Broadband emission and energy transfer process between silver species in photoluminescent borophosphate glasses

• Published in: Journal of luminescence Vol. 210; pp. 444 - 451
• Main Authors: Seshadri, M., Radha, M., Mendes, G.A., Bell, M.J.V., Anjos, V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2019
• Subjects: Absorption and emission spectra; Borophosphate glass; Energy transfer process; Silver ions; Borophosphate glass; Energy transfer process; Absorption and emission spectra; Silver ions
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2019.02.057

Borophosphate glasses doped with Ag ions have been successfully prepared by melt-quenching method. Their structure and luminescence properties were analyzed by XRD, ATR-FT-IR, TEM, EDS, optical absorption, and photoluminescence measurements. The unique properties of excitation/emission of silver oxide embedded glass matrix, the inhomogeneous broadband character of B (Ag+-Ag0 pairs) and C (Ag+-Ag+ pairs) centers were identified upon 310 nm and 400 nm excitation wavelengths. Under 310 nm excitation, for heat treated samples, the B-center emission becomes narrower with an unexpected blue shift (∼463 nm), and luminescence quenching. Additionally, at 400 nm excitation (surface plasmon resonance of Ag NPs), for all samples, a broadband emission (C-center) was identified at the 450–700 nm range. The suppression of B center emission followed by an inhomogeneous broad region toward the low energy side is interpreted as due to non-radiative energy transfer process. The nanosecond decay curves were recorded at 470 nm (λexc = 310 nm) and 550 nm (λexc = 400 nm), respectively, and were fitted by double exponential function. The observed increase of τ2 (longer lived decay) in HT samples is due to different size/site distribution of Ag nanoclusters/particles in glass. The evolution of τ2 of B and C with HT is an indicative of the energy transfer from B→C and Ag NP→B→C in the studied glasses.