CdSe/ZnSe quantum structures grown on GaAs~001! by molecular-beam epitaxy were systematically investigated by high-resolution x-ray diffraction and high-resolution transmission-electron microscopy. Half of the initial Cd deposit redesorbs when migration-enhanced epitaxy is used instead of conventional molecular-beam epitaxy for the overgrowth of the CdSe by ZnSe. This result is explained by a s...

Composite photocatalysts are crucial for photocatalytic hydrogen evolution. In this work, ZrO2/CdSe-diethylenetriamine (ZrO2/CdSe-DETA) heterojunction nanocomposites synthesized, and efficiently stably catalyzed evolution under visible light. X-ray photoelectron spectroscopy (XPS) high resolution transmission electron microscope (HRTEM) confirm the formation of heterojunctions between ZrO2 (ZO)...

The evolution of CdSe quantum dot (QD) formation on ZnSe was investigated on a series of samples grown by MBE, with nominal CdSe coverages ranging from 1.1 to 2.6 monolayers (ML). Micro-PL data suggest strongly con"ned zero-dimensional excitons even for coverages as low as 1.1 ML. PL and micro-PL data show emission from the QDs as well as from an accompanying 2 D layer; the temperature dependen...

In this paper, CdSe nanocrystal dissolution in an aqueous solution was studied. It was found that light is a key factor affecting the dissolution of nanocrystals. In the presence of light, the electrons generated from CdSe nanocrystals reduce water to hydrogen and hydroxide ions (OH-) while photo-generated holes oxidize CdSe to Cd2+ and elemental Se. The dissolution was accelerated in an acidic...

We report a synthesis of highly luminescent (CdSe)ZnS composite quantum dots with CdSe cores ranging in diameter from 23 to 55 Å. The narrow photoluminescence (fwhm e 40 nm) from these composite dots spans most of the visible spectrum from blue through red with quantum yields of 30-50% at room temperature. We characterize these materials using a range of optical and structural techniques. Optic...

A key consideration for the efficient operation of hybrid solar cells based upon conjugated polymers and inorganic semiconductor nanocrystals is charge transport in the nanocrystal phase. Here we report the results of a study into the charge transport kinetics of polymer/nanocrystal solar cells based on blends poly(3-hexylthiophene) (P3HT) with either CdSe nano-dots or CdSe nano-tetrapods. Tran...

Fluorescent semiconductor nanoparticles, or quantum dots, have potential uses as an optical material, in which the optoelectronic properties can be tuned precisely by particle size. Advances in chemical synthesis have led to improvements in size and shape control, cost, and safety. A limiting step in large-scale production is identified to be the raw materials cost, in which a common synthesis ...

Highly ordered TiO2 nanotube arrays (TiO2-NTAs), with a uniform tube size on titanium substrate, were obtained by means of reoxidation and annealing. A composite structure, CdSe quantum dots@TiO2 nanotube arrays (CdSe QDs@TiO2-NTAs), was fabricated by assembling CdSe quantum dots into TiO2-NTAs via cyclic voltammetry electrochemical deposition. The X-ray diffractometer (XRD), field-emission sca...

A transferable force field for the PbSe-CdSe solid system using the partially charged rigid ion model has been successfully developed and was used to study the cation exchange in PbSe-CdSe heteronanocrystals [A. O. Yalcin et al., "Atomic resolution monitoring of cation exchange in CdSe-PbSe heteronanocrystals during epitaxial solid-solid-vapor growth," Nano Lett. 14, 3661-3667 (2014)]. In this ...

Reaction of 3-aminopropylsilyl-modified ZnO microrods with trioctylphosphineoxide-coated CdSe/CdS core/shell nanocrystals in THF produces rod-shaped nanoparticle clusters that show directional photoemission that can be tuned with the size of the CdSe nanocrystals. The observed waveguiding effect of these microstructures is due to total internal reflection of light at the cluster-air interface.