In this study, we demonstrate that Cu 2 ZnSn(S x Se 1Àx ) 4 nanocrystals with a tunable bandgap could be synthesized by a ''hot-injection'' protocol. In this protocol, metal stearates dissolved in oleylamine were injected into a hot solution of anion precursors in 1-octadecene (ODE) at a given reaction temperature. ODE, which is a low-cost, low-hazard, and air-stable liquid, was used as the solvent. Oleylamine was chosen as both the reagent to activate the precursors and as the capping agent for the nanocrystals. The composition of the Cu 2 ZnSn(S x Se 1Àx ) 4 nanocrystals could be adjusted across the x range from 0 to 1 by varying the S/Se reactant ratio. The lattice parameters (a and c) measured from X-ray diffraction patterns decreased linearly with increasing Se content. This trend was consistent with Vegard's law, which confirmed the formation of homogeneous Cu 2 ZnSn(S x Se 1Àx ) 4 nanocrystals. The A 1 symmetry modes of the Cu 2 ZnSn(S x Se 1Àx ) 4 nanocrystals seen by Raman spectroscopy gradually shifted with decreasing x (S content) to the lower frequency side and completely disappeared when x ¼ 0. The absorption spectra of the Cu 2 ZnSn(S x Se 1Àx ) 4 nanocrystals revealed that the bandgaps of the nanocrystals could be adjusted over the range 1.0-1.5 eV by decreasing the S content. The relatively small value for the bowing parameter indicated that the synthesized Cu 2 ZnSn(S x Se 1Àx ) 4 nanocrystals had good miscibility.

Diamond-like carbon (DLC) nanocomposite films were deposited at room temperature by inductively coupled plasma chemical vapor deposition using hexamethyldisilane (HMDS), hexamethyldisilazane (HMDSN), and hexamethyldisiloxane (HMDSO) precursors. High-resolution transmission electron microscopy showed that all the films contained nanoparticles. The DLC nanocomposite films deposited by HMDS contained hollow spherical nanocrystallites, called nanoballs, of hexagonal silicon carbide. The nanocomposite films deposited by HMDSN contained crystalline Si3N4 nanoparticles. The nanocomposite films deposited by HMDSO contained amorphous SiOx nanoparticles. Although both types of films had similar hardness, the DLC nanocomposite films exhibited much lower compressive stresses than the DLC films deposited by methane, i.e., 1.5 vs 11 GPa, respectively. Through the enhancement of gas phase reactions, the inductively coupled plasma should be responsible for the formation of nanoparticles in the nanocomposite films.

Interesting properties of water with distinguishable hydrogen-bonding structure on interfacial phase or in confined environment have drawn wide attentions. However, these unique properties of water are only found within the interfacial phase and confined environment, thus, their applications are limited. In addition, quantitative evaluation on these unique properties associating with the enhancement of water's physical and chemical activities represents a notable challenge. Here we report a practicable production of free-standing liquid water at room temperature with weak hydrogen-bonded structure naming Au nanoparticles (NPs)-treated (AuNT) water via treating by plasmon-induced hot electron transfer occurred on resonantly illuminated gold NPs (AuNPs). Compared to well-known untreated bulk water (deionized water), the prepared AuNT water exhibits many distinct activities in generally physical and chemical reactions, such as high solubilities to NaCl and O2. Also, reducing interaction energy within water molecules provides lower overpotential and higher efficiency in electrolytic hydrogen production. In addition, these enhanced catalytic activities of AuNT water are tunable by mixing with deionized water. Also, most of these tunable activities are linearly proportional to its degree of nonhydrogen-bonded structure (DNHBS), which is derived from the O-H stretching in deconvoluted Raman spectrum.

Controlling and understanding the surface migration of Au atoms are useful in tailoring the length, shape, and structure of nanowires for future applications.' ASSOCIATED CONTENT b S Supporting Information. TEM images of the Au-Ga seeds diffusing along a GaN nanowire surface as the nanowire was grown under intermediate gallium partial pressure after a growth period of 20 min; EDS results of Au-Ga seeds and GaN nanowires in Figure 3 of the manuscript; and a schematic illustration of a Au-assisted VLS (or VSS) mechanism for the growth of GaN nanowires. This material is available free of charge via the Internet at http://pubs.acs.org.

Surface-enhanced Raman scattering (SERS) utilizing the well-defined localized surface plasmon resonance (LSPR) of Ag and Au nanoparticles (NPs) under resonant irradiation has emerged as a promising spectroscopy technique for providing vibrational information on trace molecules. The Raman scattering intensity from molecules close to the surface of these finely divided metals can be significantly enhanced by a factor of more than 10(6). In addition to the high sensitivity, the reproducibility of the SERS signal is also an important parameter for its reliable application. In this work, we report on the innovative and facile fabrication of a Au NP-decorated SiO2 mask coated on indium tin oxide (ITO) glass as a SERS array substrate. First, a highly ordered porous SiO2 mask with pore sizes of 350 nm in diameter and wall thickness of 60 nm was deposited on ITO glass by using spin coating. Then, Au NPs were controllably decorated into the pores of the conductive ITO glass-bottomed SiO2 mask by using sonoelectrochemical deposition-dissolution cycling (SEDDC). Experimental results indicate that the SERS effect of Rhodamine 6G (R6G) observed on this developed substrate increases with an increase in the deposition time of Au NPs in SEDDC. The corresponding optimal enhancement factor (EF) that is obtained is ca. 6.5 × 10(7). Significantly, this system achieves an optimal reproducibility under a medium-length deposition time of Au NPs in SEDDC with a relative standard deviation (RSD) of 12% for measurements of five spots on different areas. The low RSD of the SERS signal and the large EF suggest that the developed array system can serve as an excellent spectroscopy platform for practical applications in analytical chemistry.