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Applications of superhydrophobic (SHS) and lubricant infused surfaces (LIS) involve exposure to corrosive environments from the acidic to the basic, at a range of temperatures, that are not fully characterized. We present for the first time a multifactorial study of the effects of surface fabrication method, surface modification, surface functionalization time, temperature and pH of the immersion medium on the corrosion performance of nonwetting copper surfaces. Bioinspired SHS and LIS fabricated using facile methods of etching and electrodeposition are systematically assessed using potentiodynamic polarization measurements for their corrosion resistance in saline solution ( pH ≈ 7) over a temperature range 23–85 °C. SHS and LIS are shown to exhibit diminished corrosion rate, by up to two orders of magnitude, compared to bare copper surface. An Arrhenius model is developed for the first time, describing the temperature-dependent corrosion rate of SHS and LIS. Electrochemical impedance spectroscopy is used to show that corrosion resistance of LIS is larger by three orders of magnitude in extremely acidic ( pH = 1) and by an order magnitude in extremely alkaline ( pH = 14) media compared to bare copper surface. Etched LIS are generally more resistant to corrosion compared to SHS at all temperatures with excellent microstructural durability.

Currently, owing to the single-molecule-level sensitivity and highly informative spectroscopic characteristics, surface-enhanced Raman scattering (SERS) is regarded as the most direct and effective detection technique. However, SERS still faces several challenges in its practical applications, such as the complex matrix interferences, and low sensitivity to the molecules of intrinsic small cross-sections or weak affinity to the surface of metals. Here, we show an enrichment-typed sensing strategy with both excellent selectivity and ultrahigh detection sensitivity based on a powerful porous composite material, called mesoporous nanosponge. The nanosponge consists of porous β-cyclodextrin polymers immobilized with magnetic NPs, demonstrating remarkable capability of effective and fast removal of organic micropollutants, e.g., ~90% removal efficiency within ~1 min, and an enrichment factor up to ~103. By means of this current enrichment strategy, the limit of detection for typical organic pollutants can be significantly improved by 2~3 orders of magnitude. Consequently, the current enrichment strategy is proved to be applicable in a variety of fields for portable and fast detection, such as Raman and fluorescent sensing., The authors demonstrate a sensing approach for effectively monitoring organic micropollutants in water. They first use mesoporous nanosponge and magnetic nanoparticles for fast enrichment of micropollutants, and demonstrate SERS-based sensing with 2-3 orders of magnitude improvement in detection limits.

The formation of Rb5Ag1/3Zr5/3(MoO4)6 compound during the study of Rb2MoO4-Ag2MoO4-Zr(MoO4)2 system by x-ray diffraction technique was established. Its unit cell parameters, phase transition were determined. The dimensions of trigonal unit cell Rb5Ag1/3Zr5/3(MoO4)6 are a = 10.7235 (3), c = 38.548 (1), V = 3838.9 (3). Temperature and frequency dependences of dielectric parameters for Rb5M1/3Zr5/3(MoO4)6 (M-Ag, Na) ceramics were measured by impedance spectroscopy in the temperature and the frequency range 300-773 K and 1 Hz-10 kHz, respectively. The correlation of dielectric and thermal parameters in the high-temperature region near the phase transition was revealed. Arrhenius plots of the conductivity showed anomalies at high temperatures (723-773 K), increasing several orders of magnitude to 10−3 S K/cm.

Coupling a semiconductor with an electrical insulator in a single amphiphilic nanoparticle could open new pathways for manufacturing and assembling organic electronic devices. Here, a poly(3,4-ethylenedioxythiophene)/polyaniline (PEDOT/PANI) bilayer is confined on the surface of one lobe of snowman-type Janus nanoparticles (JNPs), such that one lobe is semiconducting and the other is electrically insulating. The PEDOT/PANI bilayer is constructed in two synthesis steps, by asymmetric modification of the JNPs with PANI followed by PEDOT. The addition of the PEDOT layer onto the PANI-modified JNPs leads to an enhancement in the conductivity of up to 2 orders of magnitude. Further, we demonstrate that JNPs are very versatile supports for semiconducting polymers because by tuning their size and geometry the overall conductivity of the JNP powders can be modulated within several orders of magnitude.

