Hydrothermal Derived LaOF:Ln3+ (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) Nanocrystals with Multicolor-Tunable Emission Properties

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• 作者：Mengmeng Shang ; Dongling Geng ; Xiaojiao Kang ; Dongmei Yang ; Yang Zhang ; Jun Lin
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：October 15, 2012
• 年：2012
• 卷：51
• 期：20
• 页码：11106-11116
• 全文大小：640K
• 年卷期：v.51,no.20(October 15, 2012)
• ISSN：1520-510X

文摘

A series of LaOF:Ln³⁺ (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) nanocrystals with good dispersion have been successfully prepared by the hydrothermal method followed a heat-treatment process. Under ultraviolet radiation and low-voltage electron beam excitation, the LaOF:Ln³⁺ nanocrystals show the characteristic f-f emissions of Ln³⁺ (Ln = Eu, Tb, Sm, Dy, Tm, or Ho) and give red, blue-green, orange, yellow, blue, and green emission, respectively. Moreover, there exists simultaneous luminescence of Tb³⁺, Eu³⁺, Sm³⁺, Dy³⁺, Tm³⁺, or Ho³⁺ individually when codoping them in the single-phase LaOF host (for example, LaOF:Tb³⁺, Eu³⁺/Sm³⁺; LaOF:Tm³⁺, Dy³⁺/Ho³⁺; LaOF:Tm³⁺, Ho³⁺, Eu³⁺ systems), which is beneficial to tune the emission colors. Under low-voltage electron beam excitation, a variety of colors can be efficiently adjusted by varying the doping ions and the doping concentration, making these materials have potential applications in field-emission display devices. More importantly, the energy transfer from Tm³⁺ to Ho³⁺ in the LaOF:Tm³⁺, Ho³⁺ samples under UV excitation was first investigated and has been demonstrated to be a resonant type via a quadrupole-quadrupole mechanism. The critical distance (R_Tm鈥揌o) is calculated to be 28.4 脜. In addition, the LaOF:Tb³⁺ and LaOF:Tm³⁺ phosphors exhibit green and blue luminescence with better chromaticity coordinates, color purity, and higher intensity compared with the commercial green phosphor ZnO:Zn and blue phosphor Y₂SiO₅:Ce³⁺ to some extent under low-voltage electron beam excitation.