Dual-mode optical thermometry based on glass-ceramics from blast furnace slag

A series of glass ceramic samples precipitated with Ca₂(Mg_0.5Al_0.5)(Si_1.5Al_0.5O₇): Yb³⁺, Er³⁺ nanoparticles were synthesized by the melt quenching method to effectively recycle blast furnace slag. Their structures, morphologies, and luminescent properties were comprehensively investigated using X-ray diffraction, transmission electron microscopy, and photoluminescence, respectively. The impact of adding Al₂O₃/SiO₂ to the blast furnace slag raw material on the transmittance, hardness, and luminescent properties of the glass-ceramics was analyzed. Upon excitation with a 980 nm laser, all glass-ceramic samples emitted strong Er³⁺ upconversion luminescence at 526, 549, and 650 nm. Moreover, the addition of Yb³⁺ ions significantly enhanced the luminescent intensity. A dual-mode temperature sensor based on fluorescence intensity ratios was realized using a single luminescent center. All results indicate that the glass ceramic samples prepared from blast furnace slag are potentially promising for self-referential optical temperature measurement.