This paper proposes a novel flexible tactile sensor array for dynamic triaxial force measurement. Piezoresistive nanofibers, which are fabricated via the electrospinning method and are composed of multi-wall carbon nanotubes (MWCNTs) and thermoplastic polyurethane (TPU), are selected as the sensing material. The sensitive piezoresistive layer, which has micron-scale thickness, is wrapped in polydimethylsiloxane (PDMS) with a bumped surface. This structure not only detects triaxial forces of different magnitudes and frequencies, but also can recognize the shape, size, and curvature of external objects using multiple measuring points of the sensor. When the sensor is subjected to normal forces at different frequencies, the measuring voltage shows good responses with variations of less than 1.21 %. When the sensor is subjected to shear forces, the coefficient of variation is less than 2.05%. In addition, when the sensor is stressed at multiple measuring points, the voltage response errors between the different points are less than 5.29%. The sensor shows high sensitivity (with a resistance change that can reach four orders of magnitude) and high response-speeds (response within 62 ms) in validation experiments. The proposed flexible sensor is efficient in triaxial force detection and has the potential for application to prosthetic hands and wearable devices.

Summary Advanced conductors are indispensable circuit elements in modern electronics with unique responses to environmental variations. This work successfully introduces the intriguing polymer relaxation into conductive materials and creates a special rheological conductor (RhC) from liquid metal (LM)-polymer composites. The electrical transition temperatures of RhC are found to be highly consistent with polymer rheological transition temperatures (Tg and Tf). Similar to the time-temperature superposition of polymers, a master curve can be constructed to effectively predict the conductivity of RhC. Further polymer rheological experiments and theoretical analysis successfully demonstrate the relationship between conductance and polymer chain relaxation. The RhC could realize several orders of magnitude change in resistance via temperature/time regulation. The polymer chain dynamics provide multiple resistive responses of RhC to temperature, time, and voltage that are remarkably different from traditional conductors. This work pioneers a new route to re-consider flexible conductors and provides diverse applications in high-tech devices.

Thermoelectric materials have been widely explored for the potential applications in power generation and refrigeration fields. High thermal conductivity (∼500 W/m K) of single-crystal FeSb2 limits the application in cryogenic cooling. In this work, the FeSb2 single crystal has been synthesized by the self-flux method. The rocking curve results reveal that the single crystal possesses quite high crystallinity. The micromorphology image shows that the single crystal is pyknotic without observable pores or cracks. Surprisingly, the thermal conductivity is reduced by 2 orders of magnitude compared with the previous reports, which can be attributed to the enhanced phonon scattering by the defects and impurities. Furthermore, the magnetic field can further suppress the thermal transport by reducing the phonon mean-free path. The maximum suppression rate of the thermal conductivity reaches 14% at 60 K when the magnetic field varies from 0 to 9 T. In this work, we have prepared the FeSb2 single crystal with low thermal conductivity, and the magneto-suppressed thermal transport strategy can be applied to other thermoelectric materials.

Collective behavior widely exists in nature, ranging from the macroscopic cloud of swallows to the microscopic cloud of colloidal particles. The behavior of an individual inside the collective is distinctive from its behavior alone, as it follows its neighbors. The introduction of such collective behavior in two-dimensional (2D) materials may offer new degrees of freedom to achieve desired but unattained properties. Here, we report a highly sensitive magneto-optic effect and transmissive magneto-coloration via introduction of collective behavior into magnetic 2D material dispersions. The increase of ionic strength in the dispersion enhances the collective behavior of colloidal particles, giving rise to a magneto-optic Cotton-Mouton coefficient up to 2700 T-2 m-1 which is the highest value obtained so far, being 3 orders of magnitude larger than other known transparent media. We also reveal linear dependence of magneto-coloration on the concentration and hydration ratios of ions. Such linear dependence and the extremely large Cotton-Mouton coefficient cooperatively allow fabrication of giant magneto-birefringent devices for color-centered visual sensing.

