NaYF 4 is an efficient host material for lanthanide-based upconversion luminescence and has attracted immense interest for potential applications in photovoltaics, lasers and bioimaging. However, being a non-van der Waals (non-vdW) material, there have been thus far no reports on exfoliation of bulk NaYF 4 to nanosheets and their upconversion luminescence properties. Here, we demonstrate for the first time the fabrication of lanthanide-containing NaYF 4 2D nanosheets using a soft liquid-phase exfoliation method and report on their optical, electronic and chemical characteristics. The nanosheets exfoliated from NaYF 4 :Yb,Er microcrystals consisting mainly of β -NaYF 4 become enriched in α -NaYF 4 post exfoliation and have a large micron-sized planar area with a preferential (100) surface orientation. X-ray absorption spectroscopy confirms that both Yb and Er doping ions are retained in the exfoliated nanoshee...

中文翻译：

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具有上转换发光的单层至几层非范德华二维掺杂镧系元素的NaYF 4纳米片

NaYF 4是基于镧系元素的上转换发光的有效主体材料，并且在光伏，激光和生物成像中的潜在应用引起了极大的兴趣。然而，作为非范德华（non-vdW）材料，迄今为止，尚无关于将整体NaYF 4剥离到纳米片上及其上转换发光性质的报道。在这里，我们首次展示了使用软液相剥离法制备含镧系元素的NaYF 4 2D纳米片，并报道了它们的光学，电子和化学特性。由NaYF 4：Yb，Er微晶剥落的纳米片，主要由β-NaYF 4组成，剥落后富集在α-NaYF 4中，并具有较大的微米级平面面积，具有优先的（100）表面取向。