A universal strategy to enhance the absolute sensitivity for temperature detection in bright Er3+/Yb3+ doped double perovskite Gd2ZnTiO6 phosphors

Abstract

The absolute sensitivity as a crucial parameter in temperature detection applications is affected by the fluorescence intensity ratio (FIR) of thermally coupled levels (TCLs), whereas no universal research on the utilization of the FIR effect has been performed to rationally achieve high absolute sensitivity. Herein, a universal strategy on the manipulation of the FIR effect is put forward for the first time. In the Er³⁺-activated Gd₂ZnTiO₆ (GZT) system, the maximum absolute sensitivity of 218.8 × 10⁻⁴ K⁻¹ at 313 K is obtained based on this strategy in the ²H_11/2–⁴S_3/2 group, which is enhanced by a factor of 4.6 relative to its original maximum absolute sensitivity. Provably, the maximum absolute sensitivity of 398.7 × 10⁻⁴ K⁻¹ at 313 K in the ²H_11/2–⁴S_3/2 group is gained in the Er³⁺-activated NaYF₄ material, which is enhanced by a factor of 12.3. Such high absolute sensitivity is unprecedented in fluoride upconversion (UC) materials. Besides, high sensitivity and excellent UC emissions suggest that the Er³⁺-activated GZT material may be a candidate for temperature detection. This work offers a universal strategy to enhance the absolute sensitivity and maintain the relative sensitivity and opens a new perspective for the development of temperature detection.