%0 Conference Paper %B International Symposium on Glass Problems, International Commission on Glass %D 1996 %T Sol-Gel Deposited Electrochromic Films for Electrochromic Smart Window Glass %A Nilgün Özer %A Carl M Lampert %A Michael D. Rubin %X

Electrochrornic windows offer the ability to dynamically change the transmittance of a glazing. With the appropriate sensor and controls, this smart window can be used for energy regulation and glare control for a variety of glazing applications. The most promising are building and automotive applications. This work covers the use of sol-gel deposition processes to make active films for these windows. The sol-gel process offers a low-capital investment for the deposition of these active films. Sol-gel serves as an alternative to more expensive vacuum deposition processes. The sol-gel process utilizes solution coating followed by a hydrolysis and condensation. In this investigation we report on tungsten oxide and nickel oxide films made by the sol-gel process for electrochromic windows. The properties of the sol-gel films compare favorably to those of films made by other techniques. A typical laminated electrochromic window consists of two glass sheets coated with transparent conductors, which are coated with the active films. The two sheets are laminated together with an ionically conductive polymer. The range of visible transmission modulation of the tungsten oxide was 60% and for the nickel oxide was 20%. We used the device configuration of glass/SnO2:F/WO3/polymer/LizNiOxHy/SnO2:F to test the films. The nickel oxide layer had a low level of lithiation and possibly contained a small amount of water. Lithiated oxymethylene-linked poly(ethylene oxide) was used as the laminating polymer. Commercially available Sn02:F/glass (LOF-Tec glass) was used as the transparent conducting glass. We found reasonable device switching characteristics which could be used for devices.

%B International Symposium on Glass Problems, International Commission on Glass %C Istanbul, Turkey %8 09/1996 %G eng %1

Windows and Daylighting Group

%2 LBNL-39852 %0 Conference Paper %B Window Innovations 95 Conference Proceedings %D 1995 %T Sol-Gel Deposited Amorphous Tantalum Oxide and Niobium Oxide Films as Protonic Conductors %A Nilgün Özer %A Carl M Lampert %X

In this work we report on the preparation of tantalum oxide and niobium oxide films by the sol-gel method for use as proton ion conductors in electrochromic devices. Measurement of the proton conductivity was derived from impedence spectroscopy measurements. The proton conductivity for Ta2O5 and NbO5 films was 4.6 x 10-6 Scm-1 and 3.2 x 10-7 Scm-1 respectively. The structural and chemical properties of the films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. These films were found to be amorphous and close to the stoichometry of Ta2O5 and NbO5 respectively. In order to estimate the compatibility of these sol-gel deposited layers as ion conductors for EC devices, we investigated tantalum oxide and niobium oxide films deposited on sputtered WO3 films. Charge balance and coloration characteristics were investigated during voltammetric cycling in a pH 2 liquid electrolyte. Spectral transmittance was measured for colored and bleached conditions. The photopic weighted transmittance change and solar weighted transmittance change were Tp=35.2% - 21.8% and Ts=75.7% - 14.2% for tantala films on tungsten oxide. For niobia on tungsten oxide the values were Tp=85.3% - 35.2% and Ts=75.8% - 28.1%.

%B Window Innovations 95 Conference Proceedings %C Toronto, Canada %8 06/1995 %G eng %L LBL-38526 %1

Windows and Daylighting Group

%2 LBL-38526 %0 Conference Paper %B Am. Optical Society, Technical Digest %D 1995 %T Sol-Gel Deposited Electrochromic Coatings %A Nilgün Özer %A Carl M Lampert %X

Electrochromic devices have increasing application in display devices, switchable minors and smart windows. A variety of vacuum depition technologies have been used to make electrochromic devices. The sol-gel process offers an alternative approach to the synthesis of optical quality and low cost electrochromic device layers. This study summarizes the developments in sol-gel deposited electrochromic films. The sol-gel process involves the formation of oxide networks upon hydrolysis-condensation of alkoxide precursors. In this study we cover the sol-gel deposited oxides of WO3, V2O5, TiO2, Nb2O5 and NiOx.

%B Am. Optical Society, Technical Digest %C Tucson, AZ %V 17 %P 344-347 %8 06/1995 %G eng %L LBL-38527 %1

Windows and Daylighting Group

%2 LBL-38527 %0 Conference Paper %B 8th International Workshop on Glasses and Ceramics From Gels %D 1995 %T Structural and Optical Properties of Sol-Gel Deposited Proton Conducting Ta2O5 Films %A Nilgün Özer %A Carl M Lampert %K electrochromic devices %K optical proterties %K proton conductor %K tantalum oxide %X

Proton conducting tantalum oxide films were deposited by spin coating using a sol-gel process. The coating solutions were prepared using Ta(OC2H5)5 as a precursor. X-ray diffraction studies determined that the sol-gel films, heat treated at temperatures below 400 °C, were amorphous. Films heat treated at higher temperatures were crystalline Ta2O5. The solar transmission values (Ts) of tantala films on glass generally range from 0.8-0.9 depending on thickness. The refractive index and the extinction coefficient were evaluated from transmittance characteristics in the UV-VIS-NIR regions. The refractive index values calculated at λ=550 nm increased from n=1.78 to 1.97 with increasing heat treatment from 150 to 450 °C. The films heat treated at different temperatures showed low absorption with extinction coefficients of less than k=1 x 10-3 in the visible range. Spectrophotometric and impedance spectroscopic investigations performed on Ta2O5 films revealed that these films have protonic conductivity of 3.2 x 10-6 S/cm. The films are suitable for proton conducting layers in electrochromic (EC) devices.

%B 8th International Workshop on Glasses and Ceramics From Gels %C Faro, Portugal %8 09/1995 %G eng %1

Windows and Daylighting Group

%2 LBL-37800