2D TiO2 nanosheets for ultrasensitive humidity sensing application benefited by abundant surface oxygen vacancy defects

The 2D TiO2 nanosheets with surface oxygen vacancy defects and large specific surface area exhibit ultrahigh humidity sensing performance, which could be addressed to the surface defects induced increasement of dissociated protons for hopping transportation and the surface area induced acceleration of electrolytic conduction at low and high RH level, respectively.