Linear response for temperature sensing achieved by implanting Er3+into the grain boundary of transparent MgAlON ceramic

Fluorescence thermometry is considered one of the most perspective temperature sensing techniques. However, few materials reported could combine a wide operating temperature range with stable and high sensing sensi-tivity. Herein, the fluorescence thermometry based on MgAlON:0.01 at.% Er3+ transparent ceramic was suc-cessfully proposed using the idea of local structural engineering, which distributed the Er3+ uniformly into the grain boundary of MgAlON transparent ceramic. It is demonstrated that the special local environment of Er3+ led to different fluorescence responses from those in crystalline or amorphous structures. Instead of the classic Boltzmann exponential relationship, a highly linear downshift fluorescence intensity ratio of thermally coupled energy levels of Er3+ with temperature was exhibited. A novel and constant absolute sensitivity (0.0156 K-1) was obtained within the tested temperature range (300-573 K). This work reveals the significance of the local structure of the activators in the design of high-performance fluorescence temperature sensors.