Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
7 results
Search Results
Item Influence of V2O5 addition as a dopant and dispersed content in barium borophosphate glass on structural and optical properties(Elsevier Ltd, 2024) Rashmi, I.; Ingle, A.; Raghuvanshi, V.; Shashikala, H.D.; Nagaraja, H.S.The Barium Borophosphate glass system with molar compositions 40P2O5– 25B2O3-(35-x) BaO-xV2O5 and 40P2O5–25B2O3–35BaO-xV2O5 (x = 0,1,3,5 mol%) was synthesized using melt-quenching method. A comprehensive investigation of the structural and optical properties was conducted to compare the effects of V2O5 as a dopant and as an addition to the glass matrix. The physical parameters were assessed through the measurement of density. The influence of V2O5 introduction on vibrational modes was studied through Fourier-transform infrared (FTIR) and Raman spectroscopy. The UV–visible absorbance analysis unveiled the existence of multiple valence states of vanadium (V3+, V4+ and V5+). The reduction in bandgap was determined through the utilization of a Tauc plot, while the measurement of the refractive index allowed for the assessment of its variation with the composition of V2O5. Photoluminescence spectroscopy (PL) was employed to explore the presence of intrinsic defects within the glass matrix and the impact of V2O5 on the emission spectra. Furthermore, CIE chromaticity coordinates of synthesized samples were observed in both the white and blue regions, suggesting their potential application in display devices. Significantly, V2O5 glass doped with 1 mol% displayed chromaticity, characterized by CIE coordinates x = 0.288 and y = 0.386, closely matching the white region as well as the bandpass filter. The introduction of transition metal oxide dopants into borophosphate glass yielded exceptional emission properties. The ability to modify optical properties makes it more promising for these glass materials, particularly for applications like optical filters and displays. © 2024 Elsevier Ltd and Techna Group S.r.l.Item A comprehensive study uncovering physical, structural, and optical properties of Cu2O and TiO2-reinforced borosilicate glasses as optical filters(Elsevier B.V., 2024) Raghuvanshi, V.; Rashmi, I.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.In this study, the integration of transition metal oxides (TMOs), specifically Cu2O and TiO2, into a borosilicate glass matrix (30SiO2–35B2O3–35Na2O–5CaF2-X (TMO)) was investigated for enhanced glass functionality. Glass samples with varying TMO concentrations (X = 0, 1, 2, 3, 4 mol%) were prepared using the melt-quenching technique. X-ray diffraction confirmed the amorphous nature of the synthesized samples, while FTIR analysis showed structural changes, transitioning from trigonal BO3 to BO4 tetrahedra, alongside the formation of non-bridging oxygen species due to TMO integration. UV–Vis spectroscopy demonstrated a red shift in optical absorption profiles, correlating with a reduction in the indirect band gap as TMO content increased. Photoluminescence studies showed distinct behaviors, with Cu2O suppressing emission peaks and TiO2 exhibiting intriguing blue and green emissions, diminishing at higher concentrations. It was attributed that Cu2O had a larger impact on altering the glass network than TiO2. These findings contribute to understanding the properties of Cu2O and TiO2-containing borosilicate glasses, suggesting tailored optical properties for potential applications as bandpass filter and UV blocker. © 2024 Elsevier B.V.Item Synergistic enhancement of optical properties in erbium-doped borate glasses through copper nanoparticle incorporation(Elsevier Ltd, 2024) Ingle, A.; Shashikala, H.D.; Udayashankar, N.K.The present study investigated the impact of incorporating copper nanoparticles (CuNPs) on the optical properties of erbium-doped borate glasses. Through melt-quenching and heat treatment techniques, glasses with varying Cu2O concentrations (x = 0–5 mol%) were synthesized. Physical and structural analyses revealed that Cu ions serve as effective network modifiers. They foster the formation of a greater proportion of BO4 tetrahedra and thus enhancing glass homogeneity. Optical absorption spectra demonstrate a