The microstructure properties of the sol-gel derived TiO2 films were studied by the atomic force microscopy (AFM). The films were prepared by dip coating process. The optical properties of the films were explained on the basis of the microstructure of the films

Vanadium pentoxide films were prepared by evaporation followed by annealing posttreat-ment in 02 atmosphere. Lithium was inserted electrochemically from an electrolyde into vana-dium pentoxide films so that Li, V205 was formed. The structure of the posttreated sampleswas determined by XRD and infrared reflectance was measured by FTIR for as-grown andlithiated films, respectively. The experimental results have shown that V2Os thin films havesome infrared absorption peaks located at 982, 824, 527 and 504cm-1, and the infrared vibra-tion bands corresponding to the peaks have a good agreement with the analysis by Abello et al.for polycrystaliine V205, and there is a obvious influence of lithium insertion on the infraredvibration properties which may be reconciled with the lattice change such as expansion andcontraction.

A relatively new method to adjust refractive index of nano-porous silica films rapidly and continuously is reported. The thinfilms were prepared with the base:acid two-step catalytic sol-gel process and the dip-coating method. The structure, reflectivespectra and refractive index of the films were analyzed with TEM, AFM, SEM, spectrophotometer, and ellipsometery, respectively. The experimental results have shown that the base: acid two-step catalysis can adjust the refractive index of thenano-porous silica films from 1.18 to 1.42 rapidly and continuously. And a broadband antireflective coating made with themethod has very low reflectance. The average reflectance of the coated glass in the solar energy spectrum decreases to 1.5% from 7% of the glass.

To control structure of nano-porous silica films effectively, a base/acid two-step catalytic sol-gel process was investigated. The nano-porous structure and IR absorption of the thin films were characterized by means of FE-SEM, AFM, SEM, FTIR, and ellipsometry, respectively. The experimental results have shown that the base/acid two-step catalysis can adjust the refractive index of the films from 1.18 to 1.41 rapidly and continuously. With a change of the experimental conditions, the frequency shift of the v4 (TO3) peak of FTIR absorption to a lower wave number indicates a decrease in the average Si-O-Si bridging angle. A reduction of FWHM of the peak reveals a narrow distribution of the Si-O-Si bridging angle. These results suggest that influence of the experimental conditions on the FTIR absorption of the nano-porous silica films is attributed to a change of silica particle shape and state of aggregation of the particles in the films.