Multimodal synergistic thermometry: designing wide-range optical thermometers via Eu3+/Er3+ co-doped YVO4
Abstract
In this paper, a five-mode synergistic thermometry system based on Eu3+/Er3+ co-doped YVO4 fluorescent material was developed. By utilizing the spectral properties of the phosphor, two luminescence intensity ratio (LIR) and two excitation intensity ratio (EIR) thermometry modes were established, and the luminescence lifetime thermometry (τ) mode of Eu3+ 5D0 → 7F2 was also introduced into this system. The Sr values of both Er3+- and Eu3+/Er3+-based LIR modes decrease with increasing temperature, and the maximal value of Sr (Srmax) is 0.98% K−1 at 300 K. Similarly, the EIR mode via V–O charge transfer (monitoring Er3+ emissions) shows a declining Sr trend, and the Srmax of the EIR mode via V–O charge transfer (monitoring Er3+ emissions) is 1.01% K−1 at 300 K. Unlike conventional LIR systems, the EIR mode based on Eu3+ (7F0 → 5D4/7F0 → 5L6) exhibits a distinctly different temperature dependence in its Sr value, and at 500 K the Srmax of Sr of YVO4:Eu3+,Er3+ can reach 0.65% K−1. The Srmax of the τ mode can reach 0.71% K−1 at 500 K, which is superior to that of other systems. Notably, the EIR and τ modes address the limited high-temperature sensitivity of Boltzmann-type thermometry. In short, the YVO4:Eu3+,Er3+ phosphor exhibits excellent thermometric performance and application potential.