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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Nanostructures, Nanostructuring and Nanosized Soft Matter
CPP 37.5: Talk
Wednesday, March 29, 2023, 16:00–16:15, MER 02
Size matters: Size Effects on Surface Chemistry and Raman Spectra of Sub-5 nm Oxidized High-Pressure High-Temperature and Detonation Nanodiamonds — •Bernhard Schummer1 and Stepan Stehlik2 — 1Fraunhofer Development Center X-ray Technology, 90768 F*urth, Germany — 2Institute of Physics of the Czech Academy of Sciences, 162 00 Prague 6, Czechia
Materials with very small dimensions of a few nanometers is of major importance for fundamental science as well as innovative applications. Those nanomaterials show different effects like quantum size effects, structural transformation or phonon-confinement effects. It has been predicted theoretically that nanodiamonds (NDs) have a structural transformation and phonon-confinement effect below 3 nm in size. Here, we investigate how size effects the surface chemistry, microscopic structure, and Raman scattering of high-pressure high-temperature (HPHT) and detonation nanodiamonds (DNDs) between 2 to 3 nm. The particle size and particle size distribution (PSD) of those different fractions was analyzed with dynamic light scattering, analytical ultracentrifugation, small-angle X-ray scattering, X-ray diffraction, and transmission electron microscopy as complementary techniques. Comprehensive comparison of detonation and pure monocrystalline HPHT NDs reveals effects of diamond core size and defects, chemical and temperature (in)stability, and limitations of current phonon confinement models.