Tunable broadband upconversion luminescence from Yb3+/Mn2+ co-doped dual-phase glass ceramics

Abstract

In comparison to narrow-band upconversion (UC) luminescence from lanthanide-doped systems, broadband UC emission enables a broad and tailorable emissive color, which is desirable for tunable lasers and multicolor display applications. Herein, dual continuous broadband UC emission covering the visible spectral region at 480–720 nm has been achieved for the first time in Yb3+/Mn2+ co-doped glass ceramics (GCs) functionalized with the precipitation of dual-phase γ-Ga2O3/β-YF3 nanocrystals. A tunable UC emissive color from yellowish to orange could be obtained under 980 nm excitation by varying the Mn2+ doping content and heat treatment temperature of GCs. We ascribe this phenomenon to the typical transition of exchange-coupled Yb3+-Mn2+ dimers in tetrahedral and octahedral ligand environments. The Stokes and power-dependent UC luminescence properties, fluorescence lifetimes, site occupation and the involved UC mechanism are discussed in detail. This research contributes to a better understanding of the UC process between Yb3+ and Mn2+ in transparent hosts and provides a novel perspective for designing broadband-emitting UC materials.