With octahedral Au nanocrystals as seeds, highly monodisperse Au@Pd and Au@Ag core-shell nanocubes were synthesized by a two-step seed-mediated method in aqueous solution. Accordingly, we have preliminarily proposed a general rule that the atomic radius, bond dissociation energy, and electronegativity of the core and shell metals play key roles in determining the conformal epitaxial layered growth mode.

Plasmonic metal/semiconductor heterostructures show promise for visible-light-driven photocatalysis. Gold nanorods (AuNRs) semi-coated with TiO2 are expected to be ideally structured systems for hydrogen evolution. Synthesizing such structures by wet-chemistry methods, however, has proved challenging. Here we report the bottom-up synthesis of AuNR/TiO2 nanodumbbells (NDs) with spatially separated Au/TiO2 regions, whose structures are governed by the NRs' diameter, and the higher curvature and lower density of CnTAB surfactant at the NRs' tips than on their lateral surfaces, as well as the morphology's dependence on concentration, and alkyl chain length of CnTAB. The NDs show plasmon-enhanced H2 evolution under visible and near-infrared light.

Polymeric electronic materials have enabled soft and stretchable electronics. However, the lack of a universal micro/nanofabrication method for skin-like and elastic circuits results in low device density and limited parallel signal recording and processing ability relative to silicon-based devices. We present a monolithic optical microlithographic process that directly micropatterns a set of elastic electronic materials by sequential ultraviolet light–triggered solubility modulation. We fabricated transistors with channel lengths of 2 micrometers at a density of 42,000 transistors per square centimeter. We fabricated elastic circuits including an XOR gate and a half adder, both of which are essential components for an arithmetic logic unit. Our process offers a route to realize wafer-level fabrication of complex, high-density, and multilayered elastic circuits with performance rivaling that of their rigid counterparts.

Deduced from thermodynamics and the Thomson-Gibbs equation that the surface energy of crystal face is in proportion to the supersaturation of crystal growth units during the crystal growth, we propose that the exposed crystal faces can be simply tuned by controlling the supersaturation, and higher supersaturation will result in the formation of crystallites with higher surface-energy faces. We have successfully applied it for the growth of ionic (NaCl), molecular (TBPe), and metallic (Au, Pd) micro/nanocrystals with high-surface-energy faces. The above proposed strategy can be rationally designed to synthesize micro/nanocrystals with specific crystal faces and functionality toward specific applications.

We demonstrate a new approach for synthesizing Ag-ZnO heterogeneous nanostructures in which single-crystalline ZnO nanorods were selectively grown on {111} rather than {100} facets of single-crystalline Ag truncated nanocubes. We have identified the fine structure of the Ag-ZnO heterostructures and proposed a mechanism indicating that structure match plays a critically important role in this type of facet-selective growth. These heterogeneous nanostructures are of special interest and have potential applications in electrical contacts, functional devices, biological sensors, and catalysis.