• 全文大小：1113 K

文摘

Tetragonal phase NaLnW₂O₈ (Ln = Y, Yb, Er, Tm, Eu, Gd, Ho, Ce, and Sm) nanocrystals were successfully prepared via a hydrothermal method. It is found that large ionic radii of lanthanide ions and high reaction temperature are beneficial for the formation of NaLnW₂O₈. The upconversion luminescence properties of NaYW₂O₈:Yb³⁺/Er³⁺ and NaYW₂O₈:Yb³⁺/Tm³⁺ were studied under 980 nm excitation. It is found that the luminescence intensity of ²H_11/2 ?#xA0;⁴I_15/2 is much stronger than that of ⁴S_3/2 ?#xA0;⁴I_15/2 as well as ⁴F_9/2 ?#xA0;⁴I_15/2 in NaYW₂O₈:Yb³⁺/Er³⁺. Interestingly, there is no apparent change in the intensity ratio of ²H_11/2/⁴S_3/2 ?#xA0;⁴I_15/2 to ⁴F_9/2 ?#xA0;⁴I_15/2 on Er³⁺ concentration. By analyzing the Raman spectrum, we suggested that the nonradiative relaxation of ²H_11/2 ?#xA0;⁴S_3/2 is inefficient in NaYW₂O₈:Yb³⁺/Er³⁺, resulting in the strong ²H_11/2 ?#xA0;⁴I_15/2 emission. The CIE coordinates of the green luminescence changed with excitation power. While for NaYW₂O₈:Yb³⁺/Tm³⁺, the CIE coordinates of the blue luminescence (0.14, 0.10) is almost unchanged with excitation power. In addition, the photoluminescence of NaYW₂O₈:Eu³⁺ excited at different wavelengths was studied in detail.