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.