Enhanced piezoelectricity and non-contact optical temperature sensing performance in Er3+ion modified (K,Na)NbO3-based multifunctional ceramics

Rare earth ions doped ferroelectrics have attracted wide attentions due to their multifunction characteristics with both ferroelectric/piezoelectric properties and intriguing photoluminescence performance, which show great prospects for future multifunctional devices. In this work, a novel rare earth Er3+ ion modified potassium-sodium niobate (KNN) based ceramics were elaborately designed and prepared by the conventional solid-state reaction. The microstructure, phase structure, electric properties and photoluminescence performance of the Er3+ ion modified KNN-based ceramics were systematically investigated. Enhanced piezoelectricity (a considerable d33 of exceeding 300 pC/N and a large d33* up to 500 p.m./V) was realized through optimizing the substitution of BaZrO3 by (Er0.5,Na0.5)ZrO3. Both down-conversion and up-conversion photoluminescence emissions were detected in the optimal composition. The temperature-dependent upconversion emissions of the optimal Er3+ modified ceramic sample in the temperature range of 303-573K were verified to be applicable for non-contact optical temperature sensing with a maximum sensitivity Sa of 0.0028 K-1 and a peak relative sensitivity Sr of 0.96% K-1. Moreover, low-temperature sensing performance with a maximum Sr of 16.7% K-1 in the temperature range of 80-280K was also presented based on the temperature-dependent down-conversion emissions. With both decent electrical properties and intriguing photoluminescence performance, the Er3+-modified KNNbased ferroelectrics exhibit good application potential in the future multifunctional optoelectronic devices.