Solid‐State NMR and DFT Combined for the Surface Study of Functionalized Silicon Nanoparticles. Issue 45 (23rd September 2015)

• Record Type: Journal Article
• Authors: Lee, Daniel; Kaushik, Monu; Coustel, Romain; Chenavier, Yves; Chanal, Myriam; Bardet, Michel; Dubois, Lionel; Okuno, Hanako; Rochat, Névine; Duclairoir, Florence; Mouesca, Jean‐Marie; De Paëpe, Gaël
• Is Part Of: Chemistry. Volume 21:Issue 45(2015)
• Page Start: 16047
• Page End: 16058
• Publication Date: 2015-09-23
• Subjects: density functional theory -- hydrosilylation -- nanoparticles -- NMR spectroscopy -- silicon; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201502687
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Silicon nanoparticles (NPs) serve a wide range of optical, electronic, and biological applications. Chemical grafting of various molecules to Si NPs can help to passivate their reactive surfaces, "fine‐tune" their properties, or even give them further interesting features. In this work, 1 H, 13 C, and 29 Si solid‐state NMR spectroscopy has been combined with density functional theory calculations to study the surface chemistry of hydride‐terminated and alkyl‐functionalized Si NPs. This combination of techniques yields assignments for the observed chemical shifts, including the contributions resulting from different surface planes, and highlights the presence of physisorbed water. Resonances from near‐surface 13 C nuclei were shown to be substantially broadened due to surface disorder and it is demonstrated that in an ambient environment hydride‐terminated Si NPs undergo fast back‐bond oxidation, whereas long‐chain alkyl‐functionalized Si NPs undergo slow oxidation. Furthermore, the combination of NMR spectroscopy and DFT calculations showed that the employed hydrosilylation reaction involves anti‐Markovnikov addition of the 1‐alkene to the surface of the Si NPs. Abstract : Light on the surface : Surface structures of silicon nanoparticles (NPs, see figure), H‐capped and also alkyl‐functionalized, are studied by using solid‐state NMR spectroscopy. DFT calculations of the chemical shifts help to assign resonances so that the hydrosilylation reaction pathway, particular grafting to various surface facets, and the extent of near‐surface oxidation could be elucidated.