Synthesis of CdS, ZnS, and CdS/ZnS Core/Shell Nanocrystals Using Dodecanethiol

Abstract

We report a new route to synthesize high quality zinc blende CdS and ZnS nanocrystals in noncoordinating solvent 1-octadecene, using dodecanethiol (DDT) molecules as both the sulfur source and surface capping ligands. Different reaction temperatures and Cd(Zn)/DDT molar ratios were tested to optimize the synthesis conditions. Absorption photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) pattern, and transmission electron microscopy (TEM) were used to characterize assynthesized nanocrystals. The narrow half width at the half-maximum on the long wavelength side of the firstexcitonic absorption peak and TEM images demonstrated nearly monodisperse size distributions of asprepared CdS, ZnS, and CdS/ZnS core/shell nanocrystals. Only trap emissions of the nanocrystals were detected when the amount of DDT was excessive, this came from the strong quenching effect of thiol groups on the nanocrystal surfaces. After overcoating with ZnS shells, band-gap emissions of CdS nanocrystals were partially recovered.

CdS/ZnS nanocomposites: from mechanochemical synthesis to cytotoxicity issues

“…The structural analysis of CdS/ZnS nanocomposites is an object of unceasing interest during the recent years [14,15,[30][31][32][33][34]. Among the most interesting aspects of this system ranks the possibility of polymorphous transformations, since both nanocrystals can exist in cubic as well as in hexagonal modifications.…”

“…With the increase of ZnS content, the diffractions shift from those of cubic hawleyite CdS structure to those of cubic sphalerite ZnS structure. All the diffraction peaks are broadened because of the finite size of the nanocrystals [33] as well as due to the structural disorder introduced into sulfides by milling procedure [19]. However, the crystallinity is well-evidenced and based on this the crystallite size was calculated (Fig.…”

Synthesis of CdS Nanocrystals with Different Shapes via a Colloidal Method

“…Different from our previous report, high monomer concentration and high reaction temperature favors the formation of wurtzite CdS nanorods. 4,23 From the XRD pattern, a higher and narrower (002) peak is observed in contrast to other peaks which indicates the extension of crystalline domain along the c-axis. 19 The corresponding selectedarea electron diffraction (SAED) pattern shows seven distinct rings and the calculated d-spacings match well with the interplanar distances of wurtzite structured CdS ( Figure 2 inset), which also could be indexed to a single hexagonal phase.…”

“…[1][2][3][4][5][6] As well known, properties of NCs are severely dependent on their size and shape. For example, one-dimensional (1D) nanorods and nanowires have been observed to exhibit optical properties that are different from those of zero-dimensional (0D) quantum dots.…”

Dual and Multi-Emission Hybrid Micelles Realized through Coordination-Driven Self-Assembly

“…After three freeze-thaw cycles, the mixture was degassed with N 2 and reacted at 70 • C for 20 h. After completion of the reaction, the reaction solution was added dropwise to a large amount of petroleum ether to precipitate, and the obtained precipitate was washed by THF. After repeating this procedure five times, the macromolecular ligands P(MQ-co-St)-b-PNIPAM (Polymer 4) dried under vacuum was obtained [32,33].…”