Mg nanocrystals of controllable sizes were prepared in gram quantities by chemical reduction of magnesocene using a reducing solution of potassium with an aromatic hydrocarbon (either biphenyl, phenanthrene, or naphthalene). The hydrogen sorption kinetics were shown to be dramatically faster for nanocrystals with smaller diameters, although the activation energies calculated for hydrogen absorption (115-122 kJ/mol) and desorption (126-160 kJ/mol) were within previously measured values for bulk Mg. This large rate enhancement cannot be explained by the decrease in particle size alone but is likely due to an increase in the defect density present in smaller nanocrystals.

We present data for batch-to-batch variation of silver nanoparticles (AgNPs) synthesized with orange peel extract. These samples were prepared in the CEM microwave for 15 min. The relative standard deviation (as a measure of precision) is provided and is, in most cases, less than 20%.

Cu₂ZnSnS₄ (CZTS) nanocrystals, synthesized by a hot injection solution method, have been fabricated into thin films by dip-casting onto fluorine doped tin oxide (FTO) substrates. The photoresponse of the CZTS nanocrystal films was evaluated using absorbance measurements along with photoelectrochemical methods in aqueous electrolytes. Photoelectrochemical characterization revealed a p-type photoresponse when the films were illuminated in an aqueous Eu(3+) redox electrolyte. The effects of CZTS stoichiometry, film thickness, and low-temperature annealing on the photocurrents from front and back illumination suggest that the minority carrier diffusion and recombination at the back contact (via reaction of photogenerated holes with Eu(2+) produced from photoreduction by minority carriers) are the main loss mechanisms in the cell. Low-temperature annealing resulted in significant increases in the photocurrents for films made from both Zn-rich and stoichiometric CZTS nanocrystals.

A thorough structure determination has been performed on Cu 2 ZnSnS 4 nanoparticles, a popular photovoltaic material, using neutron diffractionto characterize the long-range average crystal structureand X-ray absorption fine structure (XAFS) spectroscopy at the Cu, Zn, and Sn K-edges to elucidate the element-specific local structure. This is the first combined multiscale approach on nanoparticles of this material. The results indicate the presence of aperiodic disorder on the cation sites that is diminished by annealing. This disorder involves local lattice distortions around the crystallographic sites rather than the presence of interstitial atoms. It is most consistent with the known antisite substitutions that are integral to CZTS (referring to the ordering of the Cu, Zn, and Sn between planes). However, instead of being confined within single unit cells so as to maintain the crystallographic symmetry, periodicity, and homogeneity, the substitutional disorder appears to extend over larger regions consisting of multiple unit cells but still smaller than the physical dimensions of the nanoparticles. These results therefore imply the presence of nanoscale domains characterized by local fluctuations in composition that cause the individual domains to be enriched in certain metal ions and depleted in others. These will be mirrored by domains with the opposite fluctuations at other locations in the crystal so that the overall composition remains close to the stoichiometric Cu 2 ZnSnS 4 . This disorder is likely pronounced in these samples due to the relatively low temperature reaction (300 °C) and annealing (350 °C) conditions and can be expected to have a significant effect on the resulting physical properties of the material and its photovoltaic performance.