Polymer:fullerene nanoparticles (NPs) offer two key advantages over bulk heterojunction (BHJ) films for organic photovoltaics (OPVs), water-processability and potentially superior morphological control. Once an optimal active layer morphology is reached, maintaining this morphology at OPV operating temperatures is key to the lifetime of a device. Here we study the morphology of the PDPP-TNT (poly{3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-naphthalene}):PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) NP system and then compare the thermal stability of NP and BHJ films to the common poly(3-hexylthiophene) (P3HT): phenyl C61 butyric acid methyl ester (PC61BM) system. We find that material Tg plays a key role in the superior thermal stability of the PDPP-TNT:PC71BM system; whereas for the P3HT:PC61BM system, domain structure is critical.

Pulsed electric current sintering offers rapid sintering of many materials compared with hot press sintering. Earlier studies had demonstrated that neither sparks nor plasma formation occur in a typical apparatus such as Dr. Sinter™. Hitchcock et al. showed that electromagnetic radio frequency (rf) emission occurred during the pulsing current and suggested this emission was a relevant augmentation to the hot press sintering in addition to the current flow in the specimen. In this report the importance of rf emission in the sintering process is demonstrated and opportunities to further exploit this approach to improve the sintering process are suggested.

UV-initiated crosslinking of electrospun poly(ethylene) oxide (PEO)/chitosan (CS) nanofibers doped with zinc oxide nanoparticles (ZnO-NPs) was performed using pentaerythritol triaclyrate (PETA) as the photoinitiator and crosslinker agent. The influence of the addition of PETA to the PEO/CS diameter and crosslinking of nanofibers was evaluated. The effect of irradiation time on the morphology and swelling properties of the crosslinked nanofibers were investigated. For ZnO-NPs, the minimum inhibitory concentrations were found at 1 mg/mL, and the minimum bactericidal concentrations at 2 mg/mL for all the strains tested. The nanofibrous hydrogel antibacterial effect was tested. This material enters the realm of fibrous hydrogels which have potential use in several applications as in the biomedical area.

The authors report results of the studies relating to the synthesis of nanodot zirconia that has been utilized for the fabrication of electrochemical biosensing platform for the detection of CYFRA-21-1 biomarker, secreted in saliva samples of oral cancer patients. For the synthesis of nanodot zirconia (ndZrO2), the hydrothermal process was used and further functionalized with 3-aminopropyl triethoxysilane (APTES). Electrophoretic deposition technique was employed for its deposition onto the ITO electrode. The EDC-NHS reaction was used for anti-CYFRA-21-1 immobilization and bovine serum albumin (BSA) was used for blocking of the nonspecific binding sites. The fabricated biosensing platform (BSA/anti-CYFRA-21-1/APTES/ndZrO2/ITO) exhibited a wide linear detection range (0.5–50 ng/mL) with excellent sensitivity (0.53 μA mL/ng cm2).

This work established the feasibility of flexible solution-processed radiation sensors prepared from an organic scintillator (1-phenyl-3-mesityl-2-pyrazoline) and a biocompatible semiconducting polymer (violanthrone-79). Absorbance, steady-state, and time-resolved photoluminescence measurements demonstrated a high efficiency for the transfer of absorbed energy from the scintillator to the semiconductor. Blended nanoparticles containing both materials were fabricated in order to reduce the intermolecular distance between molecules, creating a highly efficient energy transfer pathway. Radiation-sensing devices were then constructed from the materials. These exhibited successful sensitivity for gamma radiation from a 137Cs source that was not present for the control semiconducting polymer alone.

In this work, a facile superhydrophobic coating for 2024-T3 aluminum alloy is developed and characterized. The corrosion resistance of the coating was analyzed. The results showed that the coating has high polarization resistance and a low corrosion rate. Furthermore, a micro/nanoscale investigation about the interaction between substrates and the corrosive environment was carried out using the in situ atomic force microscope technique. The change in surface topography was monitored for both the bare aluminum alloy substrate and the superhydrophobic aluminum alloy. The results showed that the coating retained surface features indicated that the coating has excellent corrosion resistance.