129Xe NMR has been proven to be a powerful tool to investigate the structure of porous materials. Xenon is a monatomic noble gas which could be used as a probe due to the extremely sensitive to its local environment. Optical pumping techniques for production of hyperpolarized (HP) xenon have led to an increase of sensitivity up to orders of magnitude compared with traditional 129Xe NMR. This review summarizes the application of this technique in porous materials and heterogeneous catalysis in recent ten years, involving of zeolites, metal-organic frameworks (MOFs), catalytic process and kinetics.

Ultraviolet photodetectors have several critical applications in communications, early missile launch detection, pollution monitoring, and bacterial fluorescence detection. Wide-bandgap metal oxide semiconductors have proven to be high performance ultraviolet photodetectors with some photoresponsivities reaching several orders of magnitude greater than solid state commercial devices and even photomultiplier tubes. However, analysis and design of metal-oxide photodetectors is complicated by oxygen adsorption and photodesorption at the surface. A limited understanding of this adsorption phenomenon hinders the development of new UV photodetectors. This paper clarifies the adsorption and photodesorption process and makes analysis of metal-oxide photoconductors tractable. Several models of oxygen adsorption, oxygen desorption, and adsorption-controlled conduction from across disciplines are summarized. We discuss each model’s use in their intended context, implications for design, fitting parameters, and limitations. We conclude with an argument that current models are insufficient for describing high-gain metal oxide ultraviolet photodetectors, and we outline the requirements for a new model suitable for high-gain sensors.

This article discusses the absence of methods for measuring low-frequency (LF) fluctuation processes at high temperatures and proposes an original bridge method for measuring the spectra of LF current fluctuations in the tungsten filaments of electric lamps in the controlled temperature range 300–2700 K. The application of the bridge measurement circuit reduces the influence of degradation processes in the filament and the power source’s own noise on the measurement results by several orders of magnitude. A spectral analysis of LF current fluctuations is performed in the frequency range 1.5·10–5–5·10–1 Hz using an automated unit based on a personal computer under the control of specially developed software.

Practical application of surface-enhanced Raman spectroscopy (SERS) is greatly limited by the inaccurate quantitative analyses due to the measuring parameter's fluctuations induced by different operators, different Raman spectrometers, and different test sites and moments, especially during the field tests. Herein, we develop a strategy of quantitative SERS for field detection via designing structurally homogeneous and ordered Ag-coated Si nanocone arrays. Such an array is fabricated as SERS chips by depositing Ag on the template etching-induced Si nanocone array. Taking 4-aminothiophenol as the typical analyte, the influences of fluctuations in measuring parameters (such as defocusing depth and laser powers) on Raman signals are systematically studied, which significantly change SERS measurements. It has been shown that the silicon underneath the Ag coating in the chip can respond to the measuring parameters' fluctuations synchronously with and similar to the analyte adsorbed on the chip surface, and the normalization with Si Raman signals can well eliminate the big fluctuations (up to 1 or 2 orders of magnitude) in measurements, achieving highly reproducible measurements (mostly

In this work, we investigate the dynamics of ion motion in “doubly-polymerized” ionic liquids (DPILs) in which both charged species of an ionic liquid are covalently linked to the same polymer chains. Broadband dielectric spectroscopy is used to characterize these materials over a broad frequency and temperature range, and their behavior is compared to that of conventional “singly-polymerized” ionic liquids (SPILs) in which only one of the charged species is attached to the polymer chains. Polymerization of the DPIL decreases the bulk ionic conductivity by four orders of magnitude relative to both SPILs. The timescales for local ionic rearrangement are similarly found to be approximately four orders of magnitude slower in the DPILs than in the SPILs, and the DPILs also have a lower static dielectric constant. These results suggest that copolymerization of the ionic monomers affects ion motion on both the bulk and the local scales, with ion pairs serving to form strong physical crosslinks between the polymer chains. This study provides quantitative insight into the energetics and timescales of ion motion that drive the phenomenon of “ion locking” currently under investigation for new classes of organic electronics.

