Hydrothermal synthesis and upconversion luminescence properties of ¦Â-NaGdF₄:Yb³⁺/Tm³⁺ and ¦Â-NaGdF₄:Yb³⁺/Ho³⁺ submicron crystals with regular morphologies

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• 作者：Jing Li^a ; ^c ; Zhendong Hao^a ; Xia Zhang^a ; Yongshi Luo^a ; Jihong Zhao^b ; Shaozhe Lü ; ^a ; Jian Cao^a ; ^c ; Jiahua Zhang^a ; ^{zhangjh@ciomp.ac.cn}
• 关键词：Hexagonal prisms ; EDTA ; ¦Â-NaGdF4 ; Hydrothermal synthesis ; UCL properties ; Yb3+/Tm3+ ; Yb3+/Ho3+
• 刊名：Journal of Colloid and Interface Science
• 出版年：2013
• 出版时间：15 February, 2013
• 年：2013
• 卷：392
• 期：Complete
• 页码：206-212
• 全文大小：1436 K

文摘

Single phase ¦Â-NaGdF₄:Yb³⁺/Tm³⁺ and ¦Â-NaGdF₄:Yb³⁺/Ho³⁺ submicron crystals with various morphologies including hexagonal prisms, spindles, and spheres were synthesized via the one-step hydrothermal method by controlling the pH values and sort of chelators (EDTA and citric acid). The prepared products showed intense up-converted luminescence (UCL) pumped by infrared laser at 980 nm. The hexagonal prisms that meaning high degree crystallinity demonstrated strong UCL in comparison with other morphologies such as spindles and spheres. In ¦Â-NaGdF₄:Yb³⁺/Tm³⁺, UCL not only appeared transitions from ¹G₄, ¹D₂, and ¹I₆ states to the lower lying states of Tm³⁺, but also ⁶P_J ¡ú ⁸S_7/2 transition (310 nm) of Gd³⁺. These UCL were responsible for three, five, and six photons processes determined by pump power dependence of UCL intensities. The observation of UCL of Gd³⁺ implied occurrence of energy transfer from Tm³⁺:¹I₆ to Gd³⁺:⁶P_J.