Diamond-coated ATR prism for infrared absorption spectroscopy of surface-modified diamond nanoparticles
Résumé
Linear antenna microwave chemical vapor deposition process was used to homogeneously coat a 7 cm long silicon prism by 85 nm thin nanocrystalline diamond (NCD) layer. To show the advantages of the NCD-coated prism for attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) of nanoparticles, we apply diamond nanoparticles (DNPs) of 5 nm nominal size with various surface modifications by a drop-casting of their methanol dispersions. ATR-FTIR spectra of as-received, air-annealed, plasma-oxidized, and plasma-hydrogenated DNPs were measured in the 4000–1500 cm$^{−1}$ spectral range. The spectra show high spectral resolution, high sensitivity to specific DNP surface moieties, and repeatability. The NCD coating provides mechanical protection against scratching and chemical stability of the surface. Moreover, unlike on bare Si surface, NCD hydrophilic properties enable optically homogeneous coverage by DNPs with some aggregation on submicron scale as evidenced by scanning electron microscopy and atomic force microscopy. Compared to transmission FTIR regime with KBr pellets, direct and uniform deposition of DNPs on NCD-ATR prism significantly simplifies and speeds up the analysis (from days to minutes). We discuss prospects for in situ monitoring of surface modifications and molecular grafting.
Mots clés
Chemical Reactions
Carbon
Surface
Silicon
Scanning Electron Microscopy
Reflection
Powder
Nanostructure
Microwave Radiation
Layer
Infrared Spectra
Hydrogenation
Fourier Transform Spectrometers
Diamond
nanodiamond
Crystal
Atomic Force Micoscopy
Annealing
Absorption Spectroscopy
Microwave
Nanocrystalline diamond
Chemical Vapor Deposition (CVD)
ATR FTIR
Absorption Spectra
Nanopowder
Electromagnetic Radiation
Electron Microscopy
Thin film
Heat Treatment
Measuring Instrument
Microscopy
Minerals
Nonmetals
Radiations
Semimetals
Spectrum
Spectrometer
Spectroscopy
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