In situ small-angle x-ray scattering (SAXS) is used to investigate the electrochemical durability of Pt-Metal (Pt-M) catalysts sputtered onto nitrogen-modified high surface area carbon powder. The results demonstrate that nitrogen modification promotes catalyst durability through reduction of nanoparticle dissolution and coarsening. Although particle sizes of Pt-M on high surface area carbon supports can be difficult to determine with transmission electron microscopy (TEM), a novel SAXS method has been employed to calculate particle size. SAXS analysis shows that the Pt-M nanoparticle size distribution remained stable for 3000 electrochemical cycles after nitrogen modification, whereas the unmodified support material leads to Pt-M nanoparticle instabilities. These results for industrial-relevant catalyst/support architectures underscore the potential of nitrogen-modified carbon support structures for enhanced Pt-M catalyst durability.

Nanoindentation-induced phase transformations in both crystalline silicon (c-Si) (100) and ion-implanted amorphous silicon have been studied at temperatures up to 200 °C. The region under the indenter undergoes rapid volume expansion at temperatures above 125 °C during unloading, which is indicated by “bowing” behavior in the load–displacement curve. Polycrystalline Si-I is the predominant end phase for indentation in crystalline silicon whereas high-pressure Si-III/Si-XII phases are the result of indentation in amorphous silicon. We suggest that the Si-II phase is unstable in a c-Si matrix at elevated temperatures and can directly transform to Si-I during the early stages of unloading.

The incorporation of small amounts of phenolic antioxidants, such as 2,6-di-tert-butyl-4-cresol and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], into photovoltaic organo-lead halide perovskite layers significantly suppressed the degradation of the perovskite compounds via light irradiation in the presence of ambient oxygen. While the facile incorporation of the antioxidants did not decrease both the quality of the formed perovskite crystal grains and the photovoltaic conversion performance of the cells, it enhanced the antioxidizing property and water repellency of the perovskite layer owing to the elimination of superoxide anion radical and hydrophobic molecular structure and improved the durability of the cells.

Cellular activity upon osmotic stress is related to the occurrence of several disease conditions. The real-time monitoring of the cell response to this kind of stress can give insight into the comprehension of mechanisms involved in cellular shrinkage. Currently the dynamics of the osmotic stress is studied using dedicated and tricky methodologies, not suited to the in vivo testing. We show that a disposable electronic device is very effective for studying the early stage of the osmotic stress induced on human lung adenocarcinoma cells, A549, by a hyperosmotic environment. Our findings corroborate the experimental results obtained by a standard complementary analysis.

Many materials systems comprise complex structures where multiple materials are integrated to achieve a desired performance. Often in these systems, it is a combination of both the materials and their structure that dictate performance. Here the authors layout an integrated computational–statistical–experimental methodology for hierarchical materials systems that takes a holistic design approach to both the material and structure. The authors used computational modeling of the physical system combined with statistical design of experiments to explore an activated carbon adsorption bed. The large parameter space makes experimental optimization impractical. Instead, a computational–statistical approach is coupled with physical experiments to validate the optimization results.

We present a first-principles investigation on the optical absorption of tungsten trioxide, an electrochromic material. Using state-of-the-art techniques, the absorption spectra are calculated for the cubic, monoclinic, and amorphous phases. For both crystalline and disordered structures, doping induces strong absorption in the infrared. Absorption in the visible range increases with the degree of structural distortion; the absorption coefficient in the blue exceeds 103 cm−1 at doping levels above 1020 cm−3 in the monoclinic phase. Increased disorder in disordered structures significantly enhances the visible-range absorption. We identify the microscopic mechanism as optical absorption originating at conduction-band-derived states that are filled by doping.

A method for rapid quantitative imaging of dopant distribution using secondary ion mass spectrometry (SIMS) is described. The method is based on SIMS imaging of the cross-section of a reference sample with a known concentration profile. It is demonstrated for the case of boron quantification in silicon in a SIMS imaging mode. A nonlinear relationship between the secondary ion intensity and the concentration is observed. A detection limit of 3 (±2) × 1017 at./cm3 (~6 ppm) is determined with 39 nm pixel-size for the used experimental conditions. As an application example, a boron concentration profile in a passivating contact deposited on a textured Si surface is analyzed.

