The first-order metal insulator phase transition in VO2 is characterized by an ultrafast several orders of magnitude change in electrical conductivity and optical transmittance, which makes this material an attractive candidate for the fabrication of optical limiting elements, thermochromic coatings, and Mott field-effect transistors. Here, we demonstrate that the phase transition temperature and hysteresis can be tuned by scaling VO2 to nanoscale dimensions. A simple hydrothermal protocol yields anisotropic freestanding single-crystalline VO2 nanostructures with a phase-transition temperature depressed to as low as 32 C from 67 C in the bulk. The observations here point to the importance of carefully controlling the stochiometry and dimensions of VO2 nanostructures to tune the phase transition in this system.
Citation: Journal of the American Chemical Society
Pub Type: Journals
Vanadium oxide, metal-insulator phase transition, monoclinic, tetragonal, NEXAFS