Synthesis, upconversion luminescence and optical heating of hexagonal NaGdF4:Yb3+,Er3+

An optical heater based on hexagonal NaGdF4:Yb3+/Er3+ is reported. XRD, SEM and EDS characterization results show that F-/Ln(3+) can not only control the phase composition, particle size and morphology, but also affect the effective doping concentration of Yb3+ and Er3+. When F-/Ln(3+) is 12/1, the strongest upconversion luminescence is obtained. Based on the luminescent temperature sensing behavior of Er3+, the photo-thermal conversion performance was investigated. The results indicate that the temperature of irradiation spot is linearly dependent on the power density, and the photo-thermal responsivity is determined to be 3.3 K.cm(2)/W. Also, it is found that the photo-thermal conversion efficiency can be regulated by changing the Yb3+ doping concentration. Compared with the nano-gold, copper sulfide and carbon nanotubes, the NaGdF4:Yb3+/Er3+ has the triple functions of upconversion luminescence, temperature sensing, and photo-thermal conversion, and may therefore be a promising optical heater for photo-thermal therapy of tumors. (C) 2018 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.