Abstract

The interest in silicon nanocrystals (SiNCs) was spurred in the 1990s by Canham’s discovery of the naked-eye-visible, room-temperature light emission of porous silicon [21]. This finding stimulated scientific interest in SiNCs capped with silicon oxide, which can form on the NC surface naturally at ambient conditions. Despite intense research and application prospects in both optoelectronics and nanomedicine, oxide-passivated SiNCs were shown to have some shortcomings, mainly the tendency to agglomerate, poor spectral tunability, and poor stability in the case of porous silicon [155]. To remedy these problems, surface passivation (or functionalization*) via direct covalent attachment of preferably organic monolayers is an excellent alternative to simple oxidation, as known preparation methods do not allow for the lattice-matched core-shell structures common in other semiconductor NCs. The Si–C bond in particular is strong and only weakly polarized [191]. Organic passivation is stable, and, moreover, the attachment of organic groups provides wider versatility of the final product, including tailoring solubility in various solvents, and wider tunability of emission wavelength.