Achieving high spinning speed is critical to the production efficiency and viable application of fiber species. Graphene fiber (GF) has recently emerged as a carbonaceous fiber with excellent functionality. However, the extremely low wet spinning speed of GF has limited its applications. We realized high-speed blow spinning of neat GF and fabric by modulating the rheological properties of the graphene oxide (GO) dispersion. We achieved a speed of 556 m min-1, 2 orders of magnitude faster than that for wet spinning. We chose ultrahigh molecular weight polymers as transient additives to circumvent the intrinsic barrier effect of GO and achieve high spinning dope stretchability at low polymer percentages-down to 25 wt %. Minimizing the polymer additive content ensures the high electrical/thermal conductivity of the blow-spun fiber and fabric. This work provides insight into the unique flow properties of 2D sheets and will promote the efficient production of graphene-based fibrous materials.

Ceramic piezoelectric materials have orders of magnitude higher piezoelectric coefficients compared to polymers. However, their brittleness precludes imposition of large strains in mechanical energy harvesting applications. We report here that ice templating affords low bulk modulus lead-free aerogel piezoelectric nanogenerators (PENG) with unprecedented combination of flexibility and high piezoelectric response (voltage and power density). A modified ice templating protocol was used to fabricate piezoelectric nanocomposites of surface modified BaTiO3 (BTO) nanoparticles in crosslinked polyethylene imine. This protocol allowed incorporating a significantly high fraction of BTO particles (up to 83 wt %) in the aerogel, while retaining remarkably high compressibility and elastic recovery up to 80% strain. The output voltage, at an applied compressive force of 20 N (100 kPa), increased with BTO loading and a maximum output voltage of 11.6 V and power density of 7.22 μW/cm2 (49.79 μW/cm3) was obtained for PENG aerogels containing 83 wt% BTO, which is orders of magnitude higher than previously reported values for foam-based piezoelectric energy harvesters. The BTO/PEI PENGs also showed cyclic stability over 900 cycles of deformation. PENGs with higher porosity showed better elastic recovery and piezoelectric properties than lower porosity and higher BTO content aerogels. To the best of our knowledge, this is the first report to demonstrate the piezoelectric properties of high ceramic content aerogels having very high compressibility and elastic recovery.

All-dielectric optical metasurfaces are a workhorse in nano-optics, because of both their ability to manipulate light in different degrees of freedom and their excellent performance at light frequency conversion. Here, we demonstrate first-time generation of photon pairs via spontaneous parametric-down conversion in lithium niobate quantum optical metasurfaces with electric and magnetic Mie-like resonances at various wavelengths. By engineering the quantum optical metasurface, we tailor the photon-pair spectrum in a controlled way. Within a narrow bandwidth around the resonance, the rate of pair production is enhanced up to 2 orders of magnitude, compared to an unpatterned film of the same thickness and material. These results enable flat-optics sources of entangled photons - a new promising platform for quantum optics experiments.

The availability of portable analytical devices for on-site monitoring and rapid detection of analytes of forensic, environmental, and clinical interest is vital. We report the development of a portable device for the detection of biochemiluminescence relying on silicon photomultiplier (SiPM) technology, called LuminoSiPM, which includes a 3D printed sample holder that can be adapted for both liquid samples and paper-based biosensing. We performed a comparison of analytical performance in terms of detectability with a benchtop luminometer, a portable cooled charge-coupled device (CCD sensor), and smartphone-integrated complementary metal oxide semiconductor (CMOS) sensors. As model systems, we used two luciferase/luciferin systems emitting at different wavelengths using purified protein solutions: the green-emitting P. pyralis mutant Ppy-GR-TS (λmax 550 nm) and the blue-emitting NanoLuc (λmax 460 nm). A limit of detection of 9 femtomoles was obtained for NanoLuc luciferase, about 2 and 3 orders of magnitude lower than that obtained with the portable CCD camera and with the smartphone, respectively. A proof-of-principle forensic application of LuminoSiPM is provided, exploiting an origami chemiluminescent paper-based sensor for acetylcholinesterase inhibitors, showing high potential for this portable low-cost device for on-site applications with adequate sensitivity for detecting low light intensities in critical fields.

