Synthesis of Luminescent Silicon Nanopowders Redispersible to Various Solvents

Graduate School of Material Science, University of Hyogo, 3-2-1, Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan.
Langmuir (Impact Factor: 4.46). 07/2005; 21(14):6324-9. DOI: 10.1021/la050346t
Source: PubMed


Silicon nanopowder with a narrow size distribution was synthesized by a simple method, in which amorphous SiO(x) (x < 2) powder as starting material was annealed at high temperature and then etched by hydrofluoric acid (HF). Si nanoparticles thus obtained exhibited emission in the ultraviolet and visible regions under excitation at an energy corresponding to the direct band-gap transition. At the same time, they could be redispersed in various organic solvents such as octanol, toluene, etc., without surfactants or capping molecules on particle surfaces. X-ray diffraction and Fourier transform infrared spectroscopy were used to follow the change of components in the sample during annealing and HF etching processes, and the size distribution and dispersion morphology of the nanoparticles in different solvents were revealed by transmission electron microscopy analysis.

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    • "Excellent spectroscopic properties, such as high quantum yield, broad absorption window, and narrow fluorescent wavelength, contribute to a rapid development in Si QD research [1]. Nontoxicity to the environment and the use of an economic source material are other two merits for the application of Si QDs in optoelectronics [2,3], solar energy conversion [4,5], biology [6-8], splitting water [9], etc. Si QDs can be prepared using a variety of techniques such as wet chemical reduction [10-18], metathesis reaction [19], disproportionation reaction [20,21], thermal annealing of Si-rich SiC [22], electrochemical etching [23], plasma synthesis or plasma-enhanced chemical vapor deposition (PECVD) [24-27], and high-temperature hydrogen reduction method [28-32]. Because Si QDs are chemically active, their surface should be passivated for further use. "
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