distinct modulation of Er3+ absorption bands with Cu2O embedding, indicating the formation of CuNPs, as validated by the emergence of surface plasmon resonance bands. This structural evolution results in a noticeable reduction in the bandgap energy, signifying improved semiconducting behavior. Judd-Ofelt analysis highlighted the profound influence of CuNPs on hypersensitive transitions, thereby affecting oscillator strength. Photoluminescence measurements revealed amplified emission in the visible red and near infrared (NIR) region, attributed to the synergistic effects of CuNPs and Er3+ ions, with 5 mol % Cu2O exhibiting the highest emission intensity. Analysis of the radiative properties validates the enhancement of the emission cross-section, gain bandwidth, optical gain and radiative transitions. These enhancements contribute to a notable increase in the branching ratio from 0.91 % to 5.41 % accompanied by an increase in the quantum efficiency from ∼79 % to ∼90 %. Moreover, decay analysis revealed a notable enhancement in lifetime from 3.03 ms to 15.74 ms, which is indicative of enhanced radiative transitions. Overall, the incorporation of CuNPs into erbium-doped borate glasses facilitates significant enhancements in physical, structural, and optical properties. This positions them as promising materials for a wide array of optoelectronic applications. This comprehensive study sheds light on the complex interplay between CuNPs and erbium-barium borate glasses, offering valuable insights for the development of advanced optoelectronic materials with enhanced performance and functionality. © 2024 Elsevier Ltd and Techna Group S.r.l.Item Anomalous Photoluminescence Behavior and Judd–Ofelt Analysis of Erbium-Barium Borate Glass Embedded with Copper Oxide Nanoclusters(Springer, 2024) Ingle, A.; Shashikala, H.D.Glasses doped with rare earth elements have been extensively researched for the purpose of creating novel and effective photonic devices. The impact of the LSPR of metallic nanoparticles on rare earth–doped glass for manipulating luminescent properties is a new matter of study. As a result, the localized surface plasmon resonance (LSPR) of metallic nanoparticles (NPs) in amorphous materials may create new opportunities in the disciplines of optics and photonics. Therefore, erbium-barium borate glasses with a 60B2O3-38.5BaO-1.5Er2O3-xCu2O-xSnO (x = 0, 1, 2, 3, 4, 5 mol%) composition were synthesized by the melt quenching technique. The synthesized glasses were then preliminarily subjected to HR-TEM, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopic analysis for structural investigation. A consistent linear trend was observed for Cu2O concentrations from 1 to 4 mol%, but a remarkable nonlinear anomaly emerged beyond the threshold concentration of 5 mol% Cu2O. This inflection point played a pivotal role, leading to the formation of Cu0, as confirmed by LSPR in UV–visible spectroscopy, significantly impacting the glass properties. Spectroscopic attributes, including branching ratio and stimulated emission cross section, underwent notable changes, particularly at 5 mol%, showcasing enhanced branching from 13.17 to 19.20% and quantum efficiency from 28.91 to 36%, positioning BEC5 as a promising candidate. The incorporation of copper nanoparticles up to the optimized threshold level allowed for the customization of overall glass attributes. Also, a discernible shift observed in chromaticity coordinates from green to yellow region draws attention to tunable display application. The current study intends to improve the understanding of the interactions between the compositional, structural, and optical properties of copper oxideembedded erbium-barium borate glasses for photonic and lasing applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Item A study on the influence of geometric coordination of cobalt ions on the structural, physical and optical properties of borosilicate glass(Elsevier Ltd, 2025) Raghuvanshi, V.; Rashmi, R.