Crystalline Size Effect on the Energy Transfer from Mo−O Groups to Eu3+ Ions in R2MoO6:Eu (R = La, Gd, and Y) Crystals

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• 作者：Huaiyong Li ; Siyuan Zhang ; Shihong Zhou ; Xueqiang Cao ; Yuhua Zheng
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：July 30, 2009
• 年：2009
• 卷：113
• 期：30
• 页码：13115-13120
• 全文大小：336K
• 年卷期：v.113,no.30(July 30, 2009)
• ISSN：1932-7455

文摘

Three series of R₂MoO₆:Eu (R = La, Gd, and Y) phosphor powders were synthesized by using the sol−gel method, and then the powder was annealed at a gradually decreased temperature from 1200 to 700 °C. The structures and spectra of the as-prepared phosphors were characterized by powder X-ray diffraction and photoluminescence measurements, respectively. The profile of the Y₂MoO₆:Eu particles was observed by means of field emission scanning electron microscopy. The excitation of the Mo−O groups yields the emission of Eu³⁺ ions, indicating that an energy transfer process takes place from the Mo−O groups to Eu³⁺ ions. With a decrease in annealing temperature, the intensities of the excitation and emission peaks decrease; at the same time, the position of the Mo−O excitation band shifts to the short wavelength direction. The variation of the Mo−O excitation band is discussed from three aspects: crystalline size, coordination environment of Mo, and structural symmetry of the host crystal.