Low-temperature wet chemical synthesis and photoluminescence properties of YVO₄: Bi³⁺, Eu³⁺ nanophosphors

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• 作者：Satoru Takeshita ; Tetsuhiko Isobe ; Seiji Niikura
• 关键词：Nanophosphor ; Photoluminescence ; YVO₄ ; Bi³⁺ ; Eu³⁺ ; Wet chemical synthesis
• 刊名：Journal of Luminescence
• 出版年：2008
• 期刊代码：54_00222313
• 类别：ch
• 出版时间：September 2008
• 卷：128
• 期：9
• 页码：1515-1522
• 文件大小：1120 K

摘要

YVO₄: Bi³⁺, Eu³⁺nanophosphors are prepared by the citrate-assisted low-temperature wet chemical synthesis. When the colloidal solution is aged at 60 °C, the crystalline YVO₄: Bi³⁺, Eu³⁺ nanorods are formed from the amorphous gel precursors, as confirmed by transmission electron microscopy and X-ray diffractometry (XRD). YVO₄: Bi³⁺, Eu³⁺ nanophosphors emit red through energy transfer from Bi³⁺ to Eu³⁺ under near-UV-light excitation. The emission intensity increases with increasing the fraction of the crystalline phase during aging. The excitation peak corresponding to Bi³⁺–V⁵⁺ charge transfer relative to those of O²⁻–V⁵⁺ and O²⁻–Eu³⁺ charge transfers gradually becomes strong until the completion of the crystallization, although the contents of individual Bi³⁺ and Eu³⁺ ions incorporated into YVO₄ keep constant. When the aging is continued after the completion of the crystallization, the content of incorporated Bi³⁺ gradually increases, and hence the emission intensity decreases as a result of the energy migration among Bi³⁺ ions. These results suggest that in addition to the fraction of the crystalline phase and the contents of incorporated Bi³⁺ and Eu³⁺ ions, the local chemical states around Bi³⁺ play significant roles in photoluminescence properties.