Optical properties of Ag-doped polyvinyl alcohol nanocomposites: a statistical analysis of the film thickness effect on the resonance parameters

TL;DR

This study investigates how film thickness influences the optical resonance parameters of Ag-doped PVA nanocomposites, using statistical analysis to understand the effects of doping levels and film thickness on optical properties.

Contribution

It introduces a comprehensive statistical analysis of the impact of film thickness and silver doping on the optical resonance behavior of PVA nanocomposites.

Findings

Resonance parameters depend on film thickness.

Doping concentration affects optical properties.

Statistical methods differentiate behaviors of thin and thick films.

Abstract

Nanocomposites made of polymer films embedding silver nanoparticles were prepared by thermal annealing of poly-(vinyl) alcohol films containing AgNO3. Low (2.5% w:w) and high (25% w:w) doping concentration of silver nitrate were considered as well as their effect on the optical properties of thin (30 nm) and thick (300 nm and more) films. The topography and the optical properties (refractive index $n$ and extinction coefficient $k$) of such films were studied by atomic force microscopy and spectroscopic ellipsometry. For a given doping level, the parameters of the surface plasmon-polariton resonance (amplitude, position and width) were shown to be thickness-dependent. Multivariate statistical analysis techniques (principal component analysis and support vector machines) were used to explain the differences in the optical behavior of the thick and thin films.