Whittaker Luisa, Jaye Cherno, Fu Zugen, Fischer Daniel A, Banerjee Sarbajit
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, USA.
J Am Chem Soc. 2009 Jul 1;131(25):8884-94. doi: 10.1021/ja902054w.
The first-order metal-insulator phase transition in VO(2) 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 VO(2) to nanoscale dimensions. A simple hydrothermal protocol yields anisotropic free-standing single-crystalline VO(2) nanostructures with a phase-transition temperature depressed to as low as 32 degrees C from 67 degrees C in the bulk. The observations here point to the importance of carefully controlling the stoichiometry and dimensions of VO(2) nanostructures to tune the phase transition in this system.
VO₂中的一阶金属-绝缘体相变的特征是电导率和光透射率在超快时间内发生几个数量级的变化，这使得这种材料成为制造光学限幅元件、热致变色涂层和莫特场效应晶体管的有吸引力的候选材料。在此，我们证明了通过将VO₂缩放到纳米尺度尺寸，可以调节相变温度和滞后现象。一种简单的水热方法可产生各向异性的独立单晶VO₂纳米结构，其相变温度从体相中的67℃降低至低至32℃。此处的观察结果表明，仔细控制VO₂纳米结构的化学计量和尺寸对于调节该系统中的相变非常重要。
