Size dependence of the upconverted luminescence of NaYF4:Er,Yb microspheres for use in ratiometric thermometry
Size dependence of the upconverted luminescence of NaYF4:Er,Yb microspheres for use in ratiometric thermometry
复制标题
用于比例测温的 NaYF4:Er,Yb 微球上转换发光的尺寸依赖性
DOI：
10.1039/c4cp01966k
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发表时间：
2014-01-01
影响因子：
3.3
通讯作者：
Wolfbeis, Otto S.
中科院分区：
文献类型：
--
作者：
Dong, Bin;Hua, Rui N.;Wolfbeis, Otto S.
通过聚丙烯酸辅助水热法制备的NaYF 4：Er，Yb微球的上转换发光具有尺寸依赖的温度敏感性，其尺寸在0.7 ~ 2 μ m之间。结果表明，在223 ~ 403 K温度范围内，它们的绿色上转换发射（峰值在521和539 nm）的荧光强度比（FIR）与晶体的尺寸密切相关。当球的尺寸从0.7 μ m增加到1.6 μ m时，最大灵敏度从36.8 × 10（4）K（1）降低到24.7 × 10（4）K（1）。这种效应主要归因于较小球体的较大比表面积，其中相对大量的Er（III）离子位于表面处。这导致Er（III）离子的S-4（3/2）-> H-2（11/2）布居过程的效率增加，这是由于随着T增加而增强的电子-声子相互作用。通过近红外光加热球体也被认为会导致这种粒子中增强的电子-声子相互作用。
The size-dependent temperature sensitivity is observed on the upconversion luminescence of NaYF4:Er,Yb microspheres with sizes between 0.7 and 2 mu m that are prepared by a poly(acrylic acid)-assisted hydrothermal process. It is found that the fluorescence intensity ratio (FIR) of their green upconversion emissions (with peaks at 521 and 539 nm) is strongly size-dependent at temperatures between 223 and 403 K. As the size of the spheres increases from 0.7 to 1.6 mu m, the maximum sensitivity decreases from 36.8 x 10 (4) to 24.7 x 10 (4) K (1). This effect is mainly attributed to the larger specific surface area of the smaller spheres where a relatively large number of Er(III) ions are located at the surface. This results in an increase in the efficiency of the S-4(3/2) -> H-2(11/2) population process of the Er(III) ions due to stronger electron-phonon interactions with increasing T. Heating of the spheres by NIR light is also supposed to cause enhanced electron-phonon interactions in such particles.