Irradiative thermoluminescence, and defect center analysis in Ni2+ ionic CaAl2SiO6 glass lattice

In this study, we obtained nickel oxide-doped CaAl2SiO6 glasses and analyzed their structural, optical, thermoluminescent, and photoluminescent properties. In general, NiO-doped glasses are useful as optical materials. However, optical materials such as glasses containing Ni2+ ions require refinement of their properties in terms of their structure, thermal stability, microhardness, electrical conductivity, and luminescence to facilitate the development of advanced thermoluminescent materials. Thus, Ni2+ ionic CaAl2SiO6 glasses were synthesized and tested in this study. We observed the amorphous behavior of samples by X-ray diffraction, scanning electron microscopy, differential thermal analysis, and Fourier transform-infrared (FT-IR) spectroscopy. The order of density, oxygen packing density, polaronic radius, molar volume, and refractive index were evaluated for the glasses. The glass transition temperatures were identified using DTA to assess the order of the thermal stabilities, where the highest was found for the Ni0.6Ca9.4Al30Si60 glass. The modes of molecular vibrations for Ni–O–Ni, Ca–O–Ca, Al–O–Al, and Si–O–Si molecules were identified using FT-IR. The highest transmittance intensities were determined for the Ni0.6Ca9.4Al30Si60 glass. The order of the electrical conductivity and activation energy were obtained for glasses using DC conductivity measurements, where the highest was found for the Ni0.6Ca9.4Al30Si60 glass. Optical absorption spectra were recorded for the glasses to determine the order of the band gap (∼0.78 eV) and nephelauxetic ratio (0.799). The photoluminescence was recorded for the glasses at an excitation wavelength of 400 nm to determine the order of the transition probability (∼1.85 S–1) and luminescence emission cross section (∼0.819 × 10−34 cm2). The highest transmittance intensities were obtained for the Ni0.6Ca9.4Al30Si60 glass. Thermoluminescence was recorded for the glasses under gamma irradiation at a dose of 30 kGy, which yielded the shape symmetry factor (∼0.535%), frequency factor (1.31 S–1), and activation energy (∼0.551 eV). Irradiative thermoluminescent analysis suggested a higher order octahedral tendency, and the divalent oxidation states for nickel ions in the glass with an NiO concentration of 0.6 mol% obtained the best thermoluminescent intensities. The orders of the elastic modulus, nephelauxetic ratio, and microhardness for the glasses suggested covalently connected elastic lattices.