Multimodal, super-sensitive luminescent manometer based on giant pressure-induced spectral shift of Cr³⁺ in the NIR range

The remote pressure readout is of vital application importance as it will facilitate and in many cases enable rapid diagnostics. For most of the luminescent manometers described to date, the sensitivity of the pressure readout is limited by the relatively small pressure-induced spectral shift of the emission band. In response to this limitation, in this work, we present a super-sensitive and temperature-invariant NIR emitting luminescent manometer based on LiScGeO₄:Cr³⁺. The ⁴T₂→⁴A₂ emission band of Cr³⁺ ions undergoes in this manometer a linear spectral shift with a rate of dλ/dp = 23.63 nm/GPa, which is the highest value reported in the literature to date. In addition, by using a ratiometric approach, this manometer has a relative sensitivity exceeding 120%/GPa. Importantly, the developed optical manometer operates in the NIR spectral region, providing good light permeability in the non-transparent systems, having high absorption in the visible range. Moreover, in the case of high-pressure luminescence experiments, the use of the developed sensor will eliminate spectral overlapping issues, as the vast majority of the organic and inorganic phosphors emitting in the visible range.