Synthesis of Luminescent Silicon Nanopowders Redispersible to Various Solvents

Abstract

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.

The evolution of pseudo-spherical silicon nanocrystals to tetrahedra, mediated by phosphonic acid surfactants

“…This is consistent with observations from other previously reported methods of silicon nanoparticle production. [26,27] XRD analysis from samples collected from control experiments, where TOP, DPS or CO 2 were omitted from a typical synthesis, found that no crystalline material was formed in their absence. Without the use of TOP in conjunction with the supercritical fluid, large lumps of amorphous silicon could be produced.…”

Optical Properties of Nanostructured Silicon

“…The other methods to produce porous silicon-related nanostructures include reactive sputtering [17], solgel techniques [18], SiO 2 implantation [19], selfassembly [20], growth in inverse micelles [21,22], laser ablation [23], thermal annealing [24][25][26], thermal vaporization [27,28], decomposition of silanes [29][30][31][32][33], solution synthesis [34][35][36], hybrid techniques [37], and plasma processing [38][39][40].…”

Surface Passivation and Functionalization of Si Nanocrystals

“…The hydrosilylation approach has led to a substantial control over Si-nc hydrophilicity ultimately rendering them soluble in a variety of organic (see Figure 6.4) [14] and in some cases aqueous solvents [13,15]. FT-IR spectra of functionalized particles clearly show characteristic features of the surface-bonded organic moieties, residual hydride termination, and some surface oxide that admittedly masks the absorptions from the SiÀC linkage at 1083 cm À1 (see Figure 6.4) [11,16].…”