Temperature invariant lifetime based luminescent manometer on Mn4+ ions

Abstract

Luminescent manometry enables remote pressure readout with unprecedented spatial and pressure resolution. The need to image pressure in a temperature-invariant manner imposes the search for new solutions that offer such capabilities. In this study, we present an approach that enables remote pressure sensing using the luminescence kinetics of Mn⁴⁺ ions in SrGdAlO₄. The uniqueness of this solution is related to the pressure induced prolongation of the lifetime of the ²E level of Mn⁴⁺ ions resulting from a change in the covalency of the Mn⁴⁺–O²⁻ bond. Taking the advantage of this effect, the luminescence decay time was increased from 1.44 ms to 2.14 ms when the pressure was changed from ambient to 7.6 GPa. This allowed the development of a luminescent manometer with a maximum relative sensitivity of 7.85%/GPa at 3 GPa and sensitivities above S_R > 5%/GPa in the pressure range of 1–7.6 GPa. Moreover, in the temperature range of 260–365 K, the lifetime value was independent of temperature changes, enabling a temperature invariant manometric factor of 134.