Temperature sensing using sulfur-doped carbon nanoparticles

Temperature sensing at micro/nano scale with materials by direct fluorescence excitation is widely used in the recent years. Here, we report the green hydrothermal synthesis of sulfur-doped carbon nano-particles (S-CNPs) from inexpensive precursors such as sucrose and sodium thiosulfate. The resultant SC-NPs exhibit luminescence both in aqueous and solid states. The variation of steadyestate photoluminescence intensity of S-CNPs with temperature is investigated and the sensitivity of S-CNPs solid film with 355 nm excitation is found to be 2.63 x 10(-2) K-1, which is slightly higher than that with 532 nm excitation (2.15 x 10(-2) K-1). The activation energy is found to be 141.87 and 30.7 meV for 355 and 532 nm excitation, respectively. Similarly, the sensitivity of S-CNPs in solution is found to be 7.3 x 10(-3) K-1 and the the range of temperature is wider than physiological range (288-333 K) which suggests that S-CNPs can be used in the biological cells temperature sensing as well. Overall, the results suggest that S-CNPs can be used as nano thermometers. (C) 2018 Elsevier Ltd. All rights reserved.