六方相LaOF∶Er,Yb的上转换发光及温度传感特性

氟氧化物兼有氧化物优异的稳定性和氟化物的低声子能量,是上转换发光材料的一种热点基质材料,因而研究六方相LaOF∶Er,Yb的上转换发光性能及其温度特性具有重要意义。本文采用水热法制备了六方相LaOF∶Er,Yb荧光材料,通过X射线衍射(XRD)、扫描电镜(SEM)和荧光光谱对其结构和上转换荧光性能进行表征。实验结果表明,水热法120℃得到六方相LaF3,经800℃和1000℃退火后分别形成四方相LaOF和六方相LaOF。980 nm激发下,六方相LaOF∶Er,Yb中Yb3+与Er3+存在能量传递,通过双光子吸收产生绿光和红光的上转换荧光,并且Yb3+与Er3+的最佳浓度分别为3%和1%。最后研究了六方相LaOF∶Er,Yb在温度传感方面的应用,其在150~400 K温度范围的相对灵敏度和绝对灵敏度分别为0.037 K-1和0.0043 K-1。该材料具有优异的温度传感特性,对荧光温度传感器件的设计和应用具有指导意义。

Upconversion Emission and Temperature Sensing of R-LaOF∶Er,Yb

Recent years,Up-conversion(UC)luminescence exhibits potential application in temperature measurement based on FIR(fluorescence intensity ratio)technique,which has drawn considerable attention.Lanthanum oxyfluoride(LaOF)inherits the advantage of low lattice phonon energy,and exhibits superior thermal and chemical stability,showing efficient UC luminescence.Thus,limited attention has been paid to the temperature sensing characteristics of Er3+/Yb3+co-doped LaOF.In the present work,rhombohedral LaOF∶Er,Yb phosphors are prepared using hydrothermal method.The structure and fluorescence properties are characterized by X-ray diffraction,SEM and fluorescence spectra.Hexagonal LaF3 is prepared using hydrothermal method at 120℃.After annealing at 1000℃,rhombohedral LaOF is obtained.The agglomerated particle crystallizes into one larger particle in the range of several micron following annealing.Excited by 980 nm,the characteristic emission from the Er3+ion is observed,including two green emission bands and one red emission,2H11/2→4I15/2 and 4S3/2→4I15/2 as well as 4F9/2→4I15/2 transitions.Energy transfer between Er3+and Yb3+is confirmed because of two-photon process,resulting in upconversion emissions.Finally,the optical temperature sensing properties of R-LaOF∶Yb,Er are investigated.The results suggest that R-LaOF∶Er,Yb exhibits intense emission and high sensitivity.Its maximum relative sensitivity SR and absolute sensitivity SA are 0.037 K-1and 0.0043 K-1 respectively in the temperature range of 150-400 K,suggesting it is a potential candidate in temperature sensing.