Search

This research delves into the influence of red lead content on the red and NIR emission characteristics of Pr3+ ions within a nonconventional antimony silicate glass system. The glasses were synthesized across a composition spectrum of (40 − x) Pb3O4‒49Sb2O3‒(10 + x)SiO2:1Pr2O3, where x ranged from 0 to 35 mol%. Characterization was carried out using XRD, DSC, XPS, and IR spectroscopy. These analyses unveiled the presence of antimony ions in both Sb3+ and Sb5+ states and lead ions in Pb4+ and Pb2+ states within these glass compositions. Optical absorption and emission spectra (at λexc = 445 nm) were recorded within the wavelength range of 400‒1800 nm. Luminescence decay profiles of two pivotal transitions, namely, 3P0 → 3F2 (red emission) and 1G4 → 3H5 (1.3 µm NIR emission), were also recorded. Various radiative parameters from these spectra were extracted using the J–O theory. The findings indicated that, as the Pb3O4 content declined from 40 to 10 mol%, the covalent nature of the samples diminished, resulting in a remarkable amplification in the intensity of both the red and NIR emission bands of Pr3+ ions. The glass containing 10 mol% of Pb3O4 exhibited the most elevated radiative parameters and quantum efficiency. This augmentation was attributed to the reduction of Pb4+ and Sb5+ ions within the glass network or the augmentation of Pb2+ ions, serving as modifiers that mitigated phonon losses. Consequently, glasses with 10 mol% Pb3O4 demonstrate great potential for telecommunications applications, owing to their significant enhancement in PL emission for the 3P0 → 3F2 and 1G4 → 3H5 transitions. [ABSTRACT FROM AUTHOR]

Zinc selenium phosphate glasses added with the traces of Au2O3 were prepared and heat-treated. XRD, TEM, DSC, FT-IR and optical absorption (OA) spectroscopy methods were used for the structural assessment of these samples. Later, different dielectric parameters viz., dielectric constant (ε′), electric moduli (M), impedance (Z) and a.c. conductivity (σac) were measured over wide regions of frequency (ω) and temperature (T) as functions of Au2O3 concentration. Dielectric breakdown strength (DBS) of these samples was also measured at ambient conditions. The characterization studies indicated that multiple crystal grains were entrenched in the residual amorphous phase of the samples. The X-ray diffraction studies revealed that the bulk glasses consisted of Au2(SeO3)3 crystal phase and Au0 metallic particles (MPs). As Au2O3 content was raised, the intensity of the XRD peak related to Au3+ crystal phase indicated a growing trend, whereas that of Au0 MPs showed a decreasing trend. The results of XPS studies revealed similar inferences. The FT-IR results pointed out an improved degree of augmentation of the glass network as the content of Au2O3 was increased. Optical absorption (OA) - spectra of the glasses indicated a broad absorption band in the spectral range of 500–600 nm due to the surface plasmon resonance (SPR) of Au0 MPs. The intensity of the band was observed to decrease as Au2O3 content was increased and indicated decreasing proportion of Au0 metallic particles in the samples. The dielectric parameters exhibited a decreasing trend, whereas the dielectric breakdown strength (DBS) and electrical impedance indicated a substantial hike due to the increasing concentration of Au2O3. Overall, the presence of Au2O3 caused a significant improvement in the insulating strength of the ZnO added SeO2-P2O5 glasses and hence such glasses may be considered as insulating layers in the display panel devices. [ABSTRACT FROM AUTHOR]

This study consists of comprehensive investigations on dielectric permittivity (ε′), electric moduli (M′, M″), impedance (Z), and conductivity (σac) spectra over broad regions of frequency and temperature of lead zirconium silicate glass ceramics mixed with different concentrations of Fe2O3. The observed increase in dielectric permittivity with the content of Fe2O3 is attributed to the increasing presence of iron ions in octahedral positions. Electric moduli plots with frequency (ω) and temperature (T) exhibit dipolar effects. These effects are quantitatively analyzed by Cole–Cole plots; the analysis indicates the distribution of relaxation times. Probable dipoles for these effects are identified and discussed. AC conductivity (σac) shows a rising trend with an increase in Fe2O3 beyond 0.2 mol%, and this increase is attributed to the polaron exchange among Fe2+ and Fe3+ ions. The conduction mechanism is well explained using a polaron tunneling model in the middle‐frequency and high‐temperature regions. [ABSTRACT FROM AUTHOR]