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Y Charles Cao

Publications and source records attributed to Y Charles Cao.

8 recordsLinked to original sources
PubMed2006

Synthesis of colloidal uranium-dioxide nanocrystals.

In this paper, we have developed an organic-phase synthesis method for producing size-controlled, nearly monodispersed, colloidal uranium-dioxide nanocrystals. These UO2 nanocrystals are potentially important to applications such as nuclear fuel materials, catalysts, and thermopower materials. In addition, we have systematically mapped out the functions of the solvents (oleic acid, oleylamine, and 1-octadecene) in the synthesis, and we found that N-(cis-9-octadecenyl)oleamide-a product of the condensation of oleic acid and oleylamine-can substantially affect the formation of UO2 nanocrystals. Importantly, these results provide fundamental insight into the mechanisms of UO2 nanocrystal synthesis. Moreover, because a mixture of oleic acid and oleylamine has been widely used in synthesizing a variety of high-quality metal or metal-oxide nanocrystals, the results herein should also be important for understanding the detailed mechanisms of these syntheses.

Alkenes↗
PubMed2006

Radial-position-controlled doping in CdS/ZnS core/shell nanocrystals.

In this paper, we report a new doping approach using a three-step synthesis to make high-quality Mn-doped CdS/ZnS core/shell nanocrystals. This approach allows precise control of the Mn radial position and doping level in the core/shell nanocrystals. On the basis of this synthetic advance, we have demonstrated the first example in which optical properties of Mn-doped nanocrystals strongly depend on Mn radial positions inside the nanocrystals. In addition, we have synthesized nanocrystals with a room-temperature Mn-emission quantum yield of 56%, which is nearly twice as high as that of the best Mn-doped nanocrystals reported previously. Nanocrystals with such a high-emission quantum yield are very important to applications such as nanocrystal-based biomedical diagnosis.

Cadmium Compounds↗
PubMed2004

One-pot synthesis of high-quality zinc-blende CdS nanocrystals.

This paper reports a one-pot synthetic method for producing CdS nanocrystals. We have demonstrated that the nanocrystal nucleation and growth stages can be automatically separated in a homogeneous system with the presence of nucleation initiators. Accelerators used for more than 70 years in rubber vulcanization (i.e., tetraethylthiuram disulfides, and 2,2'-dithiobisbenzothiazole) were found to be effective nucleation initiators for CdS nanocrystal synthesis. The as-prepared CdS nanocrystals are highly monodisperse and possess a zinc blende crystal structure. The quantum yield of the band-gap photoluminescence is up to 12% when the surface-trap emission was totally eliminated after a gentle oxidation under laboratory fluorescent light.

Journal Article↗
PubMed2004

Synthesis of square gadolinium-oxide nanoplates.

In this paper, we report a colloidal synthesis of high-quality, square, plate-shaped Gd2O3 nanocrystals. These nanoplates are single crystalline with a thickness of the Gd2O3 unit-cell edge length, approaching the lower limit of crystal growth.

Journal Article↗
PubMed2003

Raman dye-labeled nanoparticle probes for proteins.

In this paper, we demonstrate how one can chemically design Raman dye-functionalized nanoparticle probes with specific protein-binding affinities and use these probes, coupled with surface-enhanced Raman scattering (SERS) spectroscopy, to perform multiplexed screening of protein-small molecule interactions and protein-protein interactions in a protein microarray format.

2,4-Dinitrophenol↗
PubMed2003

Controlling anisotropic nanoparticle growth through plasmon excitation.

Inorganic nanoparticles exhibit size-dependent properties that are of interest for applications ranging from biosensing and catalysis to optics and data storage. They are readily available in a wide variety of discrete compositions and sizes. Shape-selective synthesis strategies now also yield shapes other than nanospheres, such as anisotropic metal nanostructures with interesting optical properties. Here we demonstrate that the previously described photoinduced method for converting silver nanospheres into triangular silver nanocrystals--so-called nanoprisms--can be extended to synthesize relatively monodisperse nanoprisms with desired edge lengths in the 30-120 nm range. The particle growth process is controlled using dual-beam illumination of the nanoparticles, and appears to be driven by surface plasmon excitations. We find that, depending on the illumination wavelengths chosen, the plasmon excitations lead either to fusion of nanoprisms in an edge-selective manner or to the growth of the nanoprisms until they reach their light-controlled final size.

Journal Article↗