Solution-processed hole contact layers (HCLs) of metal oxide nanoparticle (NP) films improve performance of organic photovoltaics (OPVs), but have thus far required harsh post-deposition thermal or plasma treatments. Here, we describe a general method to synthesize suspensions of ultrasmall (1–2 nm) MoO3, WO3, NiOx, and CoOx NPs in n-butanol. Spin-coated metal oxide NP films with no post-deposition treatment exhibit high work function and ionization energy consistent with the oxidation states of the metal cations. Metal oxide NP HCLs demonstrate performance matching those of reference conventional and inverted OPVs containing PEDOT:PSS and evaporated MoO3.

First principles density functional theory calculations were conducted to investigate the structures and energetics of polyhedral oligomeric silsesquioxane (POSS) molecules with varying aluminum and alkali (sodium or potassium) concentrations. Notable trends emerge from this study namely, (1) the thermodynamic stability of the substituted POSS molecules is critically dependent on the interplay between size and composition of the POSS structures, and (2) larger POSS structures provide lower central electron density and hence better accommodate the central alkali atom. These observations, when viewed in the context of aluminosilicate based geopolymers, provide fundamental insights into the relations that describe the structure composition interplay of their underlying monomers.

Heterogeneous magnesium matrix nanocomposites (Hetero-Mg-NCs) exhibited excellent strength–toughness synergy, but their damage behavior and toughness mechanism lacked of investigation. Here, atomic force microscopy was first employed to characterize the microstructure evolution and damage behavior of the Hetero-Mg-NCs after indentation. The heterogeneous structure comprised of pure Mg areas (soft phase) and Mg nanocomposite areas (hard phase) was revealed by the electrostatic force microscopy. Furthermore, the surface morphology and cracks of the deformed area were investigated with high resolution. The results indicated the soft phase undertook most of the deformation and played an important role in capturing and blunting the crack.

We report on the low-temperature electrical characterization of bilayer MoS2 treated with increasing dose of oxygen:argon (1:3) plasma. We characterize the effective Schottky barrier heights as a function of plasma exposure time and observe a significant barrier lowering, with no accompanying p-type conduction in the negative bias region. Furthermore, we observe a crossover in the temperature-dependent conduction regimes below 181 K due to the plasma exposure. The Efros–Shklovskii (ES) hopping regime is seen to transform upon plasma exposure to a mixed ES/thermally-activated regime at high temperatures, and to a strongly short-range Arrhenius regime at low temperatures. We attribute the observed crossovers to a critical defect density created by the surface reaction with the plasma.

Silver nanowire-based contacts represent one of the major new directions in transparent contacts for opto-electronic devices with the added advantage that they can have Indium-Tin-Oxide-like properties at substantially reduced processing temperatures and without the use of vacuum-based processing. However, nanowires alone often do not adhere well to the substrate or other film interfaces; even after a relatively high-temperature anneal and unencapsulated nanowires show environmental degradation at high temperature and humidity. Here we report on the development of ZnO/Ag-nanowire composites that have sheet resistance below 10 Ω/sq and >90% transmittance from a solution-based process with process temperatures below 200 °C. These films have significant applications potential in photovoltaics and displays.

A model is developed and implemented for load-controlled instrumented conical indentation of a brittle open-cell foam on a dense substrate. A survey of observations suggests that such indentations are typified by displacement excursions at small indentation loads, load-displacement variability, localized crushing, and a discrete to continuum transition at intermediate loads. The model includes all these effects as well as stiffening at large loads as the substrate is encountered. Direct quantitative comparison is made with measurements of a silica foam on a soda-lime glass substrate, strongly supporting the physical basis of the model.

The theories to describe the rate at which electrochemical reactions proceed do not consider explicitly the dimensionality or the occupancy of the energy levels of nanostructured electrodes. It is shown here that the density of states variation in nanoscale electrochemical systems yield novel modulations in the rate constant and concomitant electrical currents. The proposed models extend the utility of presently used Marcus–Hush–Chidsey kinetics to a larger class of materials and could be used as a test of dimensional character. The new models are applied to explain the experimental variation of the electrochemical rate constant of single-layer graphene.

We have prepared stable ultrafine narrow dispersed copper nanoparticles (Cu-NPs) using a facile chemical reduction technique below room temperature (300 K), without any template. X-ray diffraction and high-resolution transmission electron microscopy studies reveal the growth of highly crystalline Cu-NPs with an average diameter of 2.2 nm. Interestingly, these Cu-NPs demonstrate both interband electronic transitions along with usual surface plasmon resonance, a unique phenomenon previously unobserved in any noble metal nanoparticles. These Cu-NPs do not get oxidized easily and could be suitable candidates for different optical devices, heat transfer liquids, and biological applications.

Effective modification of existing supported catalyst has attracted plenty of interests recently. Herein, we introduced ultrasonication to synthesize the palladium-loaded cobalt-based zeolitic imidazolate framework and compared its properties with those using the conventional method. Remarkably, the ultrasonicated frameworks possess 15.33% higher of Brunauer–Emmett–Teller (BET) surface area and 63.37% higher of t-plot external surface area, respectively, which lead up to 23% rise in the degradation of organic pollutants under optimized conditions. Characterizations clearly revealed the causality between ultrasonication, morphology, and catalytic performance compared with their non-ultrasonicated counterparts which further demonstrates a simple but useful method for the modification of supported catalysts.

The understanding of adhesion and survival behavior of bacterial pathogens on implant surfaces are critical to control and reduce implant-associated infections. Herein, the authors investigate the interactions of Staphylococcus aureus, one of the most prevalent causes of implant infections, with Mg–4Zn–0.5Ca implants. It was found that within 60 min of exposure, 99.1% of adherent bacteria were inactivated. The combination of unique mechanical properties, biodegradation kinetics, and antimicrobial characteristics of Mg–4Zn–0.5Ca alloy makes it a promising candidate for future implant applications.

