Investigation on the determinant of upconversion luminescence efficiency and temperature measurement sensitivity based on AWO₄ (Ba, Sr, Ca, and Mg): Er³⁺/Yb³⁺ microcrystals

Abstract

In this work, a comparative study of the upconversion (UC) luminescence properties of E r 3 + − Y b 3 + -co-doped A W O 4 ( A = B a , Sr, and Ca) scheelite phosphors and E r 3 + − Y b 3 + -co-doped M g W O 4 wolframite phosphors is reported. Under 980 nm excitation, all the samples emit green and red emissions. The E r 3 + − Y b 3 + -doped M g W O 4 phosphor has a higher UC emission intensity. Furthermore, the optical temperature sensing properties in E r 3 + − Y b 3 + -co-doped A W O 4 ( A = B a , Sr, Ca, and Mg) phosphor samples are investigated. The relative sensitivity ( S r ) based on thermally coupled levels (TCLs) increases gradually with an increase in matrix phonon energy. The absolute sensitivity ( S a ) values of the samples are accurately predicted by the chemical bonding parameter ( f c ). The results of the correlation between the UC luminescence properties and the microscopic crystal structure, and the relationship of the temperature sensitivity and the host parameters, provide us with a guiding insight for the selection of a host material with ideal temperature measurement capability.

Computational and experimental investigations on structural, electronic and optical properties of scheelite compounds

“…Detailed information on structural improvements can be found in table 1. The obtained lattice parameters and cell volume are similar to previous research results [6,8,27,29,30]. And we give the lattice parameters and unit volume values of previous simulations and experiments in reference [6] and add them to table 1 for comparison.…”

“…The spatial group of these compounds is I4 1 /a tetragonal structure [1][2][3][4][5]. For some tungstate salts consisting of wolframite (A = Fe, Mg, Ni, Co and Zn), their spatial group is P 2 /c, exhibiting a monoclinic structure [6]. In previous studies, tungstate oxide with a tetragonal structure of scheelite was a very important matrix material.…”

“…The Fourier transform infrared spectra were obtained on a Nicolet iS50 (FTIR, Thermo Fisher Scientific, USA) using the KBr pellet technique. The average grain size is computed using the Scherrer equation (1) [6]:…”

“…In previous studies, tungstate oxide with a tetragonal structure of scheelite was a very important matrix material. Due to its good physical and chemical stability, a large number of researchers have studied its upconversion, lighting, and temperature sensitivity [6][7][8][9][10]. Under high hydrostatic pressure, scheelite with a tetragonal structure undergoes structural phase transition, which has been extensively discussed in reference [11].…”

Luminescence, energy transfer, colour modulation and up-conversion mechanisms of Yb3+, Tm3+ and Ho3+ co-doped Y6MoO12

“…The absolute sensitivity ( S A ) of YMO-based material shows a certain advantage among some oxides. 48–51 In addition, the temperature range of YMO is wider than that of molybdate Gd 2 Mo 3 O 9 52 and the relative sensitivity ( S R ) of YMO is higher than Y 2 WO 6 . 49…”