Tailoring of Thermochromic
VO2 Nanoparticles
Bo Brummerstedt Iversen
E-mail: bo@chem.au.dk
Office: 1512-312
Background:
These projects seek to explore various synthesis paths to obtain nanoparticles of the inorganic
material vanadium dioxide, VO2. Furthermore, the product must obtain a particular crystal structure,
the monoclinic one (m-VO2). This crystal phase of VO2 has unique
thermochromic properties, which means that it changes colour upon
heating into a darker crystal phase. The effect is fully reversible and takes
place around 65oC. This has sparked interest in using transparent layers of
m-VO2 nanoparticles in window coatings, with the aim of creating an
automatic sun-shading effect based on the structural transition which is
induced when the window surface heats up in the sun. The task is tricky
since the size of the nanoparticles must be controlled as well as the crystal
structure. Furthermore, the vanadium in VO2 is in an intermediate
oxidation state which can be tricky to stabilize. As such, these projects
require (and teach) synthesis skills as well as
crystallographic understanding.
Techniques/Methods:
Synthesis in near- and supercritical fluids (e.g. autoclave or continuous-flow)
Pyrolysis synthesis, refluxed wet-chemical synthesis
Thermochemical processing in controlled atmospheres
Powder X-Ray Diffraction, Electron microscopy, Elemental analysis, measurements
of physical properties
Project suggestions:
Synthesis of m-VO2 by autoclave, flow-synthesis, reflux-synthesis or pyrolysis
Surface-mediated stabilization of m-VO2 nanoparticles
Post-treatment and resistivity studies of m-VO2 particles or deposited films
Relevant literature:
Nanoceramic VO2 thermochromic smart glass: A review on progress in solution processing, Y. Gao, H. Luo, Z.
Zhang, L. Kang, Z. Chen, J. Du, M. Kanehira, C. Cao, Nano Energy, 1, 2012, 221-246
A facile synthesizing method of vanadium dioxide by pyrolyzing ammonium metavanadate, J. Qi, G. Ning, R.
Hia, M. Tian, S. Liu, Materials Science – Poland, 30(2), 2012, 151-157
A facile process to prepare one dimension VO2 nanostructures with superior metal-semiconductor transition, X.
Xiao, H. Cheng, G. Dong, Y. Yu, L. Chen, L. Miao, G. Xu, Cryst Eng. Comm., 15, 2013, 1095-1106
Review of supercritical fluids in inorganic materials science, Aymonier, C.; Loppinet-Serani, A.; Reveròn, H.;
Garrabos, Y.; Cancell, F. J. Supercritical Fluids 38, 2006, 242-251