Effect of sol-age on the surface and optical properties of sol-gel derived mesoporous zirconia thin films

Manish Kumar,G B Reddy

doi:10.1063/1.3590744

Abstract

Mesoporous ZrO2 thin films have been deposited by a modified sol-gel dip coating technique using HCl as catalyst. Effects of sol-age on the surface and on the optical properties are studied. Transmission electron micrographs of the films reveal the pore dimensions in mesoporous regime. A strong correlation in surface topography with sol-age has been observed where increase in sol-age induces a systematic enhancement in the value of root mean square roughness of the films. Optical study shows that deposited films have high transmittance and an enhancement of 5.6 times in porosity in films prepared with sol-age of 10 days with respect to that of 1 day. Band gap estimation by Tauc's plots of films is observed to 5.74 eV, which shows invariance with the sol-age.

Highlights

Mesoporous films have recently attracted much attention for a wide range of applications i.e. microelectronics,[1] hosts for nanostructures[2,3,4] and low dielectric constant materials.[5]
ZrO2 films are dipped in aqueous solution of methylene blue (MB) and change in A of solution is measured before and after the immersion of films prepared with sol age of 1, 3 and 10 days and plotted in Fig. 7(a) with curves (i), (ii), (iii) and (iv), respectively
The work presented in this paper provides further information on the synthesis process and role of sol-age

Summary

INTRODUCTION

Mesoporous films have recently attracted much attention for a wide range of applications i.e. microelectronics,[1] hosts for nanostructures[2,3,4] and low dielectric constant materials.[5]. Materials with pore diameter in mesoporous regime (between 2 and 50 nm) have been proven to be ideal for hosting the noble metal nanostructures for plasmonic applications, since in this size regime metal nanostructures exhibit excellent size dependent properties. Such fine requirements place strong demands on manipulation of microstructure to obtain controlled porosity and average pore size in mesoporous range with narrow size distribution. As reported by Borras et al.12may induce undesired thermal effects in the inorganic matrix during the formation of porous films These limitations have forced researchers to develop porous films by sol-gel method, which is regarded as a relatively promising method to obtain controlled porosity by controlling the processing steps.[8,13]. The role of pH of starting polymeric sol and duration of sol-age on the microstructure, surface and optical properties of films has been presented with the emphasis on controlled porosity

EXPERIMENTAL

AND DISCUSSION

Findings

CONCLUSIONS