Synthesis, Characterization, and Spectroscopy of Type-II Core/Shell Semiconductor Nanocrystals with ZnTe Cores

Design and synthesis of colloidal nanocrystal heterostructures with tetrapod morphology.

Zinc Chalcogenide Seed-Mediated Synthesis of CdSe Nanocrystals: Nails, Chesses and Tetrahedrons

Systematically shape-controlled synthesis of colloidal semiconductor nanocrystals (NCs) has attracted increasing attention recently for both fundamental and technological interest. The study on the synthesis of colloidal CdSe NCs has given rise to well-developed methods for producing diverse shapes such as rods, wires, cubs and discs. In the current study, we demonstrate the shape evolution of CdSe NCs by using a seed-mediated approach by control reaction temperature and injection methods. The synthesis utilizes small (2.0–3.0 nm) zinc chalcogenide NCs with zincblende structure as seeds for subsequent growth, which results in distinct shapes of nail-shaped, tetrahedron-shaped, chess piece-s…

Assemblies of semiconductor quantum dots and light-harvesting-complex II

Abstract A novel hybrid system composed of fluorescent core/shell semiconductor quantum dots and the light harvesting complex II (LHCIIb), a membrane protein of higher plants, has been assembled. Experiments with different mutants show that hybrid formation can be mediated by a C-terminal His 6 tag attached to the protein as well as by positive charges of the first N-terminal amino acids of LHCIIb. Quenching of the quantum dot fluorescence upon binding of LHCIIb was partially attributed to energy transfer from the quantum dots to LHCIIb.

Water-soluble, cyclodextrin-functionalized semiconductor nanocrystals: Preparation and pH-dependent aggregation and emission properties

Abstract Using peramino-functionalized β-cyclodextrin molecules for phase.transfer of hydrophobic CdSe multishell nanocrystals into water, we obtained hydrophilic nanoparticles with high quantum yield (up to 50%). At pH > 9, the aqueous solution of these nanocrystals remained stable for several months. The nanoparticles showed a strong influence of the pH of the aqueous solution on the emission of the nanocrystals: the quantum yield varied reversible from ∼10% at pH=6 to ∼50% at pH=14, an effect which according to particle size characterization by dynamic light-scattering and asymmetric flow field-flow fractionation has mainly been attributed to reversible partial aggregation of the hydroph…

Synthesis and Characterization of Highly Luminescent CdSe—Core CdS/Zn0.5Cd0.5S/ZnS Multishell Nanocrystals.

We report on the preparation and structural characterization of CdSe nanocrystals, which are covered by a multishell structure from CdS and ZnS. By using the newly developed successive ion layer adhesion and reaction (SILAR) technique, we could gradually change the shell composition from CdS to ZnS in the radial direction. Because of the stepwise adjustment of the lattice parameters in the radial direction, the resulting nanocrystals show a high crystallinity and are almost perfectly spherical, as was investigated by X-ray diffraction and electron microscopy. Also, due to the radial increase of the respective valence- and conduction-band offsets, the nanocrystals are well electronically pas…