The present work describes the preparation and the investigation of the room temperature electrical and optical properties of a series of liquid nanocomposites (lnC) prepared with different concentrations of multiwalled carbon nanotubes (MWCNT) in a variety of liquid matrices: glycerin, Vaseline, glucose, propylene glycol and silicone oil (SIO). Special attention is deserved to the SIO matrix, owing to its convenient electrical properties for our purposes. We verified that a small percent fraction of MWCNT dispersed along the SIO matrix is capable of improving the electrical conductivity of the matrix by orders of magnitude, indicating that the MWCNT strongly participates in the electrical conduction mechanism. Also, the application of an external electric field to this lnC resulted in large changes in the optical transmittance, that were interpreted as a consequence of the fieldinduced MWCNT alignment into the liquid matrix. The characteristics of such a new category of nanocomposite in the liquid state suggest further studies.

Understanding electronic and ionic transport across interfaces is crucial for designing high-performance electric devices. The adjustment of work functions is critical for band alignment at the interfaces of metals and semiconductors. However, the electronic structures at the interfaces of metals and mixed conductors, which conduct both electrons and ions, remain poorly understood. This study reveals that a Schottky barrier is present at the interface of the Nb-doped SrTiO3 metal and a LiCoO2 mixed conductor and that the interfacial resistance can be tuned by inserting an electric dipole layer. The interfacial resistance significantly decreased (by more than 5 orders of magnitude) upon the insertion of a 1 nm thick insulating LaAlO3 layer at the interface. We apply these techniques to solid-state lithium batteries and demonstrate that tuning the electronic energy band alignment by interfacial engineering is applicable to the interfaces of metals and mixed conductors. These results highlight the importance of designing positive electrode and current collector interfaces for solid-state lithium batteries with high power density.

Optofluidic biolasers have emerged as promising tools for biomedical analysis due to their strong light-matter interactions and miniaturized size. Recent developments in optofluidic lasers have opened a new Frontier in monitoring biological processes. However, most biolasers require precise recording of the lasing spectrum at the single cavity level, which limits its application in high-throughput applications. Herein, a microdroplet laser array encapsulated with living Escherichia coli was printed on highly reflective mirrors, where laser emission images were employed to reflect the dynamic changes in living organisms. The concept of image-based lasing analysis was proposed by quantifying the integrated pixel intensity of the lasing image from whispering-gallery modes. Finally, dynamic interactions between E. coli and antibiotic drugs were compared under fluorescence and laser emission images. The amplification that occurred during laser generation enabled the quantification of tiny biological changes in the gain medium. Laser imaging presented a significant increase in integrated pixel intensity by 2 orders of magnitude. Our findings demonstrate that image-based lasing analysis is more sensitive to dynamic changes than fluorescence analysis, paving the way for high-throughput on-chip laser analysis of living organisms. Agency for Science, Technology and Research (A*STAR) Nanyang Technological University This research is supported by A*STAR under its AME IRG Grant (project no. A2084c0063). We would like to thank the lab support from Centre of Bio-Devices and Bioinformatics and Internal grant NAP SUG-M4082308.040 from NTU.

