Preparation, photoluminescence and temperature sensing properties of Dy3+-Eu3+ doped glass-ceramics pyrochlore-containing Ca2Nb2O7 crystalline phase

With the increasing demand for non-contact temperature sensing, the progress of high- performance optical temperature detecting materials is of great interest. In this research, new transparent glass-ceramics containing Ca₂Nb₂O₇ crystals with pyrochlore structure were fabricated through the melt-crystallization approach. Using differential scanning calorimetry (DSC) analysis, X-ray diffractometry (XRD), scanning electron microscopy (SEM) and light transmittance curves, the optimal thermal treatment condition for the glass-ceramic specimens was confirmed as 660 ℃ for 2 hours. Emission spectra originating from the samples showed that the samples achieved cool white light emission with an associated colour temperature of 4621 K. In order to the samples to achieve tunable photoluminescence from cool to warm white light, Eu³⁺ doping was chosen to make up for the absence of red component of Dy³⁺ monodoping and to obtain warm white light emission. The variable temperature spectra of 0.5 mol% Dy³⁺-0.5 mol% Eu³⁺ co-doped glass-ceramic at temperatures within the range of 298 K to 478 K demonstrate that the strength of the emission peaks at 576 nm and 614 nm remain more than 82% of the room temperature at 478 K. The maximum absolute and relative sensitivities of the 0.5 mol% Dy³⁺-0.5 mol% Eu³⁺ co-doped glass-ceramic samples were calculated stemming from the temperature-dependent FIR values of Dy³⁺ and Eu³⁺.The Dy³⁺-Eu³⁺ co-doped pyrochlore-containing Ca₂Nb₂O₇ crystalline phase glass-ceramics investigated in this experiment are expected to be used within the domains of solid-state lighting and temperature sensing.