Origin of blue photoluminescence from colloidal silicon nanocrystals fabricated by femtosecond laser ablation in solution.
Nanotechnology
; 27(32): 325702, 2016 Aug 12.
Article
em En
| MEDLINE
| ID: mdl-27348227
ABSTRACT
We present a detailed investigation into the origin of blue emission from colloidal silicon (Si) nanocrystals (NCs) fabricated by femtosecond laser ablation of Si powder in 1-hexene. High resolution transmission electron microscopy and Raman spectroscopy observations confirm that Si NCs with average size 2.7 nm are produced and well dispersed in 1-hexene. Fourier transform infrared spectrum and x-ray photoelectron spectra have been employed to reveal the passivation of Si NCs surfaces with organic molecules. On the basis of the structural characterization, UV-visible absorption, temperature-dependent photoluminescence (PL), time-resolved PL, and PL excitation spectra investigations, we deduce that room-temperature blue luminescence from colloidal Si NCs originates from the following two processes (i) under illumination, excitons first form within colloidal Si NCs by direct transition at the X or Γ (Γ25 â Γ'2) point; (ii) and then some trapped excitons migrate to the surfaces of colloidal Si NCs and further recombine via the surface states associated with the Si-C or Si-C-H2 bonds.
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Coleções:
01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article