Pai Geng1 Jingwei Wang1 Run Shi1 Nianduo Cai1 Ouwen Peng1 Dejun Kong1 Wenkai Ouyang1 Chun Cheng1

1, Southern University of Science and Technology, Shenzhen, , China

Temperature measurement is essential to a variety of scientific experiments and technological application. Quantities of thermometers which were used for thermal sensing at macroscopic length scales have been developed and produced. However, it’s still challenging to do the in situ and quantitative temperature measurement of nanoscale objects with a convenient and simple approach. In this work, we demonstrate a new type of optically-readable VO2 nanowire-based thermometer1. By changing the conditions of reaction, the hydrothermal synthesis of intrinsic H-doping VO2 (M) nanowires has been achieved. During the hydrothermal reactions, the concentration of hydrogen doping can be adjusted by changing the concentration of reductive agent and filling ratio. After annealing treatment, the dopants or vacancies in as-grown hydric VO2 nanowires can be redistributed or eliminated. Because of the hydrogen doping through hydrothermal fabrication and the hydrogen engineering via a post-annealing process, the single-domain VO2 nanowires obtains a unique axially-gradient phase transition behavior, which makes the advanced thermometer possible. The optically-readable VO2 nanowire-based thermometer is user-friendly and appropriate to microscopic size. What’s more, it also has ultra-high relative sensitivity (≈17.4%/K) and temperature resolution(≈0.026K) via optical microscope. It can even achieve an extremely high resolution of (≈10-5K) when combining with transmission electron microscope (TEM). The advanced thermometer we demonstrated enables the sensitive monitoring of the thermal environment of small space or the temperature of even nanoscale structure which greatly facilitates the nanoscale scientific experiments and technological application.

(1)Guo, H.; Khan, M. I.; Cheng, C.; Fan, W.; Dames, C.; Wu, J.; Minor, A. M. Vanadium Dioxide Nanowire-Based Microthermometer for Quantitative Evaluation of Electron Beam Heating. Nat. Commun. 2014, 5.