Multichromophoric dendrimers are increasingly being considered for solar energy systems. To design materials with suitably efficient photon collection demands a thorough understanding of crucial photophysical conditions and electrodynamic mechanisms, many of which prove to emulate photosynthetic systems. Key parameters include the chromophore absorption properties, the generation, branching and folding of the dendrimer, and the presence of a spectroscopic gradient. Driving excitation towards a trap, resonance energy transfer favors migration between nearest neighbor chromophores. In modeling the progress of excitation from antenna chromophores towards the trap, a propensity matrix method has broad applicability, giving physical insights of generic validity. Calculations on specific dendrimers are best served by quantum chemistry models; again, links with photobiological systems can be discerned. Two important optically nonlinear features are cooperative energy pooling, and two-photon energy transfer. Branch multiplicity and the polar or polarizable nature of the chromophores also play important roles in determining energy harvesting characteristics.

Recently, tremendous progress has been made toward the application of organic light-emitting diodes (OLEDs) in full color flat panel displays and other devices. This article reviews and discusses our recent progress in extended development of emissive semi-interpenetrating polymer networks (E-semi-IPNs) and hybrid quantum dots (QDs)–polymer nanocomposites for use in multicolor and multilayer OLED pixels through low-cost solution processing. Our semi-IPNs with high solvent resistance, containing an inert polymer network and conjugated polymers, served in different layers of OLED devices. These semi-IPNs do not require complicated chemical modification to OLED materials; therefore, many state-of-the-arts conjugated polymers can be utilized to achieve red–green–blue and white OLEDs by tuning formulations. Our research findings on hybrid QD–oligomer nanocomposites lead to the successful design and synthesis of QD–polymer hybrid nanocomposites, which were used to build proof-of-the-concept devices showing good promise in providing excellent color purity and stability from QDs and solution processability from hybrid nanocomposites.

Electrophoretic displays (EPDs) are attracting a great deal of academic and commercial interest due to the advantages of both electronic displays and conventional paper. The key materials for EPD application of microcapsules are the electrophoretic particles and the capsule wall enwrapping the electrophoretic suspension inside. Here, black and white electrophoretic particles with low density and good dispersity such as titanium dioxide, carbon black, and Cu2Cr2O3 were prepared by surface modification of the pigments. The preparation and properties of the gelatin-based microcapsules prepared by complex coacervation methods are also summarized. The microcapsules have transparent and elastic walls of compact structure, which endows them with good barrier properties and thermal stability for EPD application. EPD prototype devices based on the obtained microcapsules were prepared and could be driven at 9 V.

Although atomic layer deposition (ALD) has been used for many years as an industrial manufacturing method for microprocessors and displays, this versatile technique is finding increased use in the emerging fields of plasmonics and nanobiotechnology. In particular, ALD coatings can modify metallic surfaces to tune their optical and plasmonic properties, to protect them against unwanted oxidation and contamination, or to create biocompatible surfaces. Furthermore, ALD is unique among thin film deposition techniques in its ability to meet the processing demands for engineering nanoplasmonic devices, offering conformal deposition of dense and ultrathin films on high-aspect-ratio nanostructures at temperatures below 100 °C. In this review, we present key features of ALD and describe how it could benefit future applications in plasmonics, nanosciences, and biotechnology.

Depending on the application of nanoparticles, certain characteristics of the product quality such as size, morphology, abrasion resistance, specific surface, and tendency to agglomeration are important. These characteristics are a function of the physicochemical properties of the nanostructured material and, thus, of the process parameters of the particle synthesis. Because of econimical reasons in large-scale production such as pyrolysis or precipitation processes, nanosized particles are produced not as single primary particles but rather as aggregates or agglomerates. The application properties of these aggregates are strongly affected by the micromechanical properties, which can be measured via nanoindentation. In this study, a flat punch method was used. For the measurements, model aggregates out of sol–gel produced silica with varying primary particle size and strength of solid bonds were used. Generally, the micromechanical properties can be characterized by measuring the micromechanical properties via nanoindentation and be described by different theoretical models.

Thin native oxide layers can dominate the mechanical properties of metallic thin films. However, to date there has been little quantification of how such overlayers affect yield and fracture during indentation in constrained film systems. To gain insight into such processes, electrical contact resistance was measured in situ during nanoindentation on constrained thin films of epitaxial Cr and polycrystalline Al, both possessing a native oxide overlayer. Measurements during loading of the films show both increases and decreases in current, which can then be used to distinguish between various sources of plasticity. Ex situ measurements of the oxide thickness are used to provide a starting point for elasticity simulations of stress in both systems. The results show that dislocation nucleation in the metal film can be differentiated from oxide fracture during indentation.

A combined dislocation–cohesive zone model was proposed to describe the fracture toughness of nanocrystalline (nc) materials. In the framework of the model, cohesive stress near crack tip initiates edge dislocations, which move to the opposite grain boundaries. The emitted dislocations provide a shielding effect of the crack. The dependence of both the maximum number of dislocations, emitted by a crack, and the critical stress intensity factor on grain size d (ranging from 20 to100 nm) for Cu was calculated. The calculated results show that (i) nc materials have low fracture toughness, (ii) the critical stress intensity factor decreases with decreased grain size, and (iii) the grain size effect is not high; for instance, increasing the grain size from 20 to 100 nm increases the value of critical stress intensity factor only by 0.035 MPa/m1/2.

