On the Gd3+ luminescence and energy migration in Li(Y, Gd)F4−Tb3+

Abstract

The luminescence properties of the Gd3~ion in LiYF 4 and the energy migration among the Gd 3 ions via the 6P 7 2 level and the 617 2 level in the isostructural compound LiGdF4 are reported. The isolated Gd 3~ions in this structure show efficient emission from the 6j level. The non-radiative 6j -* 6P relaxation can be ascribed by a 5-phonon relaxation process, involving 490 cm phonons which are available from the Aṽibrational mode. The decay of the Gd3 ± emission in Li(Y, Gd)F 4 Th 3± can be described by a theory of energy migration developed by Burshtein et a!. Parameters following from these fits indicate that the energy migration among the Gd3 ± ions via the 6 2 level and via the 617 2 level is governed by exchange interaction. Parameters for the Gd3+ Gd3+ and Gd3 + Th3 + transfer rates in this structure are given.

An electron spin resonance and photoluminescence investigation of the effect of annealing temperature on Gd-doped La2Zr2O7 nano-ceramics

“…the time taken for the excited state population to become 1/e of the original value). The decay time value for the system increased from 2.5 ms for the 300 1C annealed sample to 3.5 ms for the 900 1C annealed sample which is in accordance with other literature reports [40]. This also confirmed the decrease in non radiative pathways after annealing the sample at higher temperatures.…”

First Observation of Visible Luminescence from Trivalent Gadolinium

“…The emission wavelengths agree very well with the calculated energy differences between the measured 6G' energy values (Fig. 2) and the 6ΡJ energy levels for LiYF4:Gd 3 + from [4]. As far as we are aware, the 6G,ß -6 Pj emission is the first observed visible luminescence from Gd3 +.…”

“…In Fig. 1 (right side) the energy level scheme for Gd3+ in LiYF4 derived from the present and previous observations is depicted [4]. Upon excitation in the 6GJ levels, 6GJ -6 ΡJ emission lines were observed in the visible, viz.…”

Quantum cutting abilities of sol–gel derived LiGdF4:Eu3+ powders

“…Such a result demonstrates that this soft synthesis way enables to achieve high quality phosphors with a uniform repartition of doping rare-earth ions within the host lattice so that there is no clustering effect which would affect significantly the energy transfer rate from Gd to Eu. This latter was proved to occur via energy migration over the Gd 3+ ions sublattice so that Eu 3+ ions must be in their close neighborhood to be populated on their high energy levels [19]. By integrating the intensities in emission spectra, a formula has been established [8] to assess the efficiency of the cross-relaxation step and, therefore, the quantum cutting efficiency.…”