Hydrogenation, an effective way to tune the properties of transition metal oxide (TMO) thin films, has been long awaited to be performed safely and without an external energy input. Recently, metal-acid-TMO has been reported to be an effective approach for hydrogenation, but the requirement of acid limits its application. In this work, the reversible and rapid hydrogen doping of WO3 in NaOH(aq) | Al(s) | WO3(s) is revealed by structural and electrical measurements. Accompanied by the structural phase transition identified by in situ X-ray diffraction, the electric resistance of the WO3 film is found to be able to change by 5 orders of magnitude. A significant electrical response of touching, 8-fold in amplitude and 3 s in a cycle, can be achieved in the low-resistance state. These reactions are reversible at room temperature. This study unambiguously proves that the hydrogenation-driven dynamic phase transition of WO3 in metal-solution-WO3 systems could occur not only in acid solutions but also in some non-acid environments. Unlike the monotonic increase of resistance revealed during HδWO3 to WO3 transition, an intriguing non-monotonic evolution was found for crystal lattice parameter c, indicating that the mechanism of WO3 hydrogenation involves a series of metastable states, more comprehensive and reasonable. This work sheds light on the potential applications of metal-solution-TMO hydrogenation in touching sensors, circuits survey, and information storage.

Graphene field-effect transistors (GFETs) are suitable building blocks for high-performance electrical biosensors, because graphene inherently exhibits a strong response to charged biomolecules on its surface. However, achieving ultralow limit-of-detection (LoD) is limited by sensor response time and screening effect. Herein, we demonstrate that the detection limit of GFET biosensors can be improved significantly by decorating the uncovered graphene sensor area with carbon dots (CDs). The developed CDs-GFET biosensors used for exosome detection exhibited higher sensitivity, faster response, and three orders of magnitude improvements in the LoD compared with nondecorated GFET biosensors. A LoD down to 100 particles/μL was achieved with CDs-GFET sensor for exosome detection with the capability for further improvements. The results were further supported by atomic force microscopy (AFM) and fluorescent microscopy measurements. The high-performance CDs-GFET biosensors will aid the development of an ultrahigh sensitivity biosensing platform based on graphene for rapid and early diagnosis of diseases.

This article reports humidity sensors based on hierarchical gallium nitride (GaN) with flower-like microstructures based on a scalable hybrid approach. We have fabricated 3D dandelion flower-like GaN hierarchical microspheres with an ammonothermal- conjugated ammoni- fication method (750-1150 °C) for the humidity sensors. The GaN microspheres are analyzed by scanning electron microscopy, X-ray diffraction, Raman and Fourier-transform spectroscopic methods. It is found that the use of oleylamine in the ammonothermal-ammonification hybrid approach, plays an essential role in the GaN morphology. The GaN sensors are prepared by dip-coating the sensor materials on the interdigitated electrode and their humidity sensing performance have been characterized. The humidity sensing performance is investigated at an applied 1V AC bias, by measuring the impedance and charge transfer resistance as a function of the broad range (10 to 95%) of RH. The GaN sensor exhibits a high response of above four orders of magnitude with excellent linearity and stability within the whole measurement range, while the bare GaN humidity sensors exhibited a low response of less than two orders of magnitude with poor linearity and stability. We have also proposed a possible charge transfer mechanism and studied the influence of the defect degree on the sensing performance of the GaN humidity sensors.

The friction between a molybdenum disulphide (MoS2) nanoflake and a MoS2 substrate was analyzed using a modified Tomlinson model based on atomistic force fields. The calculations performed in the study suggest that large deformations in the substrate can induce a dramatic decrease in the friction between the nanoflake and the substrate to produce the so-called superlubricity. The coefficient of friction decreases by 1–4 orders of magnitude when a high strain exceeding 0.1 is applied. This friction reduction is strongly anisotropic. For example, the reduction is most pronounced in the compressive regime when the nanoflake slides along the zigzag crystalline direction of the substrate. In other sliding directions, the coefficient of friction will reduce to its lowest value either when a high tensile strain is applied along the zigzag direction or when a high compressive strain is applied along the armchair direction. This anisotropy is correlated with the atomic configurations of MoS2.

Electrochemical aptamer-based (E-AB) sensors provide a great opportunity towards the goal of point-of-care and wearable sensing technologies due to their good sensitivity and selectivity. Nevertheless, the output signals from this sensor class remain low when sensors are interrogated via square-wave voltