Paper NS-MoM3
Hot-wire Chemical Vapor Deposition of Tungsten Oxide Nanoparticles for Use in Energy Applications

Monday, October 18, 2010, 9:00 am, Room La Cienega

Crystalline tungsten oxide nanoparticles were synthesized by hot-wire chemical vapor deposition (HWCVD). These materials are being examined for use in numerous energy related applications including electrochromic windows and fuel cells. It is possible to tune the particle morphology by changing key synthesis parameters including filament temperature, substrate temperature, and oxygen partial pressure. The resulting nanostructures are characterized by a number of techniques including transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The dependence of nanoparticle size and morphology will be described both as a function of HWCVD synthesis conditions as well as post-deposition annealing treatments. The resulting nanoparticles are suspended in solution and used to form thin films on transparent conducting oxide coated glass substrates using an ultrasonic spray deposition process. Ultrasonic spray coating is a cost effective, scalable deposition process that offers an excellent route to achieve large-scale implementation of electrochromic films. Important ultrasonic spray variables include substrate temperature, precursor concentration, carrier solvent and other parameters related to solution atomization. The electrochromic properties of these films were characterized by performing cyclic voltammetry in registry with in situ measurements of optical transmission. Particular attention is paid to optimizing performance metrics such as coloration efficiency and cycling stability. Using the measurements described above, we will evaluate the important process-structure-performance relationships in these systems.