Ho ³⁺ ‐doped (K, Na)NbO ₃ ‐based multifunctional transparent ceramics with superior optical temperature sensing performance

Abstract

Abstract Ho 3+ ‐doped (K 0.5 Na 0.5 )NbO 3 ‐based transparent ceramics have been prepared via pressureless solid‐state method. The ceramics possess moderate optical transparency with the energy band gap of ~2.9 eV and submicron‐sized grains (<500 nm). The temperature‐dependent dielectric properties and ferroelectric polarization‐electric field hysteresis loops demonstrate that the ceramics own relaxor‐like characteristics. The up‐conversion photoluminescence and optical temperature sensing properties of the ceramics have been investigated. The temperature dependence of photoluminescence provides a fluorescent method to detect phase transitions, which can be expanded to other ferroelectric systems. The outstanding optical temperature sensitivity (~0.0075/K at 430 K) of the ceramic is higher than many other rare‐earth‐doped ceramics or glasses. These results suggest that the Ho 3+ ‐doped (K 0.5 Na 0.5 )NbO 3 ‐based transparent ceramics are promising lead‐free transparent materials for multifunctional applications, especially in temperature sensing devices.