Electrochromism in
Nickel-Based Oxides
Coloration Mechanisms & Optimization
of Sputter-deposited Thin Films
Uppsala Dissertations from the Faculty
of Science & Technology No. 56

By Esterban Damian Avendano Soto
August 2004
Uppsala University Press
ISBN: 915545996X
140 pages, Illustrated, 6 " x 9 "
$36.50 Paper Original

This is a Ph.D. thesis. Electrochromic properties of sputter-deposited nickel-based oxide films have been studied with a two-fold goal. From a practical point of view, the optical switching performance has been improved by optimizing the deposition conditions and film stoichiometry with respect to oxygen and hydrogen, and further by adding Mg, Al, Si, Zr, Nb or Ta to the films.

From a theoretical point of view, details of the coloration mechanism have been studied by means of electrochemical intercalation (CV, GITT), optical measurements (UV, VIS, NIR and MIR), RBS, XRD, XPS and EXAFS. Optimization of deposition conditions has been illustrated by the example of films made by sputtering of a non-magnetic Ni(93)V(7) % wt. target in an atmosphere of Ar/02/H2. The optimized films exhibit transmittance modulation between 20% and 75% at 18 mC/cm2 charge intercalation.

The remaining problem with nickel oxide and nickel vanadium oxide films is their residual yellow-brown color tint in the bleached state, which disappears as the short-wavelength transmittance increases upon addition of Mg, Al, Zr or Ta. Optimization of deposition conditions by co-sputtering from two targets and the film composition for mixed oxide films has been illustrated by the example of nickel alumminium oxide.

Materials Science

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