Upconversion fluorescence property of Er3+/Yb3+ codoped lanthanum titanate microcrystals for optical thermometry

Abstract Optical thermometry technology plays a significant role in plenty of fields owing to its unrivaled properties such as sensitive, noncontact, reliable and so on. In this work, Er3+/Yb3+ codoped lanthanum titanate (La2Ti2O7) microcrystals have been synthesized by solid state reaction for optical thermometry. This novel prepared material for thermometry is based on the fluorescence intensity ratio of thermally coupled levels from upconversion emission under 980 nm excitation. The sensitivity of thermometry is 5.7 × 10−3 K−1, and the input power density is only 8.3 mW/mm2. Furthermore, the result of repeatability test illustrates that the as-prepared microcrystals possess excellent stability at the temperature range from 333 to 553 K. Therefore, these demonstrated advantages of Er3+/Yb3+ codoped La2Ti2O7 microcrystals make it a promising material in optical thermometry area.