The effect of temperature on green and red upconversion emissions of LiYF4:20Yb3+, 1Ho3+ and its application for temperature sensing

2021 ◽  
Vol 866 ◽  
pp. 158813
Author(s):  
Weichang Li ◽  
Lili Hu ◽  
Wei Chen ◽  
Shiyu Sun ◽  
Malgorzata Guzik ◽  
...  
2019 ◽  
Vol 43 (13) ◽  
pp. 5011-5019 ◽  
Author(s):  
Qinping Qiang ◽  
Yuhua Wang

In this study, to explore new phosphors for temperature sensing with high detection sensitivity, Yb3+/Ho3+/Mn2+ doped hexagonal NaGdF4 nanoparticles were designed.


2021 ◽  
Vol 45 (8) ◽  
pp. 3876-3885
Author(s):  
Yan Peng ◽  
Zhiyuan Cheng ◽  
Wasim Ullah Khan ◽  
Tong Liu ◽  
Menghan Shen ◽  
...  

Pure phase KLu2F7:Yb3+/Er3+/Mn2+ nanocrystals were obtained for which the temperature sensitivity reached up to 45.11 × 10−3 K−1 employing non-thermally coupled levels.


2015 ◽  
Vol 23 (6) ◽  
pp. 7653 ◽  
Author(s):  
Kezhi Zheng ◽  
Weiye Song ◽  
Guanghui He ◽  
Zhen Yuan ◽  
Weiping Qin

Sensors ◽  
2015 ◽  
Vol 15 (12) ◽  
pp. 30981-30990 ◽  
Author(s):  
Baosheng Cao ◽  
Jinlei Wu ◽  
Xuehan Wang ◽  
Yangyang He ◽  
Zhiqing Feng ◽  
...  

2016 ◽  
Vol 16 (4) ◽  
pp. 3768-3771 ◽  
Author(s):  
Y. Y He ◽  
J. L Wu ◽  
X. H Wang ◽  
Z. Q Feng ◽  
B Dong

The Er3+–Yb3+–Li+ codoped TiO2 phosphors have been prepared by sol–gel method. The green and red upconversion emissions were observed under a 976 nm laser diode excitation, which were ascribed to 2H11/2→4I15/2, 4S3/2(I)/4S3/2(II)→4I15/2, and 4F9/2(I)/4F9/(2II)→4I15/2 transitions of Er3+ Stark sublevels. The fluorescence intensity ratios (FIR), which are corresponding to the transitions of 2H11/2/(4S3/2(I)+4S3/2(II)→4I15/2, 4S3/2(I)/4S3/(2II)→4I15/2, and 4F9/2(I)/4F9/2(II)→4I15/2, have been studied as a function of temperature in the range of 303 ∼ 673 K. The temperature sensitivities have been calculated at the maximum value of 0.0020 K-1, 0.0015 K-1, and 0.0011 K-1 at the temperatures of 427 K, 350 K, and 273 K for the three coupled energy level transitions, respectively. The Er3+–Yb3+–Li+ codoped TiO2 phosphor with different temperature sensitivities by Stark sublevels indicated that it is a promising material for application in optical temperature sensing at a wide range of temperature.


Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.


Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).


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