Search

This paper presents a comprehensive examination of the thermoluminescence properties of BaMgAl10O17: Ce (BAM: Ce) phosphors, which were synthesized via the combustion method. The study employs five distinct approaches to determine the kinetic parameters for individual traps. To investigate the structural, morphological, and elemental composition of the samples, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were utilized. The photoluminescence spectra revealed a broad emission centered around 420 nm upon 330 nm excitation. By subjecting the phosphors to γ doses ranging from 5 to 5 kGy and conducting TL glow curve analysis, the kinetic characteristics of the BAM: Ce phosphors were determined. The linear dose–response was observed for 5–50 Gy, indicating a high sensitivity value. Additionally, there is a consistent estimation of trap energy across various methods. It is also worth noting that the phosphor exhibits a very low minimum detectable dose, estimated to be in the microgray range, making BAM: Ce a strong candidate for low gamma dosimetry applications. [ABSTRACT FROM AUTHOR]

A novel glass system B2O3–SiO2–Bi2O3–TeO2–BaO–ZnO doped with Eu2O3 (x = 0–4 mol%) is fabricated through melt-quench technique and coded as BiTeEu-x. Density and refractive index measurements done on the glasses resulted in the increase up to 5.4377 gcm−3 and 1.99, respectively, for 4 mol% addition of Eu2O3. Vickers micro-indentation measurements done on synthesized glasses gave increasing microhardness values with Eu3+ doping due to higher bond strength of Eu–O bond compared to Te–O bond. The Phy-X/PSD simulation software utilized for obtaining radiation shielding parameters produced highest range of mass attenuation coefficient (63.878–0.036 cm2/g) and lowest range of half-value layer (0.002–3.551 cm) for the same glass proving its superiority in radiation attenuating capacity. This article addresses the theoretical analysis of photon buildup occurring inside the fabricated glasses in 0.015–15 MeV energy range with respect to different penetration depths. Neutron shielding ability of BiTeEu-4 glass was found to be impressive with fast neutron removal cross section (FNR) value of 0.10362 cm−1. [ABSTRACT FROM AUTHOR]

Trivalent erbium ions doped (48 – x) AlPO4 + 15K2O + 12MgF + 20Na2O + 5NaF + xEr2O3 glass samples have been prepared utilizing the melt-quench process and studied to understand the efficacy of Er3+ ions content on physical, structural and luminescence attributes of host glass. The functional groups of the glass structure such as metaphosphate, orthophosphate and pyrophosphate have been elucidated through Fourier Transform Infrared (FTIR) spectroscopic investigation. The least-square approach was used to calculate the Judd–Ofelt parameter from the oscillator strength of the Er3+ ion transitions. The luminescence emission data captured in the visible and near-infrared (NIR) province using 380 and 980 nm excitation wavelengths. The up-conversion (recorded at the excitation at 980 nm) of 0.5 Er glass exhibited emission at 664, 550 and 488 nm wavelengths. The decay plots of the studied glass specimens were measured at 980 nm excitation. The McCumber (MC) theory has been implemented to calculate the gain coefficient of the 0.5 Er glass and flat gain curve was drawn for S-band, C-band and L-band. The attributes for optical amplification were ascertained, including the quality factor (0.85), branching ratio (1), stimulated emission cross-section (1.3 × 10–20 cm2), gain bandwidth (1.26 × 10–25 cm3) and optical gain (0.394 × 10–23 cm2 s) for 0.5 Er glass. The yellowish green light emission ability of the 0.5 Er glass after 980 nm excitation evident through CIE co-ordinates position (x 0.36, y 0.58) at 1931 CIE chromaticity diagram. The spectroscopic and luminescence results endorse that the alumino–phosphate glass specimens loaded with 0.5 mol% of Er2O3 are beneficial for NIR and green light emission applications. [ABSTRACT FROM AUTHOR]

Cerium-doped Ca2Al2SiO7 phosphors were synthesized via the combustion technique and annealed at 1073 K, 1173 K, and 1373 K. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), photoluminescence (PL), and thermoluminescence (TL) studies were performed to explore the variation of structural, morphological, luminescence, and TL properties with annealing temperature. The XRD plot showed an increase in crystallinity with an increase in annealing temperature. Similarly, the enhancement of PL intensity with an increase in annealing temperature supports the increased crystallinity of the phosphor samples. Detailed analysis of traps and trap parameters was carried out using the principle of TL. Samples were irradiated with different γ-ray doses, and, on heating, luminescence was observed. Thus, TL glow curves were drawn and deconvoluted using computerized glow curve deconvolution (CGCD) and Chen's peak shape method to study the traps and trap parameters. With increasing annealing temperature, an increase in TL intensity was observed. Regardless of annealing temperature, every sample displayed a linear dose–response for doses ranging from 3 Gy to 500 Gy. TL investigations suggested that the produced phosphors are suitable candidates for gamma dosimetry applications. [ABSTRACT FROM AUTHOR]

This paper reports on the structural, optical and luminescence studies of Dy3+–Eu3+ co-doped glass ceramics that are obtained via thermal treatment method. The initial confirmation on glass ceramics with the formation of NaBSiO4 crystalline phase was made through XRD study. The FTIR study showed the vibrations of network formers (B2O3, SiO2) and other functional groups. The quantity of non-bridging oxygens (NBOs) are increased in the glass ceramics with increase in annealing temperature. The absorption spectra (UV–visible-NIR) showed the possible transitions of Dy3+ and Eu3+ ions in the glass ceramics. A red-shift in the absorption band-edge and reduction in the optical band gap values were obtained for glass ceramics owing to their heating temperatures. Photoluminescence studies showed the excitations of Dy3+ and Eu3+ ions under 575 nm and 613 nm emission wavelengths. The obtained NaBSiO4 crystalline phase in the glass ceramics has enhanced the luminescence intensity, and lifetimes of Dy3+ and Eu3+ ions compared to unheated precursor glass when excited under 350 nm and 393 nm. Color chromaticity diagram and correlated color temperature (CCT) values showed a shift in the color of light from warm white of precursor glass to neutral white of glass ceramics. The overall results justify the possibility of considering the Dy3+-Eu3+ co-doped glass ceramics as efficient materials for solid-state lighting applications like W-LEDs. [ABSTRACT FROM AUTHOR]

A series of Dy3+ and Eu3+ co-doped zinc aluminoborosilicate (ZABS) glasses were synthesized by a high-temperature melt-quenching method. Visible and NIR transitions of Dy3+-Eu3+ ions are observed through absorption spectra. A reverse trend in the optical band gap values and Urbach energy are seen with addition of Eu3+ ions. Photoluminescence studies recorded under different excitation wavelengths showed a variation in the emission intensities and prevailed the color tuneability behaviour of dopants. The energy transfer between Dy3+ and Eu3+ ions are studied through emission profiles, energy level diagram, and decay curves. The type of multipolar interaction between Dy3+ and Eu3+ are understood via Inokuti-Hirayama (IH) model and Dexter energy model. The CIE chromaticity coordinates, and correlated color temperature (CCT) values suggest that the prepared glasses can be used for light emitting diode application when excited at near-ultraviolet region. [ABSTRACT FROM AUTHOR]