Optical Constants of Crystallized TiO2 Coatings Prepared by Sol-Gel Process

Materials

Xiaodong Wang¹  Guangming Wu²  Bin Zhou² 

[1] Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Pohl Institute of Solid State Physics, Tongji University, Siping Road 1239, Shanghai 200092, China;

关键词: sol-gel;    TiO₂ coating;    thermal annealing;    optical constants;   

DOI  :  10.3390/ma6072819

来源: mdpi

【 摘 要 】

Titanium oxide coatings have been deposited by the sol-gel dip-coating method. Crystallization of titanium oxide coatings was then achieved through thermal annealing at temperatures above 400 °C. The structural properties and surface morphology of the crystallized coatings were studied by micro-Raman spectroscopy and atomic force microscopy, respectively. Characterization technique, based on least-square fitting to the measured reflectance and transmittance spectra, is used to determine the refractive indices of the crystallized TiO₂ coatings. The stability of the synthesized sol was also investigated by dynamic light scattering particle size analyzer. The influence of the thermal annealing on the optical properties was then discussed. The increase in refractive index with high temperature thermal annealing process was observed, obtaining refractive index values from 1.98 to 2.57 at He-Ne laser wavelength of 633 nm. The Raman spectroscopy and atomic force microscopy studies indicate that the index variation is due to the changes in crystalline phase, density, and morphology during thermal annealing.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.