Solution Phase Growth and Ion Exchange in Microassemblies of Lead Chalcogenide Nanoparticles.

We demonstrate the synthesis of micron-sized assemblies of lead chalcogenide nanoparticles with controlled morphology, crystallinity, and composition through a facile room-temperature solution phase reaction. The amine-thiol solvent system enables this synthesis with a unique oriented attachment growth mechanism of nanoparticles occurring on the time scale of the reaction itself, forming single-crystalline microcubes of PbS, PbSe, and PbTe materials. Increasing the rate of reaction by changing reaction parameters further allows disturbing the oriented attachment mechanism, which results in polycrystalline microassemblies with uniform spherical morphologies.

Speciation of CuCl and CuCl Thiol-Amine Solutions and Characterization of Resulting Films: Implications for Semiconductor Device Fabrication.

Thiol-amine mixtures are an attractive medium for the solution processing of semiconducting thin films because of their remarkable ability to dissolve a variety of metals, metal chalcogenides, metal salts, and chalcogens. However, very little is known about their dissolution chemistry. Electrospray ionization high-resolution tandem mass spectrometry and X-ray absorption spectroscopy were employed to identify the species formed upon dissolution of CuCl and CuCl in 1-propanethiol and n-butylamine.

Directing solar photons to sustainably meet food, energy, and water needs.

As we approach a "Full Earth" of over ten billion people within the next century, unprecedented demands will be placed on food, energy and water (FEW) supplies. The grand challenge before us is to sustainably meet humanity's FEW needs using scarcer resources. To overcome this challenge, we propose the utilization of the entire solar spectrum by redirecting solar photons to maximize FEW production from a given land area.