Abstract
Two alkaline-borate glass systems of composition x Li2O · 0.2 Cr2O3 · (99.8–x) B2O3 (x = 20, 30 and 40 mol%) and y K2O · (20-y) Li2O · 0.2 Cr2O3 · 79.8 B2O3 (y = 5, 10, 15 and 20 mol%) were prepared by traditional melt-quenching technique. The tunability of their optical spectra, offered by different alkaline contents, allowed disentangling the absorption edge from the characteristic Cr6+ optical transitions. Specifically, the optical band gap is barely affected (3.55 ± 0.15 eV), whilst Cr6+/Cr3+ optical transitions undergo subtle intensity variation with the alkaline content. With increasing the alkaline content, or type, the crystal field strength (10 Dq) is increased, Racah parameters are decreased, and the ligand environment facilitates the crossover from weak into strong ligand field regimes. Electron spin resonance spectroscopy confirmed the existence and quantified the percentage of both Cr6+ (through charge transfer into Cr5+ O−) and Cr3+ oxidation states. Finally, the number of non-bridging oxygen, obtained from Infrared spectroscopy, is increased noticeably for both type and percentage of alkaline, while BO4 structural units increase with Li content and are barely affected for K-doped system.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
