Influence of Yb³⁺ concentration on upconversion luminescence of Ho³⁺

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• 作者：Ying Yu ; Yangdong Zheng ; Feng Qin ; Lixin Liu ; Changbin Zheng ; Guanying Chen ; Zhiguo Zhang ; Wenwu Cao
• 关键词：Upconversion ; Ultraviolet ; Energy transfer
• 刊名：Optics Communications
• 出版年：2011
• 出版时间：15 February 2011
• 年：2011
• 卷：284
• 期：4
• 页码：1053-1056
• 全文大小：356 K

文摘

Upconversion (UC) emissions at 360 ((⁵F, ³F, ⁵G)₂ → ⁵I₈), 392 (³K₇/⁵G₄ → ⁵I₈), 428 (⁵G₅ → ⁵I₈), 554 (⁵S₂/⁵F₄ → ⁵I₈), 667 (⁵F₅ → ⁵I₈) and 754 (⁵S₂/⁵F₄ → ⁵I₇) nm were obtained in 0.1 mol % Ho³⁺/x mol % Yb³⁺:Y₂O₃ (x = 2, 5, 8, 11, 15) bulk ceramics under infrared (IR) excitation at 976 nm. The intensity of the UC luminescence centered at 554 and 754 nm increased with Yb³⁺ concentration from 2 to 5 mol % and decreased from 5 to 15 mol % , while the UC luminescence centered at 392, 428 and 667 nm increased with Yb³⁺ concentration from 2 to 11 mol % , then started to reduce with Yb³⁺ concentration until 15 mol % . This comes from the competition between the energy back transfer (EBT) process [⁵S₂/⁵F₄(Ho) + ²F_7/2(Yb) → ⁵I₆(Ho) + ²F_5/2(Yb) as well as ⁵F₅(Ho) + ²F_7/2(Yb) → ⁵I₇(Ho) + ²F_5/2(Yb)] and spontaneous radiation process. The intensity of the UC luminescence centered at 360 nm always increases with Yb³⁺ concentration from 2 to 15 mol % . We believe that it may come from the cooperation of energy transfer process from Yb³⁺ ions in the ²F_5/2 state and the cross energy transfer process ⁵S₂/⁵F₄ + ⁵I₆ → (⁵F, ³F, ⁵G)₂ + ⁵I₈.