Structural and Optical Properties of Sol-Gel Deposited Proton Conducting Ta2O5 Films

Publication Type

Conference Paper

Date Published

09/1995

LBNL Report Number

LBL-37800

Abstract

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.

Conference Name

8th International Workshop on Glasses and Ceramics From Gels

Year of Publication

1995

Conference Location

Faro, Portugal

Other Numbers

UC-1600