The effects of Tm3+ concentration on upconversion emission and temperature-sensing behavior of Tm3+/Yb3+:Y2O3 nanocrystals were investigated. Blue and red emissions were observed under 980 nm excitation. Both upconversion emissions and the blue to red intensity ratio were found to decrease with increasing Tm3+ concentration. The temperature-sensing performances of the samples were studied, the fluorescence intensity ratio of 1G4(a)→3H6 (477 nm) and 1G4(b)→3H6 (490 nm) transitions from Tm3+ ions was chosen as the thermometric index. The results showed that the sensor sensitivity was sensitive to Tm3+ ion concentration. The maximum sensitivity of ~32 × 10-4 K-1 was obtained for 0.1%Tm3+/5%Yb3+:Y2O3 nanocrystals at 344 K. Moreover, a marked optical induced heating effect was also found in the nanocrystals. The prepared Tm3+/Yb3+:Y2O3 nanocrystals could be used in temperature-sensing probes and in optical heaters.
Keywords: Nanothermometry; Optical induced heating; Rare earth; Upconversion emission.
© 2018 John Wiley & Sons, Ltd.