Non-equivalent Pr³⁺centres in Gd₃Ga₁₅O₁₂

Abstract

The P?+ spectra of Gd3GasOn Cwchralski-grown crystals, investigated by absorption, sibselective excitation and emission and fluorescence decays, shows a complex s v U a . Besides the speeba assigned to P?+ in dodecahedral c sites (Dz local symmetry), dt in other sites is also significant. An attempt to assign the most intense lines to svUctural defects is made. Three of the most intense satellite lines are assigned to a P?t(e) ion p d e d by a nearby non-stoichiomemc defect (Gd3+ in octahedral D sites) whose concentration is estimated to be about 7%. The spectra for perturbed Pr3+ centres show additional lines mnnected with a reduction in local symmeuy. Two other lines have been assigned to d C ( c ) -d + ( c ) pairs.The emission decays are almost exponential with similar lifetimes, except one that presents a very strong quenching. This line has been assigned to smngly coupled P?+(c&dt(c) nearest-neighbour pairs. The influence of pair quenching on the relative quanhlm efficiency of ' Po emission is also estimated. This paper reports the data concerning the P$+ multisite structure in Gd3Ga5OI2 (COG), Czochralski-grown crystals. High-resolution transmission, integral excitation spectra, siteselective excitation and emission spectra and lifetime measurements have been performed

Spectroscopic properties of Pr3+:Gd3Ga5O12 crystal

“…By following the calculation equation of quantum efficiency Á = f / r , we can obtain the quantum efficiencies of 3 P 0 → 3 H 6 transitions to be 29.6%, which can be compared with the quantum efficiencies of 1% Pr:YAG (82.3% [37]) and 1% YAP (70% [43]). The relatively low quantum efficiency of this transition might be due to the static perturbations of the crystal fields led by Gd 3+ in octahedral a sites being a non-stoichiometric defect [21]. As demonstrated in Fig.…”

“…There have been many reports on Pr 3+ -doped GGG crystal, thin film or nanocrystalline [19][20][21][22][23][24][25][26], among which the topics involved crystal field analyses, crossrelaxation and energy transfer upconversion processes discussion, structural, luminescence properties investigation, etc. However, to our best knowledge, the Judd-Ofelt (J-O) theory [27,28] as one widely used and effective spectral analysis tool has not been used on Pr:GGG crystal till now.…”

Effect of oxygen pressure on stoichiometric transfer in laser ablation of Pr3+ doped Gd2O3–Ga2O3 binary system

“…More details about the spectroscopic properties of this crystal can be found in Ref. 38. The fluorescence properties of Pr: GdGaO 3 have not been presented so far, but are expected to be similar to those of the isomorphous Pr: YAP crystal.…”

Inorganic Phosphor Materials for Lighting

“…In this perspective, the nature of the sites occupied by Ln 3? ions has been widely discussed and in the literature many contrasting opinions have been reported. This situation occurs for many classes of host matrices of technological interest and in particular for garnet type host lattices [44][45][46], such as YAG, which are described in more detail in Sect. 4.1.…”