808 nm-triggered optical thermometry based on up-conversion luminescence of Nd3+/Yb3+/Er3+ doped MIn2O4 (M = Ca, Sr and Ba) phosphors
808 nm-triggered optical thermometry based on up-conversion luminescence of Nd3+/Yb3+/Er3+ doped MIn2O4 (M = Ca, Sr and Ba) phosphors
复制标题
基于 Nd3 /Yb3 /Er3 掺杂 MIn2O4（M = Ca、Sr 和 Ba）荧光粉上转换发光的 808 nm 触发光学测温
DOI：
10.1039/c8dt00913a
复制
发表时间：
2018-05-21
影响因子：
4
通讯作者：
Niu, Mu
中科院分区：
文献类型：
--
作者：
Liu, Xue;Li, Ting;Niu, Mu
808 nm激发下基于上转换（UC）荧光强度比（FIR）的光学测温技术在富水环境中更为理想，而研究宿主依赖灵敏度的模糊内在影响因素是开发高灵敏度测温技术的先决条件。本文采用溶胶-凝胶法制备了具有低声子能量的MIn2O4:Nd3+/Yb3+/Er3+ (M = Ca, Sr, Ba)微晶体。通过控制Yb3+的含量，获得了从绿色到红色可调的强UC发光，并利用寿命测量阐述了Nd3+-> Yb3+-> Er3+的UC机理和连续能量转移。基于Er3+的热耦合能级(S-4（3/2)/H-2(11/2)）评价了样品的热感测性能，随着温度的升高，它们的灵敏度逐渐增加，在490 K时，M = Ca、Sr和Ba的灵敏度分别达到最大值0.0048、0.0033和0.0058 K-1。通过对主体结构、M2+离子的位对称性和M-O键特性的分析，提出CaIn2O4中较高的Ca-O键共价导致其灵敏度优于相同结构的SrIn2O4，而BaIn2O4的最佳灵敏度主要归因于配位较高、化学键较长的Ba2+位点的特定局部晶体场。这些结果为选择合适的基体材料以实现更高的温度检测灵敏度提供了见解。
Optical thermometry based on up-conversion (UC) fluorescent intensity ratio (FIR) with 808 nm excitation is preferable in water-rich environments, and investigation of the ambiguous intrinsic influencing factors on host-dependent sensitivity is a prerequisite for the development of highly sensitive thermometry. Herein, MIn2O4:Nd3+/Yb3+/Er3+ (M = Ca, Sr, and Ba) microcrystals with low phonon energy are synthesized via a sol-gel method. Intense UC luminescence with tunable emission color from green to red is obtained by controlling the Yb3+ content, and the UC mechanisms and successive energy transfer of Nd3+-> Yb3+-> Er3+ are elaborated using lifetime measurements. The thermal sensing properties of the samples based on the thermally coupled levels (S-4(3/2)/H-2(11/2)) of Er3+ are assessed, and their sensitivities increase gradually with an increase in temperature and reach the maximum of about 0.0048, 0.0033 and 0.0058 K-1 at 490 K for M = Ca, Sr, and Ba, respectively. By analysing the host structure, site symmetry of M2+ ions and characteristics of the M-O bonds, it is proposed that the higher Ca-O bond covalency in CaIn2O4 leads to better sensitivity than SrIn2O4 with the same structure, and the optimal sensitivity in BaIn2O4 is mainly attributed to the specific local crystal field of the Ba2+ site with higher ligancy and longer chemical bonds. These results provide insight for the selection of appropriate matrix materials to achieve higher temperature detection sensitivity.