Yb3+/Tm3+/Ho3+ tri-doped YPO4 submicroplates: A promising optical thermometer operating in the first biological window

Currently, real-time and accurate temperature monitoring of biological tissues and cells is of significance for many biological applications. Here, a new type of optical thermometer have been designed based on the thermo-responsive fluorescence intensity ratio (FIR) of Ho3+ (F-5(5) -> I-5(8)) to Tm3+ (F-3(3) -> H-3(6)) emission. To explore the possible application in optical thermometry, Yb3+/Ho3+/Tm3+ tri-doped YPO4 submicroplates have been successfully synthesized via a facile hydrothermal route. Interestingly, the asdesigned UC thermometer (operating in the first biological window) exhibits high temperature sensitivity (similar to 8.85% K-1) and good signal discriminability, which may be expected to find promising potential application for accurately detecting temperature of biological tissues. (C) 2017 Elsevier B.V. All rights reserved.