Luminescence study of Eu3+ doped GdVO4 nanoparticles: Concentration, particle size, and core/shell effects

Abstract

Nanoparticles of GdVO4 doped with Eu3+ and core/shell of GdVO4:Eu3+/GdVO4 are prepared by urea hydrolysis method using ethylene glycol as capping agent as well as reaction medium at 130 °C. Unit cell volume increases when GdVO4 is doped with Eu3+ indicating the substitution of Gd3+ lattice sites by Eu3+. From luminescence study, it is confirmed that there is no particle size effect on emission positions of Eu3+. Optimum luminescence intensity is found to be in 5–10 at. % Eu3+. Above these concentrations, luminescence intensity decreases due to concentration quenching effect. There is an enhancement in luminescence intensity of core/shell nanoparticles. This has been attributed to the reduction in surface inhomogenities of Eu3+ surroundings by bonding to GdVO4 shell. The lifetime for D50 level increases with annealing and core/shell formation.

Surface modified Eu:GdVO4 nanocrystals for optical and MRI imaging

“…5 (top) shows the excitation spectrum recorded for the Eu 0.10 Gd 0.90 VO 4 (10% Eu content) nanophosphors monitored at the most intense Eu 3+ emission band (618 nm). As observed, it consisted of a strong broad band centered at 274 nm, which has been previously observed for several Eu-doped LnVO 4 systems [20][21][22][23] and attributed to the overlapping of two charge transfer (CT) processes involving Eu-O and V-O components, the former appearing at higher energy 21,24 or to electric and dipole-allowed transitions from the 1 A 2 to the 1 E and 1 A 1 excited states of the VO 4 3− ion. 20 Some other bands resulting from f-f transitions of Eu 3+ were also found (inset in Fig.…”

Structural and photoluminescence properties of red-light emitting YVO4:Eu3+ phosphor synthesized by combustion and solid-state reaction techniques: a comparative study

“…-doped YVO 4 nanocrystals prepared by conventional solid-state reaction and combustion method. The intense transmittance band noticed near 830 cm -1 for all the samples is the characteristic infrared (IR) band of VO 4 3-which normally arises in the range of 780-920 cm -1 [24,25]. As-prepared samples show the band at around 450 cm -1 attributed to the Y-O vibrational mode [24].…”

Luminescence Properties of Redispersible Tb3+‐Doped GdPO4 Nanoparticles Prepared by an Ethylene Glycol Route

“…This was carried out by considering the following assumptions: [10,12,[34][35][36][37] (i) the homogeneous distribution of Tb 3+ ions in the host matrix, and (ii) Tb 3+ ions may be located closer to the surface due to a strong ligand-Tb 3+ interaction and a strong quenching effect at higher concentrations. And the second-order exponential decay is given as Equation (2).…”

“…The τ average is calculated using the following equation [Equation (3)]. [10,12,[34][35][36][37] τ average = (…”

“…The possibilities of such biexponential decay are [10,12,[34][35][36][37] (i) a difference in the nonradiative probability of decays for lanthanide ions at or near the surface and in the core of the particles, (ii) an inhomogeneous distribution of the dopant ions in the host material, which leads to the variation in the local concentrations, and (iii) the transfer of excitation energy from donor to lanthanide activators. Of the two exponential fits, we observed a better fit with the biexponential equation than with the monoexponential one (Figure 10), that is, the goodness of fits of parameters for 7 atom-% Tb-doped GdPO 4 with mono-and biexponential equations were found to be 0.9916 and 0.9979, respectively.…”