Nanocomposites of Gold and Semiconductors

Abstract

This chapter presents a universal phosphine-free synthesis for metal selenide nanocrystals in its first section, which might be served as seeds for the fabrication of semiconductor–gold nanocomposites. In this method, reduction of elemental Se with sodium borohydride in the presence of hydrophobic alkylamines generated hydrophobic alkylammonium selenide species in situ. The phosphine-free Se precursor is highly reactive and suitable for the synthesis of various metal selenide nanocrystals. Its high reactivity is also favorable to derive core–shell CdSe@CdS quantum dots (QDs) in one-pot synthesis, without the need for prior purification of CdSe cores, offering a greener and less expensive route to the large-scale synthesis of metal selenide QDs. In the latter section of this chapter, after review of the literature on recent advances in semiconductor–gold nanocomposites, we focus on the experimental observations on the composite nanosystems consisting of metal sulfide and Au and/or Ag noble metals and aim at addressing the following critical issues: (i) the deposition behavior of noble metals on semiconductor nanocrystals; (ii) the relationship between the morphology of the nanocomposites and the structure of semiconductors; and (iii) the mechanism accounting for the morphology formation of final composite nanoparticles.