Frequency upconversion based thermally stable molybdate phosphors in a temperature sensing probe

Abstract

Er3+-Yb3+ co-doped NaGd(MoO4)2 phosphors with different concentrations of Er3+ and Yb3+ ions have been successfully synthesized via a high-temperature solid-state reaction method. Phase confirmation and morphological studies have been done...

Superparamagnetic and Light-Emitting Bifunctional Nanocomposites of Iron Oxide and Erbium or Thulium Doped Yttrium Orthovanadate

“…1 and using Checkcell software (see Table 1). Lattice parameters and cell volume determined for the Y 0.9 Ln 0.1 VO 4 samples are slightly lower than those of the YVO 4 oxide, in good agreement with the Shannon ionic radii values of erbium and terbium ions located in bisphenoids: Y 3+ (1.019 Å), Er 3+ (1.004 Å) and Tm 3+ (0.994 Å) [34]. The effect of lanthanide contraction explains a lower value of the cell parameters in the thulium sample [35].…”

“…The first one at 456 cm −1 can be assigned to the antisymmetric stretching vibration of the Y/Er 3+ -O and Y/Tm 3+ -O bonds, while the second broader and more intense band at 775 cm −1 is attributed to the antisymmetric stretching vibration of the V-O bonds in the VO 4 3groups [7,9,20,30,36]. A new strong band appears in the FTIR spectra of Y 0.9 Ln 0.1 VO 4 @SiO 2 at 1077 cm −1 with a small shoulder around 1202 cm −1 assignable to asymmetric stretching vibration modes of Si-O-Si and O-Si-O bonds, respectively [13,19,41]. The band detected at 446 cm −1 can be related to that observed in the uncoated sample spectrum at 456 cm −1 , although it now appears broadened due to the overlap with the bending vibration of the Si-O bonds [13,41].…”

“…13b). The presence of bands in the green region of the spectrum (at 532 and 564 nm) is the result of the 2 H 11/2 4 I 15/2 and 4S 3/2 4 I 15/2 electronic transitions [34,41]. Silica coatings are intended to minimize nanoparticle surface defects and thus lead to an increase in emission intensity in the PL spectra.…”

“…Among them, we are studying yttrium orthovanadate (YVO 4 ) doped with lanthanide ions. This host matrix has good mechanical and thermal properties [1,4,18] and, despite its high phonon energy (700-900 cm −1 ), light emission from lanthanide ions (Ln 3+ ) is very efficient [4,19,20]. The VO 4 3groups display strong UV light absorption, but they do not show light emission because the absorbed energy is dissipated non-radiatively through quenching sites [4,21].…”

Upconverting temperature sensors with high activation energy and low pump threshold

“…Moreover, the thermal resolution (uncertainty; T ) in measurements of sensing parameters, i.e. , the minimal temperature variation that an optical sensor can detect, is estimated from the equation, 53 where δ[ln(FIR)] is the standard deviation of the linear fit to ln (FIR). From eqn (25), it is ensured that higher S r and lesser δFIR are required for better accuracy.…”