Size Controlled Synthesis of Silicon Nanocrystals within Inverse Micelles

Abstract

Alkyl-terminated Si nanocrystals (NCs) are synthesized at room temperature by hydride reduction of SiCl4 within inverse micelles. Highly monodisperse Si NCs (2 – 6 nm) are produced by variation of the cationic quaternary ammonium salts used to form the inverse micelles. Transmission electron microscopy imaging confirms the NCs are highly crystalline, while FTIR spectra confirm that the NCs are passivated by covalent attachment of alkanes, with minimal surface oxidation. The photoluminescence intensity of the Si NCs exhibits an inverse relationship with the mean NC diameter, with a quantum yield of 12 % recorded for 2 nm NCs.

Highly Selective Optical Detection of Fe3+ Ions in Aqueous Solution Using Label‐Free Silicon Nanocrystals

“…The photophysical properties observed closely match our previous reports for Si NCs, implying that the same luminescence mechanism may be responsible: UV illumination above the band gap energy results in efficient exciton generation within the crystalline core, followed by radiationless transfer and radiative recombination at states near the NC surface. This agrees with literature reports that emphasize the importance of surface species in the radiative recombination mechanisms of Group IV NCs.…”

“…Nanocrystal Synthesis : The synthesis of water‐dispersible Si NCs was adapted from previously reported methods . All reagents and solvents were of reagent grade or higher and were used as received.…”

Efficient one-pot synthesis of highly monodisperse carbon quantum dots

“…This single-phase, room temperature method is inspired by our previously reported syntheses of size monodisperse Group IV nanocrystals. 24,25 The overall synthetic procedure is illustrated in Scheme 1. Under inert atmospheric conditions, carbon tetrachloride is dissolved within the hydrophilic interior of a tetraoctyl ammonium bromide (TOAB) reverse micelle; the carbon source material is then readily reduced using lithium aluminium hydride to form hydrogen-terminated CQDs conned within the micelle interior.…”