@article {12195,
	title = {Preparation and Properties of Spin-Coated Nb<sub>2</sub>O<sub>5</sub> Films by the Sol-Gel Process for Electrochemical Applications},
	journal = {Thin Solid Films},
	volume = {277},
	number = {2-Jan},
	year = {1995},
	month = {05/1996},
	pages = {162-168},
	chapter = {162},
	abstract = {<p>The preparation and properties of Nb<sub>2</sub>O<sub>5</sub> coatings made by the sol-gel process were investigated. The films were deposited by spin coating on In<sub>2</sub>O<sub>3</sub>:Sn/glass and quartz substrates from a polymeric solutions of niobia derived from niobium ethoxide. The films were characterized by investigation of the stoichiometry, refractive index, optical transmission, electrochemical behavior, and the microstructure. X-ray diffraction studies showed the films to be amorphous for heat treatments below 450 {\textdegree}C. X-ray photoelectron spectroscopy (XPS) measurement revealed the O:Nb atomic stoichiometry to be 5:2. Cyclic voltammetric measurements showed that the Nb<sub>2</sub>O<sub>5</sub>/1 M LiClO<sub>4</sub>-propylene carbonate system exhibits electrochemical reversibility beyond 1200 cycles without change in performance. In situ UV-Vis-NIR spectroelectrochemical measurement revealed that Nb<sub>2</sub>O<sub>5</sub> films exhibit an electrochromic effect in the spectral range 300\&lt;λ\&lt;2100 nm and remain unchanged in the infrared spectral range. The change in visible transmittance was 40\% for a 250 nm thick electrode. XPS spectra indicate that Nb(V) is reduced to a lower valence state Nb(IV) in a colored state with injected Li<sup>+</sup>. The bronze coloration is due to a simultaneous injection of electrons and Li<sup>+</sup> ions into Nb<sub>2</sub>O<sub>5</sub>. The sol-gel-deposited\&nbsp;Nb<sub>2</sub>O<sub>5</sub> films are useful for cathodically coloring electrochromic electrodes in electrochromic devices.</p>},
	keywords = {Electrochemistry, Niobium oxide, optical properties, X-ray photoelectron spectroscopy},
	url = {http://dx.doi.org/10.1016/0040-6090(95)08011-2},
	author = {Nilg{\"u}n {\"O}zer and Din-Guo Chen and Carl M Lampert}
}
