颜色可调CsLa(WO_(4))_(2):Pr^(3+)荧光粉的光致发光和温度传感特性

Photoluminescence and Temperature Sensing Properties of Color-tunable CsLa(WO4)2∶Pr3+Phosphors

利用高温固相法制备了一系列不同Pr^(3+)掺杂浓度的CsLa(WO_(4))_(2)荧光粉,测试了X射线衍射(XRD)、漫反射光谱、激发光谱、发射光谱与荧光衰减曲线,讨论了光致发光光谱与浓度、温度的联系,并基于荧光强度比(FIR)技术计算得出温度传感相关参数。CsLa(WO_(4))2∶Pr^(3+)主要呈现源自3P_(0)和1D_(2)能级的发射,对应的最佳掺杂浓度分别为0.03和0.01,经证实电偶极‐电偶极相互作用导致了浓度猝灭。3P_(0)与1D_(2)能级的发射随温度变化趋势不同,这主要归因于Pr^(3+)‐W^(6+)的价间电荷迁移(IVCT)、交叉弛豫(CR)和多声子弛豫(MPR)等过程的综合作用。由于上述发射表现出不同的浓度和温度依赖特性,实现了颜色可调谐发光。基于3P_(1)→3H_(5)/3P_(0)→3H4热耦合能级对和1D_(2)→3H_(4)/3P_(0)→3H_(4)非热耦合能级对的FIR,计算得到相对灵敏度分别为586.01/T^(2)K^(-1)和1071.78/T^(2)K^(-1),表明该材料在温度传感领域具有潜在应用价值。

A series of CsLa(WO_(4))_(2) phosphors with different doping concentrations of Pr3+were prepared by the high temperature solid-state method.X-ray diffraction(XRD),diffuse reflectance spectra,excitation spectra,emission spectra and fluorescence decay curves were analyzed.The concentration and temperature-dependent luminescent properties were investigated.The fluorescence temperature sensing parameters were calculated based on the fluorescence intensity ratio(FIR)technique.The optimal doping concentrations of Pr^(3+)for the emissions from 3P_(0) and 1D_(2) levels in CsLa(WO_(4))_(2) were found to be 0.03 and 0.01,respectively,and it was confirmed that concentration quenching was caused by the dipole-dipole interactions.The emission trends of 3P_(0) and 1D_(2) levels were different with temperature,mainly due to the effects of the cross-over process to Pr^(3+)-W^(6+)intervalence charge transfer(IVCT)state,cross relaxation process and multiphonon relaxation process.The different concentration and temperature-dependent characteristics of the emissions from 3P_(0) and 1D_(2) levels enabled tunable color emissions.According to the fluorescence intensity ratio(FIR)of 3P_(1)→3H_(5)/3P_(0)→3H_(4) thermally coupled energy levels and 1D_(2)→3H_(4)/3P_(0)→3H_(4) nonthermally coupled energy levels,the calculated relative sensitivities were 586.01/T2·K^(-1) and 1071.78/T2·K^(-1),respectively,indicating the potential application of this material in temperature sensing.