Format

Send to

Choose Destination
See comment in PubMed Commons below
Phys Chem Chem Phys. 2011 Dec 7;13(45):20255-61. doi: 10.1039/c1cp21366k. Epub 2011 Oct 12.

Surface passivated silicon nanocrystals with stable luminescence synthesized by femtosecond laser ablation in solution.

Author information

1
State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, 310027, PR China.

Abstract

We report the synthesis of silicon nanocrystals via a one-step route, namely, femtosecond laser ablation in 1-hexene under ambient conditions. The size of these silicon nanocrystals is 2.37 ± 0.56 nm as determined by transmission electron microscopy. Fourier transform infrared spectra and X-ray photoelectron spectra indicate that the surface of the silicon nanocrystals is passivated by organic molecules and is also partially oxidized by O(2) and H(2)O dissolved in the solution. These silicon nanocrystals emit stable and bright blue photoluminescence. We suggest that the photoluminescence originates from the radiative recombination of electron-hole pairs through the oxide-related centers on the surface of the silicon nanocrystals. The decay rate of the oxide-related surface recombination can be comparable to that of the direct band gap transition. In the excitation and emission spectra, a vibrational structure with nearly constant spacings (0.18 eV) is observed. We propose that the strong electron-phonon coupling between excitons and the longitudinal optical (LO) phonons of the Si-C vibration is responsible for this vibrational structure. The fluctuations in the peak resolution, about ±0.01 eV, are ascribed to the size distribution and presence of Si-O vibrations. These silicon nanocrystals offer stable luminescence and are synthesized through a "green" and simple route. They may find important applications in many fields, such as bioimaging and environmental science.

PMID:
21993573
DOI:
10.1039/c1cp21366k
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Royal Society of Chemistry
    Loading ...
    Support Center