03007nas a2200217 4500008004100000245013800041210006900179260001200248300001200260490000700272520227100279653003002550653002002580653001102600653002302611653002302634100001902657700002102676700002302697856006902720 1995 eng d00aOptical and Electrochemical Characteristics of Niobium Oxide Films Prepared by Sol-Gel Process and Magnetron Sputtering: A Comparison0 aOptical and Electrochemical Characteristics of Niobium Oxide Fil c08/1996 a285-2960 v403 a

Electrochromic niobia (Nb205) coatings were prepared by the sot-gel spin-coating and d.c. magnetron sputtering techniques. Parameters were investigated for the process fabrication of sol-gel spin coated Nb205 films exhibiting high coloration efficiency comparable with that d.c. magnetron sputtered niobia films. X-ray diffraction studies (XRD) showed that the sot-gel deposited and magnetron sputtered films heat treated at temperatures below 450°C, were amorphous, whereas those heat treated at higher temperatures were slightly crystalline. X-ray photoelectron spectroscopy (XPS) studies showed that the stoichiometry of the films was Nb205. The refractive index and electrochromic coloration were found to depend on the preparation technique. Both films showed low absorption and high transparency in the visible range. We found that the n, k values of the sot-gel deposited films to be lower than for the sputtered films. The n and k values were n = 1.82 and k = 3 × 10−3, and n = 2.28 and k = 4 × 10−3 at 530 urn for sot-gel deposited and sputtered films, respectively. The electrochemical behavior and structural changes were investigated in 1 M LiC104/propylene carbonate solution. Using the electrochemical measurements and X-ray photoelectron spectroscopy, the probable electrode reaction with the lithiation and delithiation is Nb2O5 + x Li+ + x e ↔ LixNb205. Cyclic voltametric (CV) measurements showed that both Nb205 films exhibits electrochemical reversibility beyond 1200 cycles without change in performance. “In situ” optical measurement revealed that those films exhibit an electrochromic effect in the spectral range 300 < λ < 2100 nm but remain unchanged in the infrared spectral range. The change in visible transmittance was 40% for 250 nm thick electrodes. Spectroelectrochemical measurements showed that spin coated films were essentially electrochemically equivalent to those prepared by d.c. magnetron sputter deposition.

10aD.C. magnetron sputtering10aelectrochromism10aNiobia10aoptical properties10asol-gel deposition1 aÖzer, Nilgün1 aLampert, Carl, M1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/optical-and-electrochemical02070nas a2200205 4500008004100000245010400041210006900145260002700214520133500241653003201576653002201608653003101630653002601661653002301687653002301710100001901733700002001752700002101772856007101793 1995 eng d00aOptical and Electrochemical Properties of Sol-gel Spin Coated CeO2-TiO2 Films0 aOptical and Electrochemical Properties of Solgel Spin Coated CeO aSan Diego, CAc07/19953 a

The optical and electrochemical properties of sol-gel spin coated Ce02-TiO2 (50% CeO2) films were investigated for electrochrornic applications. The coating solutions were prepared by using mixed organic-inorganic | Ti(OC2H5)4 and Ce(NH4)2 (NO3)6 | precursors. X-ray diffraction studies showed the sol-gel spin-coated films were composed of an amorphous matrix of titanium oxide containing nanocrystallites of cerium oxide. The coating solar transmission value was Ts=0.8 (250 nm thick). The refractive index and the extinction coefficient were derived from transmittance measurements in the UV-VIS-NIR regions. These films had refractive index value of n=2.18 and extinction coefficient value of k=8x10-4 at λ=550 nm. Cyclic voltametric measurements showed reversible electrochemical insertion of lithium ions in a CeO2-TiO2/LiClO4-propylene carbonate electrochemical cell. During cycling the films maintain high optical transmittance. Spectrophotometric and electrochemical investigations performed on CeO2-TiO2 films revealed that these films are suitable as an optically passive counter-electrode in lithium electrochromic devices.

10acerium oxide-titanium oxide10acounter electrode10aelectrochemical properties10aelectrochromic device10aoptical properties10asol-gel deposition1 aÖzer, Nilgün1 aDeSouza, Selmar1 aLampert, Carl, M uhttps://facades.lbl.gov/publications/optical-and-electrochemical-0