Pressure-Triggered Spectral Modulation in Mn2+-Doped ZnAl2O4 Phosphors for High-Sensitivity, Broad-Pressure-Range and Multi-Parameter Optical Manometry

Mn²⁺-doped ZnAl₂O₄ phosphors with exceptional pressure sensing capacities are designed to address the limitations of existing luminescent manometers. Excited at 427 nm, the synthesized phosphors exhibit bright green emission from Mn²⁺ with optimal doping content of 2 mol%. The temperature-dependent emission spectra clarify the good thermal stability of the developed phosphors. Moreover, the pressure-dependent Raman spectra and X-ray diffraction results manifest that the studied samples possess great structural stability over the applied pressure range. Furthermore, evident spectral red-shift and broadened emission band are observed in the synthesized phosphors at high-pressure, leading to pressure-induced polychromatic luminescence. Specifically, as pressure arises (i.e., 0–30.70 GPa), the emission band centroid shows red-shift, contributing to a high absolute sensitivity of dλ/dp = 2.12 nm GPa⁻¹, whereas the full width at half maximum (FWHM) of the emission band is increased, resulting in the absolute sensitivity of dFWHM/dp = 0.71 nm GPa⁻¹. Additionally, through analyzing the responses of the color coordinates to pressure, the manometric properties of the designed phosphors are also investigated, yielding a maximum relative sensitivity of 18.34% GPa⁻¹. These findings demonstrate that the designed phosphors are promising candidates for high-sensitivity, broad-range, and multi-parameter optical manometers.