NaScF_(4)∶Yb^(3+)/Er^(3+)纳米颗粒荧光温敏特性

Temperature Sensing Properties in NaScF_(4)∶Yb^(3+)/Er^(3+) Nanoparticles

利用共沉淀法制备了六角相NaScF_(4)∶20%Yb^(3+)/2%Er^(3+)纳米颗粒,该纳米颗粒的尺寸约为35 nm且具有较好的分散性。在980 nm激发下,该纳米颗粒可以产生较强的上转换红光发射及较弱的上转换绿光发射,红绿比约为6。与此同时,在纳米颗粒中,Er^(3+)热耦合的绿光能级^(2)H_(11/2)与^(4)S_(3/2)具有较好的温度感测特性,利用其荧光强度比可实现较为准确的光学温度测量,最大相对灵敏度约为1.17%·K^(-1)。另外,在近红外区,非热耦合的Yb^(3+):^(2)F_(5/2)→^(2)F_(7/2)跃迁与Er^(3+):^(4)I_(13/2)→^(4)I_(15/2)跃迁的荧光强度比也表现出较好的光学测温性能,其相对灵敏度随着温度升高而逐渐增大,并在333 K时达到最大值0.73%·K^(-1)。以上结果表明,NaScF_(4)∶20%Yb^(3+)/2%Er^(3+)纳米颗粒是一种高效的上转换红光材料,且在可见区及近红外区均具有较好的光学测温表现。

In this paper,NaScF_(4)∶20%Yb^(3+)/2%Er^(3+) nanoparticles(NPs)with a size of about 35 nm are prepared by a solvothermal process.Under the excitation of 980 nm wavelength,the NPs exhibit strong red upconversion(UC)emission and weak green UC emission.The corresponding intensity ratio of red emission to green emission is approximately 6.Meanwhile,the green and near-infrared(NIR)emission of the UCNPs own excellent temperature sensing performances within the studied temperature range,which can be used for optical thermometry based on fluorescence intensity ratio(FIR)technology.The maximums of relative sensitivity S_(R) for thermally coupled ^(2)H_(11/2) level and ^(4)S_(3/2) level of Er^(3+) and non-thermally coupled Yb^(3+)^(2)F_(5/2) level and Er^(3+)^(4)I_(13/2) level are 1.17%·K^(-1) and 0.73%·K^(-1),respectively.The results show that the UCNPs are a kind of high efficient red UC material and show promising temperature sensing performances in visible and NIR region.