Guide to Nanoparticle Characterization Techniques

06 June 2023

Nanoparticles, with their unique size-dependent properties, have found widespread applications in fields ranging from medicine to electronics.

However, understanding and controlling these properties require precise characterization techniques. In this blog post, we will explore the various techniques used for nanoparticle characterization and how they contribute to advancing nanoscience.

Transmission Electron Microscopy (TEM): Transmission Electron Microscopy is an invaluable technique for investigating the internal structure of nanoparticles. In TEM, a high-energy electron beam is transmitted through the sample, and the resulting image provides details about particle morphology, crystal structure, lattice spacing, and defects. Additionally, TEM allows for elemental analysis using energy-dispersive X-ray spectroscopy (EDS).

Scanning Electron Microscopy (SEM): Scanning Electron Microscopy is a widely used technique for imaging and characterizing nanoparticles. It provides high-resolution images by bombarding the sample with a focused electron beam and detecting the refelcted electrons. SEM allows for visualizing the size, shape, and surface morphology of nanoparticles, providing valuable information for characterization.

Dynamic Light Scattering (DLS): Dynamic Light Scattering, also known as Photon Correlation Spectroscopy, is a technique used to determine the size distribution of nanoparticles suspended in a liquid. By measuring the intensity fluctuations of scattered light, DLS provides information about particle size, polydispersity, and aggregation state. It is particularly useful for characterizing colloidal nanoparticles in solution.

X-ray Diffraction (XRD): X-ray Diffraction is a powerful technique for analyzing the crystalline structure of nanoparticles. By directing an X-ray beam onto the sample, the resulting diffraction pattern reveals information about the lattice spacing and crystal orientation. XRD can be employed to determine the composition, phase purity, and crystallinity of nanoparticles, aiding in material identification and characterization.

Fourier Transform Infrared Spectroscopy (FTIR): Fourier Transform Infrared Spectroscopy enables the identification of functional groups and chemical bonds in nanoparticles. By measuring the absorption and transmission of infrared light, FTIR provides information about the composition, surface chemistry, and molecular interactions of nanoparticles. This technique helps in understanding surface modifications and coatings on nanoparticles.

Atomic Force Microscopy (AFM): Atomic Force Microscopy is a versatile technique used to probe the surface properties of nanoparticles. It utilizes a sharp tip attached to a cantilever, which scans the sample surface. The deflection of the cantilever provides topographical information at nanometer resolution. AFM can measure particle size, height, roughness, and even mechanical properties like adhesion and elasticity.

Surface Plasmon Resonance (SPR): Surface Plasmon Resonance is a label-free technique that provides real-time information about the interaction between nanoparticles and surrounding molecules. It measures changes in the refractive index caused by the binding of analytes to the nanoparticle surface. SPR helps in understanding nanoparticle-protein interactions, drug delivery, and biosensing applications.

Characterizing nanoparticles is essential for understanding their physical, chemical, and biological properties. The techniques mentioned in this blog post, including SEM, TEM, DLS, XRD, FTIR, AFM, and SPR, provide valuable insights into nanoparticle size, shape, structure, surface chemistry, and interactions. By leveraging these characterization techniques, researchers can unlock the full potential of nanoparticles in various fields, leading to innovative applications and advancements in nanoscience.