Optical method for characterization of nanoplates in lyosol

• Published in: Microelectronic engineering Vol. 108; pp. 121 - 126
• Main Authors: Wojtkiewicz, S., Sawosz, P., Kostecki, M., Sokolowska, A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2013; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Discrete Dipole Approximation; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Graphene; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Light scattering; Light scattering measurement; Liquids; Materials science; Mathematical analysis; Nanocomposites; Nanomaterials; Nanoparticles; Nanoplates; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Physics; Scanning probe microscopes, components and techniques; Specific materials; Nanoplates; Graphene; Discrete Dipole Approximation; Light scattering measurement; Water; Particle size; Nanosheet; Industrial application; Liquid layer; Discrete method; Nanoparticles; Manufacturing processes; Fine particle; Optical method; Angular distribution; Delamination; Scanning electron microscopy; Nanoplate; Approximate method; Layered crystals; Light scattering; Two dimensional model; Electron microscopy; Colloidal suspension; Dipole approximation; Zero band gap semiconductors; Light absorption; Spherical particle
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2013.02.047

[Display omitted] ► The nanoplates have a dual character of light scattering. ► Theoretical light scattering indicatrices of nanoplates have been developed. ► Two-dimensional particles size estimation with the Zetasizer is highly inaccurate. ► Optical method of characterization of nanoplates has been developed and validated. In the recent years, two-dimensional nanoparticles (the nanoplates) have become a subject of intense scientific researches and industrial applications. The liquid exfoliation of layered crystals becomes the most simple and efficient manufacturing method of graphene and layered compounds nanosheets. The primary product of the liquid exfoliation is a lyosol – a colloidal suspension of desired nanoparticles in a fluid. The shape of the produced nanoparticles may be determined with the use of an electron microscopy (SEM). In the case of spherical particles the concentration and the particles size can be assessed by the light absorption and the dynamic laser light scattering (DLS) measurements respectively. We propose an optical method for fast and comprehensive characterization of shape and size of nanoplates in a lyosol. The system makes use of an optical goniometer. It allows to measure angular distribution of intensity of the light scattered on the lyosol sample. The distribution of the intensity (indicatrix) depends on the shape and size of the nanoparticles. We developed a method of theoretical indicatrix calculation of the nanoplates with the use of Amsterdam Discrete Dipole Approximation method. The experimentally measured indicatrix is compared with the theoretical calculations (standardized indicatrices). We observed that the nanoplate has a dual character of light scattering. It can scatter light as a “small” or “big” particle according to the direction of the incident light beam. We have applied the proposed method of characterization for a water suspension of graphene nanosheets. Results of the measurements are in good agreement with particles dimensions assessed with the SEM images and do not fit with the graphene dimensions estimated with the DLS method. It leads to a conclusion that the two-dimensional particles size estimation with the DLS is highly inaccurate.