Multi-Modal Luminescence Manometer Based on Cr3+ Ions Luminescence in Doped Li3Sc2(PO4)3
Authors: Szymczak Maja , Jaśkielewicz Julia , Runowski Marcin , Xue Junpeng , Mahlik Sebastian , Marciniak Lukasz 
Published: December 2024

The necessity for precise pressure monitoring, coupled with the capability to monitor pressure values in real-time, is paramount. Consequently, recent years have witnessed a notable surge in research aimed at enhancing the quality of pressure sensors, as well as the exploration of novel technological solutions, owing to the rapid advancement in process automation. Sensors leveraging the luminescence response of luminophores show great promise, as evidenced by numerous studies showcasing the remarkable potential of luminescent thermometers. The luminescence characteristics of phosphors are influenced not only by temperature but also by pressure, presenting an opportunity to exploit this phenomenon in pressure sensing. To date, there have been relatively few studies reporting on luminescence-based pressure sensors, with most of them primarily focused on monitoring the spectral position of lanthanide ions emission bands, and less frequently of transition metal ions. The latter, however, due to their heightened sensitivity to variations in the strength of the crystal field affecting the transition metal ion, offer the prospect of designing highly sensitive luminescent pressure sensors. By exploring alternative approaches beyond those reliant solely on spectral shift of emission band, it becomes feasible to enhance both the precision and accuracy of pressure measurements. This assertion finds validation in the development of luminescent ratiometric pressure sensors, as evidenced by reported so far. [1,2]

In line with this, we have proposed an optical pressure sensor based on the luminescence of Cr3+ ions in doped Li3Sc2(PO4)3 [2]. An invaluable advantage of the proposed sensor lies in its ability to operate in three distinct readout modes: (1) ratiometric, based on the LIR parameter, (2) relying on the spectral shift of the emission band, and (3) utilizing the variation in the average lifetime of the excited state. Each approach is grounded on the emission band associated with the 4T2 → 4A2 electronic transition of Cr3+ ions. Owing to the exceptional sensitivity of this transition to pressure-induced changes in the strength of the crystal field affecting Cr3+ ions, the proposed pressure sensor exhibits an exceptionally high sensitivity, e.g. more than 90% GPa-1 in the readout mode based on the average lifetime of the 4T2 state, which is a value surpassing any reported in the literature thus far. Additionally, we have demonstrated the feasibility of obtaining pressure readouts which are independent from temperature variations. Mentioned achievements positions Li3Sc2(PO4)3 as an outstanding candidate for application as a high-sensitivity luminescent pressure sensor in high-pressure environments.

Acknowledgements: This work was supported by the National Science Center (NCN) Poland under project no. DEC-UMO - 2020/37/B/ST5/00164.

[1] T. Zheng, M. Sójka, P. Woźny, I. R. Martín, V. Lavín, E. Zych, S. Lis, P. Du, L. Luo, M. Runowski, Adv. Optical Mater. 2022, 10, 2201055

[2] M. Szymczak, J. Jaśkielewicz, M. Runowski, J. Xue, S. Mahlik, L. Marciniak, Adv. Funct. Mater. 2024, 2314068