Wydział Chemii

Weichang Li

Lili Hu

Wei Chen

Shiyu Sun

Małgorzata Guzik

Georges Boulon

2021

Journal of Alloys and Compounds

866

158813/1-158813/10

10.1016/j.jallcom.2021.158813

Naukowa

Angielski

Artykuł

Optical thermometry is a non-contact temperature detective technique that has high sensitivity and rapid response. In present work, we developed LiYF₄:20Yb³⁺, 1Ho³⁺ (mol%) micro octahedrons obtained by a modified hydrothermal method. The temperature dependent up-conversion (UC) emission and luminescence decays for LiYF₄:20Yb³⁺, 1Ho³⁺ under 976 nm LD excitation with various power density were studied systematically in the temperature range from 100 K to 500 K. The green and red UC emissions are sensitive to the sample temperature whereas the excitation power density in the studied temperature ranges plays a negligible role on the red to green UC emissions ratio. The non-contact optical temperature sensing behaviors were investigated based on the fluorescence intensity ratio (FIR) of red (R3 + R4) and green (G3) at temperature from 100 K to 500 K, which are ascribed to non-thermally coupled levels of Ho³⁺:⁵F₅ and ⁵F₄, respectively. The maximum absolute sensitivity (S_a) of 0.0477 K⁻¹ and maximum relative sensitivity (S_r) of 0.0129 K⁻¹ at the temperature range of 100–500 K based on FIR of (R3 + R4)/G3 were found. The mechanism of temperature effect on UC emission was discussed. The heating and cooling cycle test indicates the high thermal stability of LiYF₄:20Yb³⁺, 1Ho³⁺. These results imply the LiYF₄:20Yb, 1Ho has potential application in ratiometric thermometers and temperature sensing devices.

LiYF4:Yb3+ , Ho3+ micro-crystal, temperature sensing, Fluorescence intensity ratio

http://dx.doi.org/10.1016/j.jallcom.2021.158813

http://www.elsevier.com