We report a rational method for preparation of ternary alloy (PtNiFe) nanocrystals with various shapes. PtNiFe nanocubes, polyhedrons, and octahedrons are prepared via fine-tuning the alloy compositions and surfactants, so that the crystal facet−surfactant bindings on the growth seed can be well controlled. Nanowires grow in the cylindrical template built via high concentrations of oleylamine. In the electrocatalysis examination, it appears that the oxygen reduction reaction (ORR) activities of all PtNiFe nanostructures outperform that of commercial Pt catalyst in the electrolyte of HClO 4 or H 2 SO 4 . In HClO 4 , the order of ORR activity is as follows: octahedrons ≈ nanowires > polyhedrons > nanocubes. PtNiFe nanostructures enclosed by a (111) plane, such as octahedrons and nanowires, give the highest ORR activities. Conversely, in H 2 SO 4 , the ORR activity of PtNiFe nanocubes enclosed by {100} facets is the highest among these nanostructures. The ORR activity increases in the order of nanowires ≈ octahedrons < polyhedrons, establishing a shape dependency in the ORR activity, which is valuable upon performing nanocatalysis in fuel cells.

Despite a variety of T1–T2 dual-modal contrast agents (DMCAs) reported for magnetic resonance imaging (MRI), no tuning of local induced magnetic field strength of an DMCA, which is important to modulate the overall T1 and T2 responses for imaging delicate cells, tissues, and organs, is yet available. Here, we show that a spatial arrangement of T1 and T2 components within a “nano zone” in a single core–shell nanoparticle carrier (i.e., DMCA with core Fe3O4 and MnO clusters in a silica shell) to produce the necessary fine-tuning effect. It is demonstrated that this particle after the anti-CD133 antibody immobilization allows both T1 and T2 imaging at higher resolution for living ependynmal brain cells of rodents with no local damage under a strong MRI magnetic field. This study opens a route to rational engineering of DMCAs for accurate magnetic manipulations in a safe manner.

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In the work, mechanisms behind various 3D-nanocrystals enhanced performance of bulk heterojunction solar cells were studied comprehensively. Four types of gold nanoparticles (NPs) with distinctly different shapes and great uniformity were designed and synthesized, including cubes, rhombic dodecahedra (RD), edge-and corner-truncated octahedra (ECTO), and triangular plates, to systematically probe their influences on photovoltaic. RD and triangular plates show a higher growth rate, while slower growth favors cubes and ECTO formation by controlling reduction agent and capping ions amount. NPs with increasing corners and proper size of crosssection induce stronger near-field coupling and far-field scattering in P3HT:PC 61 BM based active layers. Both finite-difference time-domain simulation and UV-visible absorption spectra firmly support that RD exhibit the strongest localized surface plasmon resonance and optical scattering. With optimized condition, a high power conversion efficiency exceeding 4% was reproducibly achieved.

Tagging recognition group(s) on superparamagnetic iron oxide is known to aid localization (imaging), stimulation and separation of biological entities using magnetic resonance imaging (MRI) and magnetic agitation/separation (MAS) techniques. Despite the wide applicability of iron oxide nanoparticle in T2-weighted MRI and MAS, the quality of image and safe manipulation of exceptionally delicate neural cells in a live brain are currently the key challenges. Here, we demonstrate the engineered manganese oxide clusters-iron oxide core-shell nanoparticle as a MR dual-modal contrast agent (DMCA) for the applications in neural stem cells imaging and magnetic manipulation in live rodent. As a result, using this engineered nanoparticle and associated technologies, identification, stimulation and transportation of labelled potentially multipotent neural stem cells from a specific location of a live brain to another by magnetic means for self-healing therapy can therefore be made possible.