Előadó: Datz Dániel (SZFI)
Előadás címe: Experimental and numerical investigations of the near-field scattering of boron nitride based nanomaterials
Dátum: 2023. július 18. kedd, 10.00
Helyszín: KFKI Telephely, I. épület 1. emeleti Tanácsterem
illetve online:
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Összefoglaló:
Boron nitride nanomaterials exhibit interesting optical properties in the mid-infrared region. Near-field infrared spectroscopy opens the way of probing these properties with 10-20 nm spatial resolution. This method is especially suitable for the investigation of small molecules encapsulated in boron nitride nanotubes. In this presentation, I show my results on near-field probing of boron nitride nanotubes in different stages of their filling process. First, the nanotubes have to be cleaned and their caps opened. This process introduces various defects to the nanotube. I show the defect structure of an isolated, multi-walled boron nitride nanotube, demonstrating the nanoscale resolution on truly nano-sized scatterers.
Then, I demonstrate the possibility to investigate the products of chemical reactions between encapsulated molecules in nano-sized cavities in boron nitride nanotubes in-situ with 20 nm spatial resolution. The unique dielectric properties of BNNT resonantly enhances the near field signal allowing the detection of the signal of a small number of molecules.
Lastly, I present a theoretical description of the scattering process based on the extension of the classical Mie theory. In this formalism, the electric field is expanded as the linear combination of spherical harmonics centered around the scattering particles. This so-called multipole reflection theory (MRT) is able to describe the scattering properties of multiple particles in the vicinity of an interface. I show the applicability of the multipole reflection model for near-field calculations by applying it to measurements of boron nitride materials.
