Morphology of gold nanoparticles determined by full-curve fitting of the light absorption spectrum. Comparison with X-ray scattering and electron microscopy data

TL;DR

This study introduces a comprehensive spectral fitting model for gold nanoparticles that accurately determines size, shape, and distribution parameters, validated against X-ray scattering and electron microscopy data.

Contribution

The paper presents a novel full-spectrum fitting approach for mixed gold nanoparticle populations, incorporating polydispersity and interface damping effects, validated through multiple characterization techniques.

Findings

Accurate volume fractions and aspect ratio distributions obtained from spectral data.

Model validation shows strong agreement with X-ray scattering and electron microscopy.

Proper accounting for polydispersity is crucial for quantitative analysis of plasmon peaks.

Abstract

UV-Vis absorption spectroscopy is frequently used to characterize the size and shape of gold nanoparticles. We present a full-spectrum model that yields reliable results for the commonly encountered case of mixtures of spheres and rods in varying proportions. We determine the volume fractions of the two populations, the aspect ratio distribution of the nanorods (average value and variance) and the interface damping parameter. We validate the model by checking the fit results against small-angle X-ray scattering and transmission electron microscopy data and show that correctly accounting for the polydispersity in aspect ratio is essential for a quantitative description of the longitudinal plasmon peak.