Abstracts Book - IMRC 2018

• SF2-P041
ELECTROCHROMISM OF TiO2-ZnO THIN FILMS DEPOSITED BY DC
REACTIVE MAGNETRON SPUTTERING
Horacio Crotte Ledesma 1 , Pedro Emmanuel Garcia Tinoco 1 , Mario Pérez González 1 , Martin
Ponce Mosso 1 , Sergio Armando Tomás Velázquez 1
1 Centro de Investigación y de Estudios Avanzados del IPN - CINVESTAV, Fisica, Mexico.
Electrochromism of transition metal oxides has been widely used in the
development of smart windows, which are good candidates for energy saving
applications in buildings. In the present work, thin films were deposited on ITOcoated
glass substrates by dc reactive magnetron sputtering using Ti and (Ti) 90 -
(Zn) 10 targets. The influence of the sputtering power, working pressure, and
post-annealing temperature on the physical properties of the films was studied.
The surface roughness was measured by stylus profilometry. X-ray diffraction
measurements showed the amorphous nature of the as-deposited films.
X-ray photoelectron spectroscopy analysis of as-deposited films revealed the
Ti 4+ and Zn 2+ oxidation states corresponding to TiO 2 and ZnO, respectively. The
coloration efficiency was obtained simultaneous measurements of cyclic
voltammetry (CV) and UV-Vis spectrophotometry. The CV experiments were
carried out at room temperature in a three-electrode electrochemical cell, with
the sample as working electrode, and Ag/AgCl and Pt as reference and counter
electrodes. The electrolyte consisted of 0.1 M propionic acid in aqueous
solution. The voltammograms were analyzed for 20 cycles with the applied
voltage varying -1.0 to 0.7 V vs Ag/AgCl and a sweep rate of 10 mV/s. The
coloration efficiency (CE), one of the most important parameters in the
evaluation of electrochromic films, resulted higher for the TiO 2 -ZnO thin films
with respect to pure TiO 2 samples. For samples post-annealed in air, the CE
values decreased as the annealing temperature increased 23 up to 500 °C.
Finally, a dependence of CE on film thickness was demonstrated. This outcome
proves that an appropriate choice of deposition parameters can improve the
electrochromic response of materials.
References:
[1] C.G. Granqvist, Handbook of Inorganic Electrochromic Materials, Elsevier,
Amsterdam, The Netherlands, 1995.
[2] I. Sorar, E. Pehlivan, G.A. Niklasson, C.G. Granqvist, Electrochromism of DC