Exploring the Potential Applications of Lanthanide-Based Double Perovskite in Remote Pressure and Temperature Sensing

Remote optical sensing with nondestructive, fast, and accurate detection capabilities is a powerful noncontact method widely used in natural, industrial, and biological fields. In this work, Cs₂NaErCl₆ double perovskite was synthesized via a hydrothermal method. The pressure-dependent photoluminescence (PL) lifetime of Er³⁺ in the range of 0-20 GPa was investigated, demonstrating its potential for pressure monitoring. The high-pressure relative sensitivity (S_R) is ∼18.45% GPa^-1. Temperature measurements were conducted using the fluorescence intensity ratio (FIR) of the thermal couple energy level (TCEL) and the nonthermal couple energy level (NTCEL) of Er³⁺ across a temperature range of 100-660 K, with a maximum S_R of 5.36% K^-1. By combining MXene with Cs₂NaErCl₆ and recording the FIR of Cs₂NaErCl₆ under 1550 nm excitation, the photothermal conversion temperature of MXene can be accurately determined. These findings highlight the potential of Cs₂NaErCl₆ for remote pressure and temperature sensing, particularly in the biomedical field.