Effect of TiCl4 treatment on the refractive index of nanoporous TiO2 films

•The refractive index of nanoporous TiO2 film is controlled by TiCl4 treatment.•A refractive index change as large as 0.45 is obtained with the TiCl4 treatment.•The pore size distributions are consistent with the results of refractive index measurement. We investigate the effect of TiCl4 treatment o...

Full description

Saved in:
Bibliographic Details
Published in:Applied surface science 2015-12, Vol.357, p.659-665
Main Authors: Lee, Jeeyoung, Lee, Myeongkyu
Format: Article
Language:English
Subjects:
Density
Diffraction
Diffraction efficiency
Diffraction gratings
Nanoporous film
Nanostructure
Refractive index
Refractivity
TiCl4 treatment
TiO2
Titanium dioxide
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•The refractive index of nanoporous TiO2 film is controlled by TiCl4 treatment.•A refractive index change as large as 0.45 is obtained with the TiCl4 treatment.•The pore size distributions are consistent with the results of refractive index measurement. We investigate the effect of TiCl4 treatment on the refractive index of a nanoporous TiO2 film. A nanoparticulate TiO2 film prepared on a glass substrate was immersed in a TiCl4 aqueous solution. The subsequent reaction of TiCl4 with H2O produces TiO2 and thus modifies the density and the refractive index of the film. With increasing TiCl4 concentration, the refractive index initially increased and then declined after being maximized (n=2.02 at 633nm) at 0.08M concentration. A refractive index change as large as 0.45 could be obtained with the TiCl4 treatment, making it possible to achieve diffraction efficiency exceeding 80% in a diffraction grating-embedded TiO2 film. For high TiCl4 concentrations of 0.32M and 0.64M, the refractive index remained nearly unchanged. This was attributed to the limited permeability of high-viscosity TiCl4 solutions into the nanoporous films. The measured pore size distributions were in good agreement with the results of a diffraction analysis and refractive index measurement.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2015.09.075