Synthesis of Green-Emitting Gd2O2S:Pr3+ Phosphor Nanoparticles and Fabrication of Translucent Gd2O2S:Pr3+ Scintillation Ceramics

Abstract

A translucent Gd2O2S:Pr ceramic scintillator with an in-line transmittance of ~31% at 512 nm was successfully fabricated by argon-controlled sintering. The starting precipitation precursor was obtained by a chemical precipitation route at 80 °C using ammonia solution as the precipitate, followed by reduction at 1000 °C under flowing hydrogen to produce a sphere-like Gd2O2S:Pr powder with an average particle size of ~95 nm. The Gd2O2S:Pr phosphor particle exhibits the characteristic green emission from 3P0,1→3H4 transitions of Pr3+ at 512 nm upon UV excitation into a broad excitation band at 285–335 nm arising from 4f2→4f5d transition of Pr3+. Increasing Pr3+ concentrations induce two redshifts for the two band centers of 4f2→4f5d transition and lattice absorption on photoluminescence excitation spectra. The optimum concentration of Pr3+ is 0.5 at.%, and the luminescence quenching type is dominated by exchange interaction. The X-ray excited luminescence spectrum of the Gd2O2S:Pr ceramic is similar to the photoluminescence behavior of its particle. The phosphor powder and the ceramic scintillator have similar lifetimes of 2.93–2.99 μs, while the bulk material has rather higher external quantum efficiency (~37.8%) than the powder form (~27.2%).

Down/Upconversion Luminescence Behaviors and Temperature-Sensing Properties of Highly Transparent (Er1–xYbx)2O3 Ceramics

“…Figure shows the fluorescence decay behaviors of the (Er 0.995 Yb 0.005 ) 2 O 3 ceramic for the 540 and 668 nm emissions. The fluorescence lifetime can be obtained by the single exponential fitting of the attenuation curve according to the equation: I = A exp­(− t /τ) + B , where τ is the lifetime, t is the decay time, I is the emission intensity, and A and B are constants. − The fittings yield τ = 19.26 ± 0.05 μs, A = 1.91 × 10 17 ± 1.80 × 10 16 , and B = 1.53 ± 0.91 for the 540 nm green emission and τ = 26.60 ± 0.06 μs, A = 4.26 × 10 13 ± 2.36 × 10 12 , and B = 0.82 ± 0.25 for the 668 nm red emission. Apparently, the red emission has a longer lifetime than the green one, which may be caused by the cross relaxation between adjacent Er 3+ …”

Comparative Investigation on Upconversion Luminescence Properties of Lu2O3:Er/Yb and Lu2O2S:Er/Yb Phosphors

“…The average crystallite size ( D XRD ) can be determined from the full width at half maximum (FWHM) of the XRD pattern using Scherrer's formula: D XRD = 0.98 λ/(β· cos θ) , where β is the FWHM, θ is the angle of the diffraction peak, and λ is the wavelength of the X‐ray. [ 24,25 ] By taking the two samples with x = 0.1 as an example, the calculated crystallite sizes are ≈52 for the oxide and ≈130 nm for the oxysulfide.…”

Phase-sensitive radioluminescence and photoluminescence features in Tm3+-doped yttrium tantalates for cyan and white light generation

“…9,10 Among other systems, a ceramic-based scintillator is considered superior to the single crystals typically exploited for radiation measurements, due to its low cost, short production cycle, and large-size production, as well as high dopant concentration with a homogeneous mixture at the molecular level. 11 In particular, lanthanide ions are a proper choice of dopants for such materials, as they have a high atomic number and suitable electronic energy states to emit photons in the UV, visible, and near-infrared (NIR) regions. Elements with a high atomic number included in a host provide sufficiently high-energy electrons that can be converted to lower energy by an appropriate choice of lanthanide sensitizers and emitters.…”