Thermal sensitivity and stability of NaYF4:Yb3+, Er3+ upconversion nanowires, nanorods and nanoplates

•NaYF4:Yb3+, Er3+ nanowires, nanorods and nanoplates exhibit excellent temperature sensing properties.•All the upconversion particles show high thermal stability.•Thermal sensitivity depends on the particle shapes and sizes.

In this paper, temperature sensing properties of NaYF4:Yb3+, Er3+ upconversion (UC) nanowires, nanorods and nanoplates were studied compared to their corresponding bulk materials. Heating–cooling cycle tests show that the as-prepared samples have high thermal stability. The natural logarithm of intensity ratio (RHS) between 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions of all the samples shows a good linear relation to the inverse temperature, indicating their potential for temperature sensing applications. Based on the exponential relationship between RHS and temperature, the fitted energy difference (ΔE) of 2H11/2 and 4S3/2 energy levels of Er3+ ions depends on the shapes and sizes of UC samples, which leads to improvements of thermal sensitivity of NaYF4:Yb3+, Er3+ particles with the increase of surface to volume ratios.