Highly monodisperse silicon nanoparticles (1.57 ± 0.21 nm) are synthesized with a covalently attached alkyl monolayer on a gram scale. Infrared spectroscopy shows that these silicon nanoparticles contain only a few oxygen atoms per nanoparticle. XPS spectra clearly show the presence of unoxidized Si and attached alkyl chains. Owing to the relatively efficient synthesis (yields ≈ 100-fold higher than of those previously reported) the molar extinction coefficient ε can be measured: εmax = 1.7 x 10-4 M-lcm-1, only a factor of 4 lower than that of CdS and CdSe nanoparticles of that size. The quantum yield of emission ranges from 0.12 (C10H21-capping) to 0.23 (C16H 33-capping). UV/Vis absorption and emission spectroscopy show clear vibrational progressions (974± 14cm-1; up to five vibrational bands visible at room temperature), resembling bulk SiC phonons, which support the monodispersity observed by TEM. This was also confirmed by time-resolved fluorescence anisotropy measurements, which display a strictly monoexponential decay that can only be indicative of monodisperse, ball-shaped nanoparticles.
Alkyl-functionalized oxide-free silicon nanoparticles: Synthesis and optical properties / M. Rosso-Vasic, E. Spruijt, B. Van Lagen, L. De Cola, H. Zuilhof. - In: SMALL. - ISSN 1613-6810. - 4:10(2008), pp. 1835-1841.
|Titolo:||Alkyl-functionalized oxide-free silicon nanoparticles: Synthesis and optical properties|
|Parole Chiave:||optical spectroscopy; silicon nanoparticles; surface modification; synthesis; XPS analysis|
|Settore Scientifico Disciplinare:||Settore CHIM/03 - Chimica Generale e Inorganica|
|Data di pubblicazione:||2008|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/smll.200800066|
|Appare nelle tipologie:||01 - Articolo su periodico|