Influence of titanium redox states on luminescence and conductivity in TiO2 -doped borophosphate glass system

•TiO2-doped barium borophosphate glasses were melt-quenched for optical and electrical studies.•UV absorption analysis showed peak absorption in BPTi4, aligning with the highest Ti3+ ion concentration, as confirmed by XPS.•BPTi4 exhibits strong emission in the 400–600 nm range, optimal for blue LED...

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Bibliographic Details
Published in:Journal of non-crystalline solids 2025-02, Vol.649, p.123334, Article 123334
Main Authors: I, Rashmi, Ingle, Avinash, Raghuvanshi, Vasundhara, Shashikala, H.D., Nagaraja, H.S.
Format: Article
Language:English
Subjects:
AC conductivity
Borophosphate glass
Luminescence
Polaron hopping
TiO2
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Summary:•TiO2-doped barium borophosphate glasses were melt-quenched for optical and electrical studies.•UV absorption analysis showed peak absorption in BPTi4, aligning with the highest Ti3+ ion concentration, as confirmed by XPS.•BPTi4 exhibits strong emission in the 400–600 nm range, optimal for blue LED applications.•Correlated Barrier Hopping is the primary conduction mechanism, with increased AC conductivity due to enhanced polaron hopping between Ti3+ and Ti4+ ion pairs. 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. [Display omitted]
ISSN:0022-3093
DOI:10.1016/j.jnoncrysol.2024.123334