We study strain fields and deformation patterns produced by wedge indentation of metals using high-resolution imaging, image correlation and simulation. A long-standing problem associated with simulation of narrow angle wedge indentation is overcome by introducing a weak form of the symmetry boundary conditions. The simulated deformation fields show good agreement with experiment. Based on strain localization, three distinct modes of deformation largely cover the range of wedge angles. Importantly, narrow angle wedge indentation is characterized by intense strain localization at points close to the free surface and thus offers a possible new tool to probe strain gradient effects.

Clathrates based on Si and Ge have very low lattice thermal conductivity (~1 W/m-K). This value can potentially be further reduced by alloying and nano-structuring. In this work, the thermal conductivity of Si and Ge clathrates alloy have been investigated using model based on the relaxation time approximation. By including alloy scattering, we find that the lattice thermal conductivity of Ba8Cu6Si40 is reduced by 50% from 1.64 to 0.80 W/m-K in Ba8Cu6Si40(1−x)Ge40x alloy. Further ~90% reduction of the thermal conductivity is possible for nanowire clathrate alloys. The ultra-low thermal conductivity in the nanowire will be very suitable for the thermoelectric application.

Ab initio microkinetic modeling was performed to study ethanol conversion to acetaldehyde on Pt-based bimetallic alloys in a non-oxidative environment. Alloying Pt with Au, Ag, Cu, Co, Ni, Zn, Cd, Al, Ga, In, Tl, Ge, Sn, Pb, As, and Sb showed an increase in product turnover by at least an order of magnitude compared with Pt at 423 K. This was correlated to the increased stabilization of CH3CHO species over these alloys. Among the alloy candidates; Pt3Cu, Pt3Zn, Pt3Ga, Pt3Ge, Pt3Sb, and Pt3Pb were found to be more active than Pt.

This work is based on a recent theoretical study of how the hydrostatic pressure and core/shell sizes affect the optical properties associated with the transition from the ground state to first excited state (1s–1p), of an exciton confined in spherical core/shell quantum dots (SCSQDs). We have computed under an effective mass framework, linear, third-order nonlinear, and total absorption coefficients (AC) and refractive index (RI) as functions of photon energy for different sizes of SCSQDs with varying hydrostatic pressure. Our results show that the optical absorption is deeply dependent on the incident light intensity. Both AC and RI significantly influenced by the confinement and pressure effects.

The narrow bandgap of Ag2S quantum dots was used to decorate TiO2 nanotube arrays (TiO2 NTAs) by the successive ionic layer adsorption and reaction (SILAR) method to enhance its photoelectrochemical performance. The micromorphology of the photoanode films prepared by the SILAR under different parameters (including different cycle times, capillary spot sample, and ultrasound-assisted) was systematically analyzed. The photoanode film Ag2S/TiO2 prepared by the SILAR under the ultrasound-assisted method shows Ag2S evenly distributed in TiO2 NTAs. At the same time, the corresponding photoabsorption range has been extended to the visible area, while the photocurrent density and photoconversion efficiency have been increased to ~1.8 mA/cm2 and 0.6%, respectively.

Pseudo-line tensions are used in a continuum approach to simulate contact angle hysteresis. A pair of pseudo-line tensions in the receding and advancing states, respectively, are utilized to represent contact line interactions with a substrate because of the nanoscale topological and/or chemical heterogeneity on the substrate. A water droplet sitting on a horizontal or inclined substrate, whose volume is 4–30 µL, has been studied experimentally and numerically. Our simulation model predicts consistent hysteresis at four different droplet sizes compared with experiments. Meanwhile, the critical roll-off angles captured in simulations match well with experiments.

Dual-stage, constant loading-rate followed by constant-load, pyramidal indentation experiments were performed to investigate the strain-rate (10−5–10−1/s) and temperature (295–573 K) dependence of pure magnesium. The estimated total activation energy, Q (0.69–1.01 eV), and apparent activation volume, V* (17–28b3), indicate that plastic deformation is controlled by a dislocation cross-slip mechanism. The results from this work and previous studies confirm that, during pyramidal indentation of Mg, the operative deformation mechanism remains the same over a very wide strain-rate and temperature range.