The ability to control chemical and physical structuring at the nanometre scale is important for developing high-performance thermoelectric materials. Progress in this area has been achieved mainly by enhancing phonon scattering and consequently decreasing the thermal conductivity of the lattice through the design of either interface structures at nanometre or mesoscopic length scales or multiscale hierarchical architectures. A nanostructuring approach that enables electron transport as well as phonon transport to be manipulated could potentially lead to further enhancements in thermoelectric performance. Here we show that by embedding nanoparticles of a soft magnetic material in a thermoelectric matrix we achieve dual control of phonon- and electron-transport properties. The properties of the nanoparticles-in particular, their superparamagnetic behaviour (in which the nanoparticles can be magnetized similarly to a paramagnet under an external magnetic field)-lead to three kinds of thermoelectromagnetic effect: charge transfer from the magnetic inclusions to the matrix; multiple scattering of electrons by superparamagnetic fluctuations; and enhanced phonon scattering as a result of both the magnetic fluctuations and the nanostructures themselves. We show that together these effects can effectively manipulate electron and phonon transport at nanometre and mesoscopic length scales and thereby improve the thermoelectric performance of the resulting nanocomposites.

A straightforward and effective polyol route for the controllable synthesis of high-quality gold (Au) octahedra with uniform size is presented in an ethylene glycol solution. Large-scale Au octahedra with the size ranging from tens to hundreds of nanometers were selectively synthesized in high-yield. The surfaces of octahedral Au nanocrystals are smooth and correspond to {111} planes. Formation of Au nanooctahedra was attributed to the preferential adsorption of cationic surfactant poly(diallyldimethylammonium) chloride (PDDA) molecules on the {111} planes of Au nuclei that inhibited the growth rate along the <111> direction. The reduction rate of gold ions in the synthesis process can be rationally manipulated by acidic and basic solutions. This provides a facile and effective route to harvest Au octahedra with different dimensions. The synthetic strategy has the advantage of one-pot and requires no seeds, no foreign metal ions, and no pretreatment of the precursor, so that this is a practical method for controllable synthesis of Au octahedra. Size-dependent optical properties of Au octahedra were numerically and experimentally analyzed. The analysis shows that Au octahedra with sharp edges possess attractive optical properties, promising their applications to surface-enhancement spectroscopy, chemical or biological sensing, and the fabrication of nanodevices.

We apply a nanomanipulation technique to assemble pairs of monodispersed octahedral gold nanocrystals (side length, 150 nm) along their major axes with a varying tip-to-tip separation (25-125 nm). These pairs are immobilized onto indium tin oxide coated silica substrates and studied as plasmonic dimers by polarization-selective total internal reflection (TIR) microscopy and spectroscopy. We confirm that the plasmon coupling modes with the scattering polarization along the incident light direction result from the transverse-magnetic-polarized incident light, which induces two near-field-coupled dipole moments oriented normal to the air-substrate interface. In such cases, both in-phase (antibonding) and antiphase (bonding) plasmon coupling modes can be directly observed with the incident light wave vector perpendicular and parallel to the dimer axis, respectively. The observation of antiphase plasmon coupling modes ("dark" plasmons) is made possible by the unique polarization nature of the TIR-generated evanescent field. Furthermore, with decreasing nanocrystal separation, the plasmon coupling modes shift to shorter wavelengths for the incident light perpendicular to the dimer axis, whereas relatively large red shifts of the plasmonic coupling modes are found for the parallel incident light.

A facile approach for the fabrication of novel black plasmonic colloidosomes assembled from Au nanospheres is developed by an emulsion-templating strategy. This self-assembly process is based on a new reverse water-in-1-butanol emulsion system, in which the water emulsion droplets can dissolve into 1-butanol (oil) phase at an appropriate rate. These Au colloidosomes possess hexagonal close-packed multilayer shells and show a low reflectivity and intense broadband absorption owing to the strong interparticle plasmonic coupling, which is further investigated by a finite-difference time-domain method. This method is universal and is suitable for self-assembly of different noble-metal nanoparticles into different colloidosomes. These colloidosomes have important applications in photothermal therapy, biosensors, and drug delivery.

Superparamagnetic Fe3O4 nanoparticles remarkably enhance the room-temperature thermoelectric and cooling performance of BiSbTe alloys.

Pieces of eight: Single‐crystalline Au nano‐octahedra with well‐defined shape and tunable size can be synthesized by a modified polyol process. The octahedral Au nanocrystals have sharp corners and display optical properties that are sensitive to the crystal sizes and the truncation of the tips.

We present a facile synthetic route to a silver bowl-like array film with hierarchical structures on glass substrate using the colloidal monolayer as a template. In these special hierarchical structures, microstructures were provided by a colloidal template of polystyrene latex spheres and nanostructures resulting from the thermal decomposition of silver acetate. These structures were chemically modified with 1-hexadecanethiol, and a corresponding self-assembled monolayer (SAM) was formed on their surfaces. Due to the lotus leaf-like morphology with hierarchical micro/nanostructures, the film displayed an extraordinary superhydrophobicity after chemical modification. Water contact angle and sliding angle were 169 degrees and 3 degrees (the weight of water droplets: 3 mg), respectively. Additionally, its optical property has also been investigated. This structure could be used in microfluidic devices, optical devices, and biological science.

Au/Pd bimetallic nanoparticles, even with core-shell structure, were synthesized by successive and simultaneous sonochemical irradiation of their metal precursors in ethylene glycol, respectively. In the successive method, Pd clusters or nanoparticles are first obtained by reduction of Pd(NO 3) 2 , followed by adding HAuCl 4 solution. As a result, Au-core/Pd-shell structured particles are formed, instead of Pd-core/Au-shell as usually expected. The successive method is more effective than the simultaneous one in the formation of the core-shell structure. Detailed investigation with optical absorption spectroscopy suggested that the pre-formed Pd atoms or clusters have a reduction effect on Au 3+ ions and the post-formation of Pd-shell can damp the surface plasmon resonance of Au nanoparticles. Theoretical absorption spectra based on Mie-like model for core-shell structured particles yield excellent agreement with the experimental results.