Investigating the Potential of Cr³⁺-Doped Pyroxene for Highly Sensitive Optical Pressure Sensing

Luminescent manometry has gained significant popularity in recent years due to its capability to provide in situ pressure measurements in a remote manner. Therefore, there is a growing need to identify phosphors with pressure-dependent spectroscopic properties that can be utilized to develop highly sensitive pressure sensors operating over a wide pressure range. Hence, we present a novel temperature-invariant luminescent manometer based on Cr³⁺ ion emission in pyroxene Ca_0.8Sr_0.2MgSi₂O₆:Cr³⁺. We utilized two readout modes, including an innovative luminescent pressure sensing ratiometric approach based on the broad emission band associated with the ⁴T_2g → ⁴A_2g electronic transition of Cr³⁺ ions. This approach provided an exceptionally high sensitivity of S_R = 50.7 ± 0.5% GPa^-1 and ensured temperature-independent pressure measurements, thus offering highly reliable readouts. Furthermore, the proposed readout mode, which leverages changes in luminescence kinetics, demonstrated high sensitivity at high pressure at around 5 GPa (S_R ∼ 8 ± 0.2% GPa^-1) surpassing the performance of luminescence kinetics-based manometers reported to date. Consequently, Ca_0.8Sr_0.2MgSi₂O₆:Cr³⁺ emerges as a highly promising phosphor with significant application potential for pressure sensing across a broad pressure range.