镧系离子掺杂NaLuF4纳米晶的可控合成及上转换发光性质研究

采用水热法制备了镧系离子Gd^3+/Yb^3+/Tm^3+和Dy^3+/Yb^3+/Tm^3+掺杂的NaLuF4纳米晶。对样品进行了X-射线衍射分析(XRD)和上转换光谱分析。XRD结果显示所制备的NaLuF4纳米晶的晶相结构、尺寸可通过简单的Gd^3+、Dy^3+掺杂方法来调控,随着Gd^3+、Dy^3+掺杂浓度的增加NaLuF4纳米晶倾向于形成六角相结构,说明高的Gd^3+、Dy^3+浓度能够促进立方相向六角相的转变,有利于六角相结构的形成,为制备结构精确可控的纳米晶提供了一种简单的方法。在980 nm激光激发下,所制备的Gd^3+/Yb^3+/Tm^3+共掺的NaLuF4纳米晶具有强的476 nm的蓝光发射,并且随着Gd3+浓度的增加上转换发光强度逐渐减弱。

Controllable Synthesis and Upconversion Luminescence of Lanthanide-doped NaLuF4 Nanocrystals

In this paper, NaLuF4 nanocrystals doped with Gd^3+/Yb^3+/Tm^3+ and Dy^3+/Yb^3+/Tm^3+ sepsrstely were synthesized by a facile hydrothermal method. The as-prepared samples were characterized by x-ray diffraction ( XRD) and upconversion spectroscopy. The XRD results revealed that the crystal phase and size of the as-prepared NaLuF4 nanocrystals could be readily modified by doping Gd^3+ and Dy^3+. With increasing the content of Gd^3+ and Dy^3+, the NaLuF4 nanocrystals have highly tendency to form hexagonal phase structure, which reveals that the high content of Gd^3+ and Dy^3+ can promote the phase transformation from cubic to hexagonal phase and favor the formation of the hexagonal phase structure. This provides a simple method to synthesize nanocrastals with precisely controlled structure. Under the excitation of 980 nm laser diode, NaLuF4 nanocrystals co-deped with Gd^3+/Yb^3+/Tm^3+ shows intense blue upconversion fluorescence centered at 476 nm. Moreover, the intensity of upconversion luminescence of NaLuF4 nanocrystals gradually decreased with increasing the content of Gd^3+.