Graphene due to its unique physicochemical properties mainly its large surface to volume ratio, excellent thermal and electrical conductivity, biocompatibility, as well as broad electrochemical potential, has received considerable attention for biosensing applications. In this review paper, we provide a comprehensive overview of the recent advances in the field of electrochemical biosensors developed using the graphene nanomaterial including graphene oxide, reduced graphene oxide, CVD graphene, and various graphene based nanostructures including nanomesh, nanowalls, etc. in healthcare related applications. The review focusses on material synthesis, device fabrication, and biofunctionalization of graphene electrodes in biosensing such as those based on electrochemical impedance, amperometry/voltammetry, potentiometry, conductometry, and field effect transistor. Additionally, several ingenious biosensing strategies of graphene biosensor in clinical diagnosis for detection of proteins (disease biomarkers), nucleic acids (mutation analysis in genetic diseases), small molecules (disease metabolites like glucose, lactic acid etc.), and pathogens (bacterial and viral infections) have also been discussed.

Diketopyrrolopyrrole (DPP) is a critically important building block that has gained importance in the organic electronics community because of its wide applicability in various devices. In this work, the thiophene flanked DPP moiety attached to alkyl chains of various lengths (this includes straight octyl and branched ethyl hexyl units) has been used as the monomer for electropolymerization. This paper focuses on the study of optical, thermal, solid state ordering and electrochemical properties of these electron deficient monomers using various characterization techniques such as UV–Vis spectrometry (UV), photo-luminescence spectroscopy (PL), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), cyclic voltammetry (CV), as well as ab initio modeling. These monomers exhibit broad absorption spectra from the ultraviolet (280–400 nm) to visible (400–600 nm) regions and emission spectra between 560 and 610 nm. The band gaps of these monomers were calculated to be in the range of 2.00–2.20 eV. These monomers were electropolymerized by scanning the potential between −0.5 and 2.0 V versus ferrocene for up to 50 cycles on a glassy carbon electrode.

Personal, multifunctional, and smart electronic devices/systems are indispensable components of the internet of things for modern information collection and exchange, which play a key role in facilitating the development of human civilization. Traditional technique for powering these sensor nodes mainly relies on batteries, which may not be favorable owing to the limited battery lifetime, large sensor population, wide distribution, as well as the potential of environmental detriment. Extricated from external power sources, triboelectric nanogenerators (TENGs) based active sensors have been extensively spread into a variety of fields for self-powered high-performance sensing, featured as being lightweight, extremely cost-effective, and environmentally friendly. In this article, current progress of TENGs as smart sensors for self-powered touch detection, vibration and acoustic sensing, biomedical applications, as well as human-machine interfacing, has been comprehensively reviewed, from aspects of materials usage, device fabrication to practical applications. The latest representative achievements regarding the TENG based self-powered sensing systems were also systematically presented. In the end, some perspectives and challenges for the TENG based self-powered smart sensors were also summarized.

Some time ago, we reported the synthesis of bixbyite-type V2O3, a new metastable polymorph of vanadium sesquioxide. Since, a number of investigations followed, dealing with different aspects like electronic and magnetic properties of the material, the deviation from ideal stoichiometry or the preparation of nanocrystals as oxygen storage material. However, most of the physical properties were only evaluated on a theoretical basis. Here, we report the lattice dynamics and physical properties of bixbyite-type V2O3 bulk material, which we acquired from physical property measurements and neutron diffraction experiments over a wide temperature range. Besides attributing different possible orientations of the magnetic moments for V1 and V2 to the identified antiferromagnetic (AFM) ground state with a Néel temperature of 38.1(5) K, we use a first order Grüneisen approximation to determine lattice-dependent parameters for the relatively stiff cubic lattice, and, amongst others identify the Debye temperature to be as low as 350 ± 65 K.

In the microsize regime, all crystalline metals studied to-date exhibit a “smaller-is-stronger” size effect. Here, we report an unusual weakest-size phenomenon in the precipitated alloy duralumin 2025, i.e., below a critical size of ∼7 μm, the strength increases as the size decreases, while above this size, the strength increases toward the bulk value with increasing size. At the critical size, strain-hardening is also slowest and the room-temperature creep is fastest. Interestingly, the reduction of strength at the weakest size is more significant for the peak-aged state of duralumin 2025 than its naturally aged state. Theoretical modeling shows that at the weakest size, both strengthening mechanisms of precipitation hardening and dislocation starvation are ineffective. The present results indicate that the conventional wisdom of precipitation hardening is not applicable in the micro-regime, and the common “smaller-is-stronger” understanding is incorrect when material microstructures impose internal length scales that can affect strength.

