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Highly luminescent SiO2beads with concentrated CdTe quantum-dots (QDs) stabilized by thioglycolic acid (TGA) have been prepared by using a two-step synthesis including coating the surface of the QDs with SiO2and subjecting them to a subsequent inverse micelle process. Two types of bead structures were formed together with a solid structure, depending on the preparation procedures and conditions. The first contains a composite consisting of Cd2+, TGA, SiO2, and QDs (with egg-yolk structure). This composite was created when highly alkaline water (pH ≥10) was added to the solution of surface-coated QDs before a sol–gel reaction occurred in the water droplets though the migration of the content inside the droplets before they solidified. The second contains a void inside of them (hollow structure). This void was formed when highly alkaline water was added after the water droplets had formed. The beads thus prepared demonstrated high photoluminescence efficiency (70%, almost same as the initial colloidal solution) that was maintained for more than a week in water. The lifetime measurement indicates the reduction of non-radiative rate and increment of radiation lifetime of QDs by the SiO2coating. The mean concentration of QDs in typical beads was about 0.002 M, where ca.140 QDs were dispersed in all SiO2beads 60 nm in diameter. [ABSTRACT FROM AUTHOR]

Studies large third-order optical nonlinearities in transition-metal oxides. Electronic absorption spectra of third-order transition-metal oxide films; Optical properties of several third-order nonlinear optical materials; Relationship between the third-order nonlinear optical susceptibility and the absorption coefficient of oxide films.

Monodisperse InP nanocrystals were prepared by a facile one-pot solvothermal route via the pyrolysis reaction between indium chloride and tris(dimethylamino)phosphine at relatively low temperatures (150-180 °C). The InP nanocrystals after size-selective precipitation had a well-crystallized zinc blende structure, a narrow size distribution, and distinguishable absorption peaks. Application of HF treatment in combination with photoetching increased their emission efficiency to 58% while their emission wavelengths were tunable from green to red. [ABSTRACT FROM AUTHOR]

An abstract of the article "Aqueous Preparation of Highly Luminescent CdSe/ZnS Nanocrystals through Photochemical Processing," by Chunliang Li and colleagues is presented.