Forty-eight different Ag–Al–Zr ternary alloys were prepared in various compositions to determine the metallic glass region in the Ag–Al–Zr ternary system. Experimental results indicated that the metallic glass region in the Ag–Al–Zr ternary system is Ag20–30Al10–30Zr50–60. The Ag20Al30Zr50 and Ag30Al20Zr50 alloys are supposed to have the best glass-forming ability in the Ag–Al–Zr ternary system. The phase equilibria of the Ag–Al–Zr ternary system at 773 K (500 °C) were investigated and compared with the metallic glass region results in the Ag–Al–Zr ternary system. Ternary isothermal sections of the Ag–Al–Zr system at 773 K (500 °C) were established and two ternary intermetallic phases were observed in this isothermal section.

A model with which to predict the effect of coplanar electrode geometry on diffraction uniformity in photorefractive polymer display devices was developed. Assumptions made in the standard use cases are no longer valid in the regions of extreme electric fields present in this type of device. Using electric-field induced second-harmonic generation through multiphoton microscopy, the physical response in regions of internal electric fields which fall outside the standard regimes of validity were probed. Adjustments to the standard model were made and the results of the new model corroborated through holographic four-wave mixing measurements.

Nanomaterials have been proposed as key components in biosensing, imaging, and drug delivery since they offer distinctive advantages over conventional approaches. The unique chemical and physical properties of graphene make it possible to functionalize and develop protein transducers, therapeutic delivery vehicles, and microbial diagnostics. In this study, we evaluate reduced graphene oxide as a potential nanomaterial for quantification of microRNAs including their structural differentiation in vitro in solution and inside intact cells. Our results provide evidence for the potential use of graphene nanomaterials as a platform for developing devices that can be used for microRNA quantitation as biomarkers for clinical applications.

Solid oxide fuel cells (SOFCs) efficiently generate electricity, but high operating temperatures (T op > 800 °C) limit their utility. Reducing T op requires mixed ion–electron conducting (MIEC) cathode materials. Density functional theory is used here to investigate the role of potassium substitutions in the MIEC material Sr1−x K x FeO3 (SKFO). We predict that such substitutions are endothermic. SrFeO3 and SKFO have nearly identical metallic electronic structures. Oxygen vacancy formation energies decrease by ~0.2 eV when x K increases from 0 to 0.0625. SKFO is a promising SOFC MIEC cathode material; however, further experimental investigations must assess its long-term stability at the desired operating temperatures.

The remarkable broadband and omnidirectional anti-reflectivity observed in the glasswing butterfly arises from the random array of nanopillars present on their wings. In the present study, analogous structures have been replicated on transparent substrates using a scalable, low-cost method that exploits surface dewetting of silver thin films on silica substrates to form an etch mask. Directional etching was applied with high selectivity between Ag and SiO2 using CHF3, allowing large aspect ratios to be achieved with 20 min etches. Single-sided nanostructuring of glass by this method improved the transmission of light by 2–8% for viewing angles of 25°, 45°, and 65°.

The authors carried out matched experiments and molecular dynamics simulations of the compression of nanopillars prepared from Cu|Au nanolaminates with up to 25 nm layer thickness. The stress–strain behaviors obtained from both techniques are in excellent agreement. Variation in the layer thickness reveals an increase in the strength with a decreasing layer thickness. Pillars fail through the formation of shear bands whose nucleation they trace back to the existence of surface flaws. This combined approach demonstrates the crucial role of contact geometry in controlling the deformation mode and suggests that modulus-matched nanolaminates should be able to suppress strain localization while maintaining controllable strength.

Increasing fluorination of organosilyl nitrile solvents improves ionic conductivities of lithium salt electrolytes, resulting from higher values of salt dissociation. Ionic conductivities at 298 K range from 1.5 to 3.2 mS/cm for LiPF6 salt concentrations at 0.6 or 0.7 M. The authors also report on solvent blend electrolytes where the fluoroorganosilyl (FOS) nitrile solvent is mixed with ethylene carbonate and diethyl carbonate. Ionic conductivities of the FOS solvent/carbonate blend electrolytes increase achieving ionic conductivities at 298 K of 5.5–6.3 mS/cm and salt dissociation values ranging from 0.42 to 0.45. Salt dissociation generally decreases with increasing temperature.

Self-assembly of multiferroic oxide composites by chemical and biochemical methodology is discussed. The approach involves covalently attaching organic functional groups or oligomeric DNA/RNA to the nanoparticles (NPs). The organic functional groups are only reactive toward functional groups located on different NPs. Using oligomeric DNA/RNA, one could program NPs to only interact with particles possessing complementary DNA/RNA. We have applied both concepts to the assembly of nanostructures with ferrites for the ferromagnetic phase and barium titanate for the ferroelectric phase. The assembled core–shell particles and superstructures obtained in a magnetic field show evidence for strong interactions between the magnetic and ferroelectric subsystems.

This paper proposes to improve the corrosion resistance of stainless steel using the photocathodic protection (PCP) method with CdS/PbS/titanium dioxide (TiO2) as the photoanode material. Cadmium sulfide (CdS)/lead sulfide (PbS) quantum dot (QD) heterostructure layered on TiO2 enhanced the photoelectrochemical performance and improved the PCP of 304 stainless steel. The photoanode film can protect 304 stainless steel for a period of upto 3 months against corrosion. This work demonstrates that CdS/PbS/TiO2 tandem heterostructure is a promising durable and stable photoanode, which can protect stainless steel in both dark and illuminated conditions.