Operational lifetime is a critical performance parameter of organic electronic devices and can be cut short by multiple degradation mechanisms. One supposed cause is metal migration between the electrodes, which, however, is difficult to study independently of other failure modes. We present a setup, which excludes such competing processes and demonstrates that silver (Ag) electrochemical migration through organic optoelectronic materials occurs predominantly by cation transport. Metal dendrites form at the cathode, eventually causing short circuits between the electrodes. Lifetime studies with organic light-emitting diodes containing Ag electrodes suggest that results obtained with our setup can provide relevant information about degradation in real devices.

Cellulose nanocrystal (CNC) enhances mechanical performance of cement composites via short-circuit diffusion (SCD). CNCs transport water along their hydrophilic surface into the unhydrated cement cores to induce extra hydration. It is important to characterize CNC distribution because it determines the SCD pathways. This study for the first time, employs virtual environment dynamic atomic force microscopy, an atomic force microscopy computational tool to investigate CNC distribution in both fresh and hardened cement pastes. The methods not only provide insights in a static context (hardened sample), but also offer opportunities to evaluate the interaction of CNCs with calcium-silicate-hydrate growth during the kinetic early ages of hydration.

Thorium dioxide (thoria, ThO2) is used in refractory applications and as nuclear fuel. Its melting temperature, the highest of any binary oxide, makes it a difficult system to process. Here we report on the effects of flash sintering on the densification of thoria. We found 95% of theoretical density is obtained at ~950 °C (~30% of the melting temperature) with an electric field of 800 V/cm. Variation in power density had a minimal effect on the densification. Scanning electron microscopy images show the effects of flash sintering on grain size as a function of electric field.

A novel microfabrication technique for microelectrode arrays (MEAs) with a full diamond–cell interface is demonstrated. Boron-doped nano-crystalline diamond (BNCD) is used as a conductive electrode material on metal tracks insulated by intrinsic NCD. MEAs successfully recorded spontaneous electrical activity in rat primary cortical neuronal cultures. Patch-clamp measurements show no alterations to cell membrane passive properties or active firing response, for cell developing ex vivo on diamond. Impedance analysis revealed low impedance magnitude of BNCD electrodes, suitable for multi-unit neuronal recordings. Additionally, the impedance phase of the fabricated electrodes shows a high degree of capacitive coupling, ideal for neuron stimulation.

Applying sufficient tensile strain to Ge leads to a direct bandgap group IV semiconductor, which emits in the mid-infrared (MIR) wavelength range. However, highly strained-Ge cannot be directly grown on Si because of its large lattice mismatch. In this work, we have developed a process based on Ge micro-bridge strain redistribution intentionally landed to the Si substrate. Traction arms were then partially etched to keep locally strained-Ge micro-blocks. Large tunable uniaxial stresses up to 4.2% strain were demonstrated in Ge, which was bonded on Si. Our approach allows envisioning integrated strained-Ge on Si platform for MIR-integrated optics. Silicon photonics merge optical and electronic components that can be integrated together onto a single microchip.

The synthesis of egg-white (EW) capped silver nanoparticles (NPs) was carried-out in a one-step reaction using crude EWs, which is a reagent that can be easily found. These NPs were applied for the colorimetric detection of Hg2+ ions in solution. The results showed a blue shift of the surface plasmon absorption due to the decrease in Ag NP size upon incorporating Hg through the formation of an Ag–Hg amalgam shell. The probe was used for the selective determination of Hg2+ ions in tap water with excellent selectivity and sensitivity with a detection limit of about 300 nM.

New ionic conjugated polyelectrolyte complex films based on poly(3,4-ethylenedioxythiophene):sulfonated poly(diphenylacetylene) (PEDOT:SPDPA) are electrochemically formed on indium thin oxide substrates using a potentiostatic method, and their physical properties are evaluated using various analytical tools. Depending on a constant applied voltage, the surface morphological features and electrochemically doped states are different due to the conformational structure related to the oxidation state in the PEDOT growth process and concomitant SPDPA doping state in the films. For the purpose of use as a hole injection layer in organic light-emitting diodes, a well-known configuration (ITP/PEDOT:SPDPA/TPD/Alq3/LiF/Al) is adopted to investigate the optoelectronic properties.

Spherical Sn0.3Ag0.7Cu (wt.%) solder droplets with diameter ranging from 70.6 to 334.0 µm were prepared using pulsated orifice ejection method. Compared with conventional atomization, these droplets are almost completely spherical with a much narrower size distribution. The surface of these droplets is smooth without detectable satellite particles. Furthermore, both the composition and microstructure are homogenous throughout any single droplet regardless of their size. Detailed microstructural analysis shows that nano-sized Ag3Sn particles are distributed homogenously in the β-Sn matrix. The results suggest that the droplets have advantage as electronic packaging material and be a promising candidate material for three-dimensional printing.

We deposited TaWSi amorphous metal thin films to determine how composition affects film crystallization and oxidation at high temperatures. Films were deposited by magnetron sputtering from targets of nominal compositions Ta : W : Si = 40 : 40 : 20, 30 : 50 : 20, and 30 : 30 : 40, and studied by electron probe microanalysis, electron microscopy, electrical methods, x-ray diffraction, x-ray photoelectron spectroscopy, and atomic-force microscopy. All films remained amorphous to 800 °C or higher temperatures. Films prepared from the target composition 30 : 30 : 40 yielded the film composition Ta41.7W38.4Si19.9, which retained its film integrity and amorphous structure to 1100 °C, even after annealing in air.

In our paper, yttrium aluminum garnet doped with cerium (YAG:Ce) and terbium aluminum garnet doped with cerium (TAG:Ce) yellow garnet phosphors were prepared by a modified sol–gel method, using oxide, nitride as raw materials and acetylacetone, dimethyl sulfoxide, cetrimonium bromide in the hydrolysis and condensation step. The thermal treatment of the phosphors was performed at 1100 °C in order to transform it from amorphous to crystalline garnet phase. Structural, morphological, and luminescence properties were studied by Fourier transform infrared spectrometry, x-ray diffraction, scanning electron microscopy, and fluorescence spectroscopy. The results show that the modified sol–gel method provides a feasible approach to produce YAG:Ce and TAG:Ce yellow phosphors for the optoelectronic applications.

The effect of p-type doping at ultra-low concentrations (~10−4–10−5 monomer mol fraction) of the polymer poly(3-hexylthiophene) (P3HT) is studied using charge modulation (CM) spectroscopy. Quantitative analysis of CM spectra of doped P3HT show that dopants induce measurable changes in the P3HT local chain conformation. We find that the dopants reside in both the aggregate and amorphous regions of the polymer, not just in the amorphous regions, as previously assumed. With increased doping, the P3HT intrachain disorder grows, causing the P3HT chains to become more oligomer-like, which we postulate leads to the drop in mobility commonly observed in literature.