Dual Luminescence of Eu ²⁺ -Activated BaHfO ₃ Perovskites for Effective Pressure and Thermal Sensing

The pursuit of dual-mode pressure–temperature sensors via the luminescence intensity ratio (LIR) technique demands materials with decoupled, responsive emission bands. We demonstrate an Eu 2+ -activated BaHfO 3 perovskite utilizing two distinct Eu 2+ emissions: 5d–4f transitions (∼470 nm) and impurity-trapped exciton (ITE) luminescence (∼590 nm), in which both pressure and temperature sensing operate through ratiometric analysis of these dual bands. As a pressure sensor, the material achieves a relative sensitivity S r ( P ) of 6.5% kbar –1 at 30 kbar via pressure-modulated intensity redistribution between the Eu 2+ and ITE bands. As a thermal sensor, it exhibits a thermal sensitivity S r ( T ) above 1% K –1 over a wide temperature range (<70 to ∼180 K), enabled by the competitive temperature dependence of the two emission bands. Operating across 0–70 kbar and 70–200 K, this work resolves the unusual dual luminescence in BaHfO 3:Eu 2+, revealing ITE as the origin of the 590 nm band. By exploiting the 5d-ITE dual-emission mechanism, we established a unified LIR platform for spatially resolved pressure–temperature quantification, providing new insights into utilizing anomalous luminescence for both pressure and temperature sensing.