Large-scale preparation of CdS quantum dots by direct thermolysis of a single-sourceprecursor

Abstract

CdS quantum dots (QDs) have been synthesized on a large scale,based on the direct thermolysis of one single-source precursor,(Me4N)4[S4Cd10(SPh)16], in hexadecylamine (HDA). Transmission electron microscopy (TEM) observations showthat the CdS QDs are well-defined, nearly spherical particles. The clear lattice fringes inhigh-resolution TEM (HRTEM) images confirm the crystalline nature of the QDs. Thebroad diffraction in the x-ray diffraction (XRD) pattern and diffuse diffraction rings of theselected-area electron diffraction (SAED) pattern are typical of nanomeric-size particlesand indicative of the hexagonal phase of CdS QDs. The absorption spectra confirmquantum confinement of CdS QDs. The synthesis process for CdS QDs was investigated byultraviolet–visible (UV–vis) absorption spectroscopy. The results demonstrate that thenucleation and growth stages were separated automatically in a homogeneoussystem.