Synergistic Role of Model‐Independent and Model‐Dependent Approaches for Determining Size and Shape of Au Nanostructures Using SAXS

Abstract

The main objective of this study is to showcase the use of synergistic utilization of model‐independent and model‐dependent approaches for analyzing small angle X‐ray scattering (SAXS) data to determine the shape and size of different nanostructures viz. spherical, nanorod, and core‐shell. Herein, different gold nanostructures viz. spherical, nanorod, and core‐shell are synthesized and analyzed using SAXS. First, the SAXS data are analyzed using Guinier law, PDDF (pair–distance distribution function) plots, double logarithmic plots, and electron density curves to get primary information about the size and shape of nanostructures. This information is utilized for choosing an appropriate model and initial input parameters for fitting the SAXS data. The observations obtained from SAXS studies are compared with transmission electron microscopy and UV–vis spectroscopy. It is believed that this study will help in understanding the analysis of SAXS data using a systematic and synergistic approach of utilizing the two methods. It is believed that the study will further add to the understanding of the technique as an alternative approach for transmission electron microscopy.

Mineral fusion via dehydration-induced residual stress: from gels to ceramic monoliths

“…Under ambient conditions, the aqueous solutions of two common salts, FeCl3 and (NH4)6Mo7O24, were mixed and centrifuged to render a greenish PIG (with 80 wt% water, Figure S1) of amorphous Fe(OH)(MoO4)•H2O (Figure 1e) via the olation of [Fe(OH)(H2O)n] 2+ and (MoO4) 2− . The Small-angle X-ray scattering (SAXS) characterisation revealed the form factor I(q)∝q −2 (Figure 1i) (where q is the scattering length vector: q = 4πsin(θ)/λ, with λ being the wavelength of the radiation and θ the deflection), implying a lamellar shape of the nanoparticles in the PIG 22 , and a bell-shaped P(r) (pairdistance (r) distribution function) (Figure 1j) with a maximum shifted to a distance smaller than Dmax/2, confirming that the nanoparticles were flat and approximately 25 nm in diameter, which are results consistent with the transmission electron microscopy (TEM) observation (Figure 1a). And these amorphous flat nanoparticles tend to assemble into larger aggregates of approximately 50-300 nm (Figure 1k).…”