Dual-Phase Glass Ceramics Containing ZnGaO:Cr and NaYF:Yb,Er Nanocrystals for Dual-Mode Optical Thermometry.

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 ZnGaO:Cr and NaYF:Yb,Er 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 Cr into ZnGaO and Er into the NaYF lattice in the dual-phase GC. Benefiting from such a spatial separation strategy, the adverse ET processes between Cr and Er 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 Cr and fluorescence intensity ratio (FIR) of Er, with high relative sensitivities of 0.95% K@450 K and 1.24% K@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.