La_0.90Dy_0.05Nb₂O₇ nanosheet phosphor and its multilayer films with enhanced host excitation-mediated photoluminescence

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• 作者：Li-Mei Fu ; Bi-Zhou Lin ; ^{bzlin@hqu.edu.cn} ; ^{beerlin@hqu.edu.cn} ; Yi-Lin Chan ; Ou Zhang ; Bin Li ; Hu Qu
• 关键词：Dy3+ ; Perovskite ; Ln-photoactivated phosphors ; Layer-by-layer assembly technology ; Nanosheets ; Multilayer films ; Photoluminescence
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：5 June, 2012
• 卷：525
• 期：Complete
• 页码：14-21
• 文件大小：945 K

摘要

La_0.90Dy_0.05Nb₂O₇ nanosheets were achieved by exfoliating a layered compound HLa_0.90Dy_0.05Nb₂O₇. Multilayer films composed of the exfoliated nanosheets were prepared by a layer-by-layer deposition technology, which were subsequently heat-treated at 450 掳C and exposed under ultraviolet light to obtain the polymer-free nanosheet films, respectively. The resulting La_0.90Dy_0.05Nb₂O₇ nanosheet suspension and its films exhibit intense emission by the host excitation and negligibly low emission by the direct Dy³⁺ excitation, whereas the photoluminescence emissions of the bulk precursors are largely dominated by the direct Dy³⁺ excitation rather than the host excitation. The comparison between the excitation spectra and the bandgap absorption spectra indicates that the enhanced host excitation-mediated photoluminescence of La_0.90Dy_0.05Nb₂O₇ nanosheet results from the efficient energy transfer from the O-Dy charge-transfer transition to Dy³⁺ within the nanosheet, and that the intensive emission of the multilayer films is attributed to the energy transfer from both of the O-Dy charge-transfer transition and the O-Nb network to Dy³⁺. Dy³⁺ in the La_0.90Dy_0.05Nb₂O₇ nanosheet and the nanosheet-based films gives two emission peaks at around 480 and 576 nm and the blue emission is prominent in the film form.