Blue Light-excitable Ultra-broadband Near-infrared Emission of KMgF3∶Cr3+/Ni2+Nanocrystals Embedded in Glass Ceramics
The growing interest of near-infrared(NIR)spectroscopy in food science,information security,and bio-medicine and other important national economy and people's livelihood fields,has put forward higher demand for NIR light source.It is consequently becoming an important and urgent task to develop near-infrared light sources with highly efficient ultra-broadband emission.In this paper,perovskite KMgF3 nanocrystals were successfully pre-cipitated from a fluosilicate glass matrix SiO2-K2CO3-KF·2H2O-MgF2 via a melt quenching technique.By varying content of SiO2,K2CO3,and MgF2 and heat treatment temperature,the precipitation of KMgF3 nanocrystals can be controlled,and thus glass ceramics with optimized crystallization and transparency were obtained.The crystallized KMgF3 nanocrystals in the glasses provide a stable octahedral coordination and low phonon energy environment for Cr3+and Ni2+.Under 450 nm blue light excitation,dual-broadband NIR emission originating from Cr3+(700-1 200 nm)and Ni2+(1 400-1 700 nm)is achieved based on the energy transfer from Cr3+to Ni2+.The relative intensity of the NIR-emitting bands varies with the concentration of doping ions.Energy transfer behavior from Cr3+to Ni2+is demon-strated according to the measured emission spectra and decay curves,showing a maximum energy transfer efficiency of 52.2%.The energy transfer mechanism can be attributed to electron dipole-quadrupole interaction.The research results not only provide reference data for systematically understanding the regulation of ultra-broadband lumines-cence of transparent optical materials,but also contribute to the exploration of cost-effective and efficient broadband NIR light source.