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.This work explores the synthesis and characterization of cobalt oxide-added borosilicate glass using the melt-quenching technique. The glass system was investigated using various methods, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), density measurements, UV–vis spectroscopy, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy. XRD validated the glass's amorphous nature, while FTIR results indicated significant bonding alterations, showing a transition from BO3 to BO4 units and from B3-O-Si to B4-O-Si linkages. The increased glass density further supported the formation of BO4 units. XPS analysis verified the presence of Co2+ and Co3+ ions within the glass matrix. Optical absorption studies revealed distinct electronic transitions for Co2+ ions in both tetrahedral and octahedral coordination, and for Co3+ ions in octahedral coordination, which was corroborated by EPR spectroscopy. The paramagnetic nature of Co2+ ions was analyzed, and the g-value was determined using X-band frequency. The study also noted the narrowing of the indirect band gap with the rise in the content of Co3O4, and the examination of the metallization criterion suggested a potential metallic nature for the synthesized glasses. Notably, the 0.05 mol% Co3O4-added sample exhibited a 48 % transmission rate and the highest emission, highlighting its potential as an optical bandpass filter. These findings underscore the versatility and tunability of cobalt oxide-added borosilicate glass for various optical technologies. © 2024 Elsevier Ltd and Techna Group S.r.l.Item Influence of titanium redox states on luminescence and conductivity in TiO2 -doped borophosphate glass system(Elsevier B.V., 2025) Rashmi, R.; Ingle, A.; Raghuvanshi, V.; Shashikala, H.D.; Nagaraja, H.S.Borophosphate glasses have garnered significant interest due to their potential for optical and electronic applications. This research delves into the luminescent and conductive properties of 40P2O5–25B2O3-(35-x) BaO-xTiO2 (x = 0–5 mol%) glasses synthesized via the melt-quench method. The glass doped with 4 mol% TiO2 exhibited intense luminescence within the 400–600 nm spectrum, manifesting as a vivid blue emission and the highest Ti3+ ion concentration. Beyond this threshold, the luminescence intensity waned, highlighting the significance of Ti4+/Ti3+ ratios. Absorption spectra and X-ray photoelectron spectroscopy were utilized to study these multivalent ions. Temperature-dependent AC conductivity, exhibited a linear increase, consistent with the Correlated Barrier Hopping (CBH) model. Enhanced polaron hopping between Ti3+ and Ti4+ with increasing TiO2 content improved the dielectric constant and conductivity, peaking at 4.145×10?5 Scm?1 at 5 mol% TiO2 within the 450–530 °C range. These findings underscore the tunability of TiO2-doped glasses for optoelectronic applications. © 2024 Elsevier B.V.Item Influence of low concentrations of vanadium and titanium ions on the structural and optical properties of borophosphate glasses(Elsevier B.V., 2025) Rashmi, I.; Raghuvanshi, V.; Ingle, A.; Shashikala, H.D.; Nagaraja, H.S.A series of P2O5–B2O3–BaO glass system containing various V2O5 and TiO2 content (from 0.25 to 0.75 mol%) were synthesized using the melt-quenching method to examine their structural, EPR, and optical characteristics. EPR analysis confirmed VO2+ hyperfine splitting and the presence of Ti3+ ions in a tetragonally compressed octahedral structure. The local structures of VO2+ and Ti3+ centers were explored through spin Hamiltonian parameters (g??e) and optical transition energies. UV–visible spectroscopy revealed multiple oxidation states of vanadium (V3+, VO2+ and V5+) and titanium (Ti3+, Ti4+), which significantly influenced the optical characteristics. Photoluminescence (PL) studies indicated the presence of oxygen vacancies and intrinsic defects in the glass matrix, with [VO4]3- groups and Ti3+ ions significantly enhancing emission properties. The enhanced luminescence was observed for glasses with 0.75 mol% TiO2 and 0.75 mol% V2O5. Notably, the 0.75 mol% V2O5-doped glass, exhibited CIE chromaticity coordinates (x = 0.26, y = 0.31), closely aligning with standard white light. The tunability of optical properties through transition metal oxide doping highlights the potential of these glasses for advanced photonic applications, including optical filters and display technologies. © 2025 Elsevier B.V.