Multi-mode optical manometry based on Li${}_4$SrCa(SiO${}_4$)${}_2$:Eu${}^{2+}$ phosphors

Optical manometry is a highly promising method for measuring pressure. However, its wider application is limited by the lower sensitivity and influenced by environmental factors. Herein, multi-mode optical pressure sensors based on Eu${}^{2+}$-doped Li${}_4$SrCa(SiO${}_4$)${}_2$ phosphors suitable for a variety of complex pressure-measuring environments are designed. The phosphors contain two separate luminescence centers at 443 nm (Eu${}_{Sr}$) and 584 nm (Eu${}_{Ca}$), respectively. In the lower pressure range, the emission peak undergoes a massive redshift of 5.19 nm GPa${}^{-1}$ of Eu${}_{Ca}$, which is 14× better than commercially available ruby sensors. In order to improve the pressure response range and the accuracy of pressure measurement, for the first time, a new approach in the pressure readout method in which single Eu${}^{2+}$ ions doping based on fluorescence intensity ratio (FIR) pressure measurement is realized in designed materials. Meanwhile, the measured full width at half maximum (FWHM) as an indicator of pressure sensor performance also reveals that the sensing performance is d FWHM/d P ≈ 1.23 nm GPa${}^{-1}$ and d FWHM/d P ≈ 0.84 nm GPa${}^{-1}$ for Eu${}_{Sr}$ and Eu${}_{Ca}$ positions, respectively. Additionally, the structural stability of the phosphor is confirmed by in situ Raman spectrum. The above results indicate that the Li${}_4$SrCa(SiO${}_4$)${}_2$:0.04Eu${}^{2+}$ phosphor is a good candidate for multi-mode optical pressure sensors. (© 2023 Wiley‐VCH GmbH)