The Zr65Al7.5Ni10Cu17.5 bulk metallic glasses were prepared by injection casting (casting temperature of 1100 °C) and in situ suction casting (casting temperature as high as 3000 °C). The strain-rate-dependent mechanical behaviors of the specimens were investigated under axial compression at room temperature over a wide strain rate range (1.6 × 10−5–1.6 × 10−1 s−1). The specimens prepared by injection casting exhibited negative strain rate sensitivity, i.e., the yield stress decreased with increasing strain rate. In contrast, no strain rate sensitivity was observed for the specimens prepared by in situ suction casting. The different strain rate sensitivities in the specimens prepared at different temperatures were probably caused by the diversities of the local atomic structures.

Chips produced by turning a commercial purity magnesium billet were cold compacted and then hot extruded at four different temperatures: 250, 300, 350, and 400 °C. Cast billets, of identical composition, were also extruded as reference material. Chip boundaries, visible even after 49:1 extrusion at 400 °C, were observed to suppress grain coarsening. Although 250 °C extruded chip-consolidated product showed early onset of yielding and lower ductility, fully dense material (extruded at 400 °C) had nearly 40% reduction in grain size with 22% higher yield strength and comparable ductility as that of the reference. The study highlights the role of densification and grain refinement on the compression behavior of chip consolidated specimens.

The asymmetrical hysteresis loops of the longitudinal field annealed Co58Fe5Ni10Si11B16 amorphous ribbons were studied. Longitudinal magnetic training was deliberately performed on the annealed samples with exchange bias behavior. It was found that the shifted loops can be technically controlled by training the ribbons to modulate the abnormal magnetic features. The scanning probe microscope results reveal that the AC longitudinal magnetic training can decrease the vertical magnetic signal on the sample surface to a great extent. This skillful magnetic training method provides an approach to tailor the exchange bias behavior in the Co-based amorphous ribbons for potential applications.

The Fe64B22.8Nd6.6Y3.9Nb2.7 nanocomposite permanent magnets in the form of rods of 2 mm in diameter and 25 mm in length have been prepared by annealing the amorphous precursors. The phase evolution, microstructure, and magnetic properties of Fe64B22.8Nd6.6Y3.9Nb2.7 nanocomposite permanent magnets have been investigated by x-ray diffractometry, transmission electron microscopy, and magnetometry techniques. The exchange coupling between the magnetically soft and hard magnetic phase is evidenced by the δM curves. The hard magnetic properties of the nanocomposites were found to be sensitive to the annealing process. The microstructure of the annealed nanocomposite consists of magnetically soft α-Fe (15–25 nm) and Fe3B (25–35 nm) grains and hard magnetic Nd2Fe14B (45–55 nm) grains. The optimum hard magnetic properties, such as jHc = 961.6 kA/m (12.0 kOe), Br = 0.65 T (6.5 kG), and BHmax = 65.17 kJ/m3 (8.19 MGOe), were obtained by annealing the alloy at 700 °C for 15 min and are related to the more refined nanostructure leading to strong exchange coupling between the soft and hard magnetic grains. Annealing above 700 °C induces a decoupling effect due to the coarsening of soft and hard magnetic phases.

Two kinds of type-II heterostructures (HSs) of ZnO (wurtzite)/ZnSe (wurtzite) [ZnO (WZ)/ZnSe (WZ)] and ZnO (wurtzite)/ZnSe (zinc blende) [ZnO (WZ)/ZnSe (ZB)] were designed for photovoltaic applications by first-principle calculations. The calculated effective bandgap of 1.51 eV for the ZnO (WZ)/ZnSe (WZ) HS is more favorable for solar cell applications compared to that of 1.69 eV for the ZnO (WZ)/ZnSe (ZB) HS. Furthermore, the electrons and holes are more effectively separated at the interface of ZnO (WZ)/ZnSe (WZ) HS due to the stronger misfit stress field. Finally, a strained ZB ZnSe layer was introduced to transport the separated holes from WZ ZnSe layer, and an optimal structure of ZnO (WZ)/ZnSe (WZ)/ZnSe (ZB) was proposed to realize a solar cell with near-infrared response.

In this article, the binary-phased PbTe–Sb2Te3 nanopowders were synthesized via a hydro/solvo-thermal route to improve the thermoelectric properties of PbTe matrix material. The single-phased PbTe powders exhibit pure nanoparticles, but the binary-phased PbTe–Sb2Te3 powders have a mixed morphology composed of nanospheres and nanoribbons. Our results suggest that the thermal conductivity of the binary-phased PbTe–Sb2Te3 bulks can be reduced significantly and the Seebeck coefficient can be increased obviously, although the electrical conductivity can also be decreased sharply. Consequently, a large figure of merit 0.85 at 623 K can be achieved for 0.7PbTe–0.3Sb2Te3 bulk, which is enhanced by about one time as compared to that of the single-phased PbTe bulk. This large enhancement could be attributed to the lowered carrier concentration and the increased interface scattering in the binary-phased PbTe–Sb2Te3 materials with a mixed morphology.