Spectral downshifting in Cr3+-Yb3+-Nd3+ doped Ba-Al metaphosphate glass: Role of Nd3+ as bridging ion

Here, Cr3+ sensitized intense luminescence is obtained from Yb3+ ions in a series of newly formulated Cr-Yb doped Ba-Al metaphosphate glass. It has been observed from measured FTIR and absorption spectra that, Yb3+ ion plays the role of network modifier by polymerizing the network in this host. The Yb3+ emission intensity enhanced significantly under Cr3+ excitation in codoped sample due to Cr3+ to Yb3+ energy transfer which is further increased as a function of Yb3+ concentration up to 1 mol% beyond which decrease of luminescence is observed. The energy transfer from Cr3+ to Yb3+ is further improved on inclusion of Nd3+ ions resulting in slight increase of Yb(3+)emission intensity. This indicates the role of Nd3+ ions in bridging the energy gap between Cr3+ and Yb3+ is nominal due to significant red shift of Cr3+ emission in this host to bring about effective spectral downshifting which may prove to be useful for production of flash-lamp pumped Yb3+ lasers as well as solar concentrator applications. (C) 2017 Elsevier B.V. All rights reserved.