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. [10.1002/smll.200800066]

Alkyl-functionalized oxide-free silicon nanoparticles: Synthesis and optical properties

De Cola L.;
2008

Abstract

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.
optical spectroscopy; silicon nanoparticles; surface modification; synthesis; XPS analysis
Settore CHIM/03 - Chimica Generale e Inorganica
SMALL
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/791203
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