Synthesis and Characterization of a 1:6 Au−CdSe Nanocomposite

Abstract

Development of synthetic strategies that allow the formation of controlled 3-dimensional architectures composed of discrete ensembles of nanoparticles is a challenging goal. We present a synthetic strategy that allows the preparation of a macroscopic 3-D metal−semiconductor assemblage composed of 6.0-nm Au and 6.0-nm CdSe nanoparticles cross-linked by a bifunctional organic spacer. Optical absorption and electron microscopy imaging, coupled to electron diffraction and energy-dispersive X-ray analysis, indicate a 1:6 Au−CdSe composite that appears to be uniform over a micrometer scale. The 1:6 structure is believed to be a close-packed structure which arises from a combination of soft-sphere packing forces due to van der Waals and steric forces, and thermodynamic forces due to an acid/base controlled selective interaction of the organic headgroup moieties with the nanoparticle surfaces.

Ag2S Quantum Dots Conjugated Chitosan Nanospheres toward Light-Triggered Nitric Oxide Release and Near-Infrared Fluorescence Imaging

“…For the Ag 2 S-CS-SNO nanospheres, the peak at 1735 cm –1 was attributable to the CO stretching of both the carboxylic acid groups at the surface of Ag 2 S QDs and the ester groups in CS-SNO. No obvious absorption peak corresponding to free thiol group (2490 cm –1 ) appeared in the spectrum, suggesting that GSH molecules were bound to the surface of Ag 2 S QDs via the Ag–thiol bond. The nitrogen NMR technique, an effective tool in both organic chemistry and biochemistry, was employed to further confirm the presence of −SNO groups in the Ag 2 S-CS-SNO nanospheres.…”

Interactions between Water-soluble CdSe Quantum Dots and Gold Nanoparticles Studied by UV-Visible Absorption Spectroscopy

“…We suggest that the Au-CdSe aggregation originates from the electrostatic attraction and self-assembly between Au particles and QDs during interfacial interaction. 14,15 The surface of CdSe QDs, capped with thioglycolic acid, has the negative charges at pH 7.0. At higher concentration of PBS, the citrate sodium removed from the surface of Au nanoparticles and the thioglycolic acid desorbed from the surface of CdSe QDs, which resulting in more and more exposed CdSe QDs becoming faced to Au particles.…”

pH-Controlled interfacial assembly and disassembly of highly luminescent blue emitting Zn Cd1−S/dodecylamine complexes

“…For this reason, it is especially important to select suitable methods for the linkage of NCs to produce nanostructured aggregates, or clusters. Accordingly, different bond types, such as covalent [16][17][18][19][20][21][22], vander waals [23], coordinative [24][25][26] and hydrogen bond [27], have been applied. For these nanostructured aggregates, the fixed irreversible functions were obtained.…”