钠铝氟化物包覆BaF2材料上转换发光性能

采用水热法合成了一种非稀土上转换发光材料,由钠铝氟化物和BaF2组成。采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)和扫描电镜(SEM)对其进行了表征,分析表明,钠铝氟化物主要以NaF和Na3AlF6两种晶态存在于BaF2晶体表面,形成化学复合,呈现包覆结构。荧光光谱测试表明,样品在583nm可见光和863nm近红外光室温激发下,均能产生304和324nm的宽波段紫外光发射。时间分辨光谱表明,发光均有一个上升和衰减过程,衰减大约自15ms开始,磷光寿命大于18.4ms。借助上转换发光能量转换过程对发光机理进行了研究,分析表明,发光源于量子限制效应的带间光吸收和界面缺陷的光吸收,发光机制属于量子限制效应-界面发光中心复合发光。

Upconversion properties of sodium and aluminum fluorides coated BaF2 material

Sodium and aluminum fluorides coated BaF2 was synthesized by hydrothermal method. It was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and fluorescence spectrophotometer, respectively. The analysis results indicated that sodium and aluminum fluorides existed in the form of sodium fluoride and sodium fluoroaluminate, which combined with BaF2 surface via chemical bonds, and exhibited coated structure. Fluorescence spectroscopy testing showed that there were two wide upconversion emission peaks with maxima at 304 and 324 nm under the excitation at 583 and 863 nm, respectively. Its phosphorescence life time was greater than 18.4 ms, and the emission intensity exhibited a rising process from the beginning and a decaying process after 15 ms. The luminescence mechanism was proposed according to the energy conversion process of the upconversion emission, the results showed that the upconversion emission belonged to the quantum confinement effect-interface light emission center radiative recombination.