Broad-scope dual-mode modulation thermometry based on up-conversion phosphor GaNbO4: Yb3+/Er3+

Fluorescence temperature measurement technology has set off another upsurge in non-contact temperature measurement, but still suffers from the large error for single-mode thermometry. Herein, in a broad temperature range of 93-633 K, a dual-mode modulation thermometry based on up-conversion phosphor of GaNbO4:Yb3+/ Er3+ is realized with the maximum relative sensitivity (Sr) of 11.7% K-1 (93 K) and 13.1% K-1 (123 K), respectively. GaNbO4:Yb3+/Er3+ phosphors were synthesized by high temperature solid-state method. The structure, surface morphology and the optical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL). The fluorescence intensity ratio (FIR) readout method based on Er3+ thermal-coupled energy level (TCL) and non-thermal-coupled energy level (NTCL) was used to achieve the dual-mode temperature measurement with high temperature resolution and good repeatability in GaNbO4:5 mol% Yb3+ and 5 mol% Er3+ phosphors. All the results show that GaNbO4:Yb3+/Er3+ phosphors have great application potential in high sensitivity broadband thermometry.