Two semiconductors (Cu2O and TiO2) were chosen for the photocatalytic reduction of bicarbonate to formate in order to perform a systematic study on the effect of six different hole (h+) scavengers. The six h+ scavengers selected for the study include glycerol, ethylene glycol, 2-propanol, sodium sulfite, triethanolamine, and ethylenediaminetetraacetic acid. Glycerol proved to be the most efficient h+ scavenger, and TiO2 in glycerol showed the highest quantum efficiency of 5.04 ± 0.3%. This finding bodes well as a sustainable one because glycerol is environmentally benign, a low-cost material, and is derived from plants, as opposed to petroleum sources like 2-propanol or ethylene glycol.

Due to the lack of the stability of amine films, a promising transducer, quartz-tuning fork (QTF) prongs were modified by a bi-layer film of plasma-polymerized n-heptane (hep) and then by ethylenediamine (EDA), respectively. For this purpose, the authors investigate the stability of amine-rich thin films both in air and aqueous medium. EDA films were deposited on QTF substrates by using an RF plasma system. The final amine-rich thin film was used to immobilize biologic recognition element. Model protein studies were showed that selected thin films could be adapted to QTF transducers to be used as a biosensor template.

We present a quantitative in-situ transmission electron microscope (TEM) study of stress-assisted grain growth in 75 nm thick platinum thin films. We utilized notch-induced stress concentration to observe the microstructural evolution in real time. From quantitative measurements, we find that rapid grain growth occurred above 290 MPa of far field stress and ~0.14% elongation. This value is found to be higher than that required for stable interface motion but lower than the stress required for unstable grain boundary motion. We attribute such grain growth to geometrical incompatibility arising out of crystallographic misorientation in adjoining grains, or in other words, geometrically necessary grain growth.

Polymeric electrolytes have attracted recent research interest because they offer the advantages of being safe and non-flammable, having no dendrite formation, and having no possibility of leakage. The incorporation of synthetic polymers to gel electrolytes has numerous disadvantages: for instance, the required preparation time for creating gel electrolytes from synthetic polymers is dubious and lengthy. Additionally, the conventional pristine polymer gel electrolyte layer has been reported to have low ionic conductivity. This work is focused on preparing a thin flexible gel electrolyte layer by using a naturally occurring wood-based nanofiber cellulose (NFC) hydrogel, to overcome the energy and time consumption of conventional processes. In addition, we use polyvinyl alcohol (PVA) as an additive to the NFC hydrogel in controlled amounts to fabricate a stable thin gel electrolyte layer. By using x-ray diffraction, optical microscopy, and Fourier transform infrared spectra studies, we were able to further our understanding of the microstructure of the films: i.e., the penetration and cross-linking (changes in the bonding structures) of semi-crystalline PVA and hydrogel to form a flexible gel electrolyte layer. The NFC hydrogel-PVA films resulted in much higher ionic conductivity values when compared to other existing pristine polymer electrolytes. The addition of KOH to the NFC hydrogel-PVA further enhanced the ionic conductivity. The best ionic conductivity recorded was 75 mS/cm for films with thickness in the range of 200–350 µm, which is comparable to the highest reported ionic conductivity values of gel electrolytes.

This work presents the recent progress in the development of the concurrent atomistic-continuum (CAC) method for coarse-grained space- and time-resolved atomistic simulations of phonon transport. Application examples, including heat pulses propagating across grain boundaries and phase interfaces, as well as the interactions between phonons and moving dislocations, are provided to demonstrate the capabilities of CAC. The simulation results provide visual evidence and reveal the underlying physics of a variety of phenomena, including phonon focusing, wave interference, dislocation drag, interfacial Kapitza resistance caused by quasi-ballistic phonon transport, etc. A new method to quantify fluxes in transient transport processes is also introduced.

Amine-based plasma polymer thin films (NH2-PPTFs) are favorable due to their potential ability for binding a variety of biomolecules, especially in biotechnologic studies. In this context, to understand the effect of different amine sources on quartz tuning forks’ (QTF) surface functionalization and isolation, we prepared PPTFs by single-step plasma polymerization process. The amino-group concentration of PPTF's was proportionally increased by increasing discharge powers, whereas not affected from exposure time. It was observed that the resistivity increased with the increasing molecular weight of the precursor. In conclusion, NH2-PPTF-modified QTFs present as a great candidate for future biotechnologic applications.

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.

Effective degradation of organic pollutants in wastewater is of great importance to the environment and human society. TiO2-based electrospun nanofibrous materials combining the properties of the large specific surface area, high aspect ratio, tunable compositions and structures, as well as easy to recycle, show great promise for the efficient removal of organic pollutants. In this Prospective paper, the recent progress in the degradation of organic water contaminants over visible-light-responsive TiO2-based nanofibrous materials is summarized, with emphasis on the strategies for improving the visible-light photocatalytic activity of TiO2-based nanofibrous materials. Finally, the current challenges and future outlook in this field are discussed.

The selectivity of catalyst is an essential factor in direct methanol fuel cells (DMFCs) and plays an important role to improve their performance. To this end, platinum (Pt)-based low-cost trimetallic catalysts have been developed. The catalyst comprising ultra-low Pt-decorated NiCu bimetallic alloys nanoparticles fabricated on reduced graphene oxide (rGO). The series of Pt-NiCu/rGO nanocomposites were synthesized with different compositions to obtain the optimal conditioned material. The electrochemical results showed good performance for the electro-oxidation of methanol at anodic end of DMFCs. These outcomes opened up a broad avenue for developing lower cost-active catalysts with better performance for DMFCs.

A variety of applications from insulation to catalytic supports can benefit from lightweight, high surface area, mesoporous materials, which maintain their mesoporous structure to temperatures of 900–1200 °C. Silica aerogels begin to densify by 700 °C. Alumina aerogels are capable of higher temperature exposure than their silica counterparts, but undergo successive phase transformations to form transitional aluminas prior densifying to α-alumina. The present study characterizes the phase transitions of aluminosilicate aerogels derived from Boehmite powders to elucidate the role of time and temperature on phase transitions, surface area, and morphology. Aerogel compositions stable to 1200 °C for periods of 24 h have been demonstrated.

The origin of ionic conductivity in bulk lithium lanthanum titanate, a promising solid electrolyte for Li-ion batteries, has long been under debate, with experiments showing lower conductivity than predictions. Using first-principles-based calculations, we find that experimentally observed type I boundaries are more stable compared with the type II grain boundaries, consistent with their observed relative abundance. Grain boundary stability appears to strongly anti-correlate with the field strength as well as the spatial extent of the space charge region. Ion migration is faster along type II grain boundaries than across, consistent with recent experiments of increased conductivity when type II densities were increased.

We report that an electron beam focused for high-resolution imaging rapidly initiates observable crystallization of amorphous Me–Si–C films. For 200-keV electron irradiation of Nb–Si–C and Zr–Si–C films, crystallization is observed at doses of ~2.8 × 109 and ~4.7 × 109 e−/nm2, respectively. The crystallization process is driven by atomic displacement events, rather than heating from the electron beam as in situ annealing (400–600 °C) retains the amorphous state. Our findings demand a critical analysis of alleged amorphous and nanocrystalline ceramics including reassessing previous reports on nanocrystalline Me–Si–C films for possible electron-beam-induced crystallization effects.

A great challenge in the field of neurocomputing is to mimic the brain behavior by implementing artificial synapses and neurons directly in hardware. This work shows that a Leaky Integrate and Fire (LIF) artificial neuron can be realized with a two-terminal device made of Mott insulator thin films. Polycrystalline thin films of the well-known Mott insulator oxide (V0.95Cr0.05)2O3 were deposited by magnetron sputtering and patterned with micron-scale TiN electrodes. These devices exhibit a volatile resistive switching and a remarkable LIF behavior under a train of pulses suggesting that LIF artificial neurons may be realized from (V0.95Cr0.05)2O3 thin films.

In this work, we present an oxygen-releasing insole to treat diabetic foot ulcers. The insole consists of two layers of polydimethylsiloxane: the top layer has selective laser-machined areas (to tune oxygen permeability) targeting the ulcerated foot region, while the bottom layer provides structural support and incorporates a chamber for oxygen storage. When loaded with a pressure of 150 kPa (average value for standing/walking), the insole is able to release oxygen at a rate of 1.8 mmHg/min/cm2. At lower sitting pressures, the delivery rate persists at 0.092 mmHg/min/cm2, raising the oxygen level to an optimal healing value (50 mmHg) for a 2 × 2 cm2 wound within 150 min.

Electronically active block polymers based on π-conjugated macromolecules have been investigated for applications where nanostructured electrodes are of prime import; however, controlling the nanoscale order of these materials has proven challenging. Here, we demonstrate that diblock copolymers that utilize a non-conjugated radical polymer moiety as the electronically active block assemble into ordered thin-film nanostructures. Specifically, the diblock copolymer polydimethylsiloxane-b-poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PDMS–PTMA) was synthesized via atom transfer radical polymerization to generate polymers with readily controlled molecular properties. Importantly, solvent annealing of the PDMS–PTMA thin films led to well-defined nanostructures with domain spacings of the order of ~30–40 nm.

Unconventional techniques to benefit from the low-cost and high-efficiency monocrystalline silicon solar cells can lead to new device capabilities and engineering prospects. Here, a nature-inspired spherical solar cell is demonstrated, which is capable of capturing light three-dimensionally. The proposed cell architecture is based on monocrystalline silicon and is fabricated using a corrugation technique. The spherical cell shows an increase in power output by up to 101% with respect to a traditional flat cell with the same projection area using different reflective materials. Finally, the spherical cell shows advantages in terms of enhanced heat dissipation and reduced dust accumulation over conventional cells.

We report results of the studies relating to the development of the emerging nanostructured molybdenum trioxide (nMoO3)-based biocompatible label-free biosensing platform for breast cancer detection. The structural and morphological studies of the synthesized nMoO3 nanorods were investigated by XRD, SEM, X-ray photoelectron spectroscopic, and TEM techniques. This biocompatible one-dimensional (1D) nMoO3-based biosensing platform exhibited high sensitivity (0.904 µAmL/ng/cm2), wide linear detection range (2.5–110 ng/mL), and a lower detection limit as 2.47 ng/mL toward human epidermal growth factor receptor-2 detection. The results obtained using this sensor platform on serum samples of breast cancer patients were validated using ELISA.

Using time-resolved laser-scanning confocal microscopy and ultrafast optical pump/THz probe spectroscopy, we measure photoluminescence (PL) and THz-conductivity in perovskite micro-crystals and films. PL quenching and lifetime variations occur from local heterogeneity. Ultrafast THz-spectra measure sharp quantum transitions from excitonic Rydberg states, providing weakly bound excitons with a binding energy of ~13.5 meV at low temperatures. Ab-initio electronic structure calculations give a direct band gap of 1.64 eV, a dielectric constant of ~18, heavy electrons, and light holes, resulting in weakly bound excitons, consistent with the binding energies from the experiment. The complementary spectroscopy and simulations reveal fundamental insights into perovskite light-matter interactions.

In this work, using density functional theory we study electronic and atomic structure as well as redistribution of ions at the interface between cubic-Li7La3Zr2O12 (LLZO) (001) and LiCoO2 (LCO) (10–14). It is found that a large lattice-mismatch-induced compressive strain of ~12% at the interface leads to disordering of LLZO (001). However, even a large tensile strain of ~13.5% does not influence ordering of LCO (10–14). Li ions tend to move from the surface of LCO and bulk LLZO to occupy the interstitial sites at the topmost layers of the LLZO slab. Li ion transfer from LCO to LLZO accompanies with electron transfer from the former to the latter and the formation of gap states.

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.