Dual-Phase Glass Ceramics Containing ZnGa2O4:Cr3+ and NaYF4:Yb3+,Er3+ Nanocrystals for Dual-Mode Optical Thermometry.

ABSTRACT

Currently, developing luminescent materials for dual-mode optical thermometry has been becoming a rising topic, and concurrent temperature-sensitive optical parameters hold the key. Still, it is a serious challenge, since distinct activators are generally needed and energy transfer (ET) processes among activators inevitably occur, further leading to severe luminescence quenching. Herein, a spatial separation strategy is proposed for designing dual-phase glass ceramics (GCs) containing ZnGa2O4Cr3+ and NaYF4Yb3+,Er3+ nanocrystals (NCs) for dual-mode optical thermometry, in order to integrate diversified activators into one. Structural, morphological, and optical characterizations are examined to verify the partition of Cr3+ into ZnGa2O4 and Er3+ into the NaYF4 lattice in the dual-phase GC. Benefiting from such a spatial separation strategy, the adverse ET processes between Cr3+ and Er3+ could be cut off in the dual-phase GC, contributing to downshifting (DS) and upconversion (UC) luminescence. Furthermore, dual-mode optical thermometry is performed based on the lifetime of Cr3+ and fluorescence intensity ratio (FIR) of Er3+, with high relative sensitivities of 0.95% K-1@450 K and 1.24% K-1@303 K, respectively. It is evidenced that the dual-phase GC holds great potential for dual-mode optical thermometry, and this work also offers a prospective pathway for expanding the practical applications of GC luminescent materials.