EPR, optical absorption and luminescence studies of Cr3+-doped antimony phosphate glasses

• Published in: Optical materials Vol. 38; pp. 119 - 125
• Main Authors: De Vicente, F.S., Santos, F.A., Simões, B.S., Dias, S.T., Siu Li, M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01-12-2014; Elsevier
• Subjects: Antimony phosphate glasses; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron paramagnetic resonance and relaxation; EPR; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Glasses, quartz; High strength crystalline field; Luminescence; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Optical absorption; Optical materials; Optics; Physics; Trivalent chromium; High strength crystalline field; Antimony phosphate glasses; EPR; Optical absorption; Luminescence; Trivalent chromium; Absorption spectroscopy; Doped materials; Measuring methods; Chromium additions; Phosphate glass; Optical properties; High field; Ultraviolet visible spectrum; Optical materials; Electronic transition; Electron paramagnetic resonance; Absorption spectra; EPR spectra
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2014.10.012

•Cr3+-doped antimony phosphate glasses were prepared.•EPR, optical absorption, and photoluminescence were studied in these glasses.•EPR revealed resonance signals g=5.11 and g=1.97.•Optical absorption spectra allowed evaluating the Racah parameter Dq/B=2.48.•Dq/B indicates that Cr3+ ions are in strong crystal field in this glass system.•Glasses excited with 415nm showed intense Cr3+ emission from 600 to 850nm.
Antimony phosphate glasses (SbPO) doped with 3 and 6mol% of Cr3+ were studied by Electron Paramagnetic Resonance (EPR), UV–VIS optical absorption and luminescence spectroscopy. The EPR spectra of Cr3+-doped glasses showed two principal resonance signals with effective g values at g=5.11 and g=1.97. UV–VIS optical absorption spectra of SbPO:Cr3+ presented four characteristics bands at 457, 641, 675, and 705nm related to the transitions from 4A2(F) to 4T1(F), 4T2(F), 2T1(G), and 2E(G), respectively, of Cr3+ ions in octahedral symmetry. Optical absorption spectra of SbPO:Cr3+ allowed evaluating the crystalline field Dq, Racah parameters (B and C) and Dq/B. The calculated value of Dq/B=2.48 indicates that Cr3+ ions in SbPO glasses are in strong ligand field sites. The optical band gap for SbPO and SbPO:Cr3+ were evaluated from the UV optical absorption edges. Luminescence measurements of pure and Cr3+-doped glasses excited with 350nm revealed weak emission bands from 400 to 600nm due to the 3P1→1S0 electronic transition from Sb3+ ions. Cr3+-doped glasses excited with 415nm presented Cr3+ characteristic luminescence spectra composed by two broad bands, one band centered at 645nm (2E→4A2) and another intense band from 700 to 850nm (4T2→4A2).