By reflowing Cu/Sn/Ni ultrafine interconnects under a temperature gradient, a new transient liquid phase (TLP) bonding process was proposed for three-dimensional packaging applications. The evolution of the dominant (Cu,Ni)6Sn5 intermetallic compounds depends strongly on the temperature gradient. The essential cause of such dependence is attributed to the different amounts of Cu and Ni atomic fluxes being introduced into the liquid solder. Under the coupling effect of thermomigration and Cu–Ni cross-interaction, the total atomic flux of Cu and Ni is promoted. As a result, the growth of dense (Cu,Ni)6Sn5 is significantly accelerated and the formation of Cu3Sn is eliminated. The new TLP bonding process consumes only a limited amount of the Ni substrate, but much more from the Cu substrate. The mechanism for the new TLP bonding process is discussed and experimentally verified in this study.

For the first time, valence electron energy-loss spectroscopy (VEELS) was applied to individual single-crystalline SnO2 nanowires to investigate the dielectric function, band gap, and optical absorption coefficient. The results are compared with data from optical techniques such as spectroscopic ellipsometry and UV-Vis, and theoretical calculations from variations of density functional theory. The data obtained agree well with the standard optical and theoretical techniques. The dielectric function and optical absorption coefficient are given up to 20 eV, which otherwise requires a synchrotron source and large single crystals via optical methods. The energy loss function is given up to 40 eV, which gives a useful comparison to previous theoretical studies in an energy range that cannot be achieved via optical measurements. The comparison gives confidence in the accuracy of this method for exploring spatially-resolved measurements in individual nanoparticles or more complex nanostructures that are otherwise difficult to measure accurately using optical techniques.

Surface texture was prepared on the ASTM1045 steel substrate before spraying. Three texturing patterns (groove pattern, square pattern, and hexagon pattern) were acquired by laser processing to investigate the influence of texturing patterns on the adhesion strength of sprayed coatings. The Ni60 coatings were prepared on the textured surface by atmosphere plasma spraying technology. Scanning electron microscopy and laser 3D microscope were used to characterize the morphology of texturing. The adhesion strength between coating and substrate was examined by the tensile test. Image pro plus software was used to calculate the contact area ratio of the textured substrate. The results show that the texturing processed substrates by laser radiation present plain area between two dimples and the protrusion around texturing, and the contact area between coating and substrate is increased. The adhesion strength of coatings with a groove pattern, a square pattern, and a hexagon pattern is 58, 33, and 47 MPa, respectively. The adhesion strength of sprayed coatings varies with the change of the texturing pattern, and it does not only depend on the contact area ratio but also on the texturing density and the texturing microstructure.

Thermal stability up to 400 °C of nanocrystalline (NC) Ni electrodeposits (EDs) with a mean grain size of 28 nm and dispersions of a small amount of CeO2 nanoparticles has been investigated by comparing with two CeO2-free NC Ni counterparts, one with a slightly smaller mean grain size of 18 nm and the other with a slightly larger mean grain size of 34 nm. The results show that the co-deposition of CeO2 particles has dual effects on the thermal stability of the NC Ni EDs, i.e., it promotes the grain growth at the beginning but retards subsequently. It is proposed that the CeO2 co-deposition leads to a decrease in sulfur level and an increase in the plane defects as a result of introduction of incoherent Ni/CeO2 interfaces, which play dominant roles in the grain growth at low temperatures; while the drag effect of CeO2 dispersions becomes dominant at higher temperatures.

Conventional metallic antibacterial materials release metal ions and reactive oxygen species (ROS) for killing bacteria. Herein, we found that nanoporous gold (NPG) exhibits antibacterial activity (AA) at an intermediate relative humidity (RH) of 60% against Escherichia coli and Staphylococcus epidermidis in contrast to the inert behavior of bulk gold. The dependence of AA on RH, morphological observations of bacteria on NPG, and transcriptomic analyses of NPG-treated Escherichia coli were investigated. These observations collectively suggest that biological processes in cell walls containing peptidoglycan and cell membranes are significantly disrupted by direct contact with NPG. Metal ions and ROS were not detected, and therefore are not responsible for the present antibacterial properties of NPG. The catalytic nature of NPG may be responsible for its AA, probably because of lattice distortion at the surface of nanosized ligaments with large curvature.

The development of highly efficient and stable inexpensive catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 in an aqueous solution by utilizing metal-organic frameworks (MOFs) as precursor and template remains a hot topic. Herein, a simple self-template strategy was developed to synthesize a porous nitrogen-doped carbon frameworks embedded with zinc and cobalt nanoparticles (Zn0.3Co2.7@NC) catalyst by thermal annealing of the bimetallic zinc-cobalt zeolitic imidazolate framework (Zn0.3Co2.7-ZIF) as an effective precursor and template. The resulting Zn0.3Co2.7@NC catalysts show an excellent catalytic activity for the reduction of 4-NP and the reduction reaction was completed only in 5 min with nearly 100% conversion. The apparent rate constant for the reaction of 4-NP reduction was estimated to be 0.683 min−1. Moreover, the catalyst was extended to reduce other nitro compounds and exhibited excellent catalytic activity. When compared to other related catalysts in the literature, the catalytic activity of catalyst is superior. Therefore, the resulting Zn0.3Co2.7@NC is expected to get more extensive application in the field of catalysis.

Melanin (from the Greek μέλας, mélas, black) is a biopigment ubiquitous in flora and fauna, featuring broadband optical absorption, hydration-dependent electrical response, ion-binding affinity as well as antioxidative and radical-scavenging properties. In the human body, photoprotection in the skin and ion flux regulation in the brain are some biofunctional roles played by melanin. Here we discuss the progress in melanin research that underpins emerging technologies in energy storage/conversion, ion separation/water treatment, sunscreens, and bioelectronics. The melanin research aims at developing approaches to explore natural materials, well beyond melanin, which might serve as a prototype benign material for sustainable technologies.

In this study, a comparison of the tensile behavior of fully nanotwinned Cu–6 wt.%Al, Cu–2 wt.%Al, and Cu–10 wt.%Ni with stacking fault energies (SFEs) of 6, 37, and 60 mJ/m2, respectively is presented. The samples displayed yield strengths ranging from 830 to 1340 MPa, varying with both alloy content and microstructural parameters. All samples showed low ductility, even though there are tilted twin boundaries present in Cu–10 wt.%Ni. The influence of varying grain width is presented for each alloy and related to both the activation volume and SFE [Figs. 3(a)–3(c)].

In this study, we have developed a facile and simple route for preparation of ultrafine CoO/reduced graphene oxide (rGO) nanohybrids with tunable particle size and crystallinity for lithium-ion battery (LIB) application. At the optimized calcination time of 60 min, the homogeneous and ultrafine CoO nanoparticles with mean size of 4.5 nm can be intimately attached onto rGO surface to rapidly transport Li ions and electrons. The CoO/rGO exhibits excellent rate capability and high specific capacity of 520 mAh/g at 2400 mA/g. In addition, the capacity can be recovered to 900 mAh/g at 150 mA/g after 60 cycles, indicating the superior electrochemical performance of CoO/rGO for LIB applications.

In situ and operando measurement techniques combined with nanoscale resolution have proven invaluable in multiple fields of study. We argue that evaluating device performance as well as material behavior by correlative X-ray microscopy with <100 nm resolution can radically change the approach for optimizing absorbers, interfaces and full devices in solar cell research. In this article, we thoroughly discuss the measurement technique of X-ray beam induced current and point out fundamental differences between measurements of wafer-based silicon and thin-film solar cells. Based on reports of the last years, we showcase the potential that X-ray microscopy measurements have in combination with in situ and operando approaches throughout the solar cell lifecycle: from the growth of individual layers to the performance under operating conditions and degradation mechanisms. Enabled by new developments in synchrotron beamlines, the combination of high spatial resolution with high brilliance and a safe working distance allows for the insertion of measurement equipment that can pave the way for a new class of experiments. Applied to photovoltaics research, we highlight today’s opportunities and challenges in the field of nanoscale X-ray microscopy, and give an outlook on future developments.

In this study, the influence of an externally applied elastic strain on the electrochemical activity of metal film catalysts during the oxygen reduction reaction (ORR) was examined. A novel three-layer specimen, composed of a 10 nm-thick Pt or Pd surface film on a 20 nm-thick Pd70Zr30 metallic glass film that was first deposited on a polymer substrate was used. The intermediate metallic glass layer is instrumental in allowing the top-layer catalytic film to be elastically deformed to a large elastic strain, (up to 2%), enabling a strain effect to be clearly observed. The results consistently show that an applied compressive strain improves the ORR catalytic activity of the Pd and Pt surface layer, while a tensile strain degrades it. These experimental findings are consistent with the prediction of the d-band model, and provide an opportunity to improve the catalytic response during ORR.