Abstract: Lu₂O₃:Eu³⁺ nanocrystals with various shapes, such as nanorods, nanosheets, and nanoparticles, were synthesized by a hydrothermal approach only through adjusting the pH values of the precursor solutions. The prepared Lu₂O₃:Eu³⁺ nanocrystals were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) spectroscopy, and fluorescence lifetime (FL). With decreasing the samples sizes from nanorods to nanosheets and finally to nanoparticles, the photoluminescence intensity decreases drastically. It is attributed to the gradual increase of OH^- content, which attaches to the surface of nanocrystals, accelerates the nonradiative relaxation and thus lowers the luminescent efficiency. Moreover, the gradually enhanced 624 nm emission line and the continuously extended long excited tails of the charge transfer bands at the long wavelength side, which all originate from the Eu³⁺ ions at or near the surface, are also observed in Lu₂O₃:Eu³⁺ nanocrystals.

Key words: Lu₂O₃:Eu³⁺nanocrystals, hydrothermal approach, photoluminescence, OH^- content, rare earths

摘要： 采用水热方法, 通过调节前驱体的pH值, 得到不同形貌的立方相Lu₂O₃:Eu³⁺纳米棒、纳米片和纳米颗粒。利用粉末X射线衍射(XRD)、扫描电镜(SEM)、傅里叶变换红外(FTIR)光谱、光致发光(PL)谱和荧光寿命(FL)等技术对所制备的纳米晶进行了系列表征。随着纳米晶尺寸的减少, 样品的荧光强度明显减弱, 这是由于吸附在纳米晶表面的OH^-含量逐渐增加, 加速了非辐射弛豫从而降低了发光效率。此外, 也观测到源于纳米晶表面Eu³⁺离子的逐渐加强的624 nm发射以及在长波侧不断延伸的电荷迁移带长激发尾。

关键词: Lu₂O₃:Eu³⁺纳米晶, 水热方法, 荧光, OH^-含量, 稀土