Efficient broadband NIR emission of Yb3+-activated double-perovskite tungstate Ba0.5MgLaWO6☆

Abstract

Broad-band near-infrared (NIR) phosphors have garnered increasing attention due to the versatile applications in spectroscopy technology fields, but the choice of efficient NIR phosphors remains a challenge. Here, Yb3+-activated cubic double-perovskite tungstate Ba0.5MgLaWO6 was synthesized using a solid-state reaction method. A broadband NIR emission (800–1150 nm) is observed from the 2F5/2→2F7/2 transition of Yb3+ activators in Ba0.5MgLaWO6 under the excitation by UV and near-UV light. Photoluminescence (PL) spectra, decay and emission lifetimes, concentration-dependent intensities, and low temperature luminescence of Yb3+-activated Ba0.5MgLaWO6 were investigated to study the energy transfer (ET) from isolated WO6 polyhedra to Yb3+ activators. The main luminous mechanism involves cooperative energy transfer (CET), wherein, one high-energy excitation photon absorbed by host WO6 group converts to two NIR photons emitted by Yb3+. The partial substitution of Mo6+ for W6+ in Ba0.5MgLaWO6 further leads to a significant increase of the intensity and lifetime of the NIR luminescence. This work provides a feasible strategy for developing a new Yb3+-doped perovskite tungstate, which demonstrates efficient wavelength down-conversion from UV and near-UV to NIR. This material could find versatile applications as an effective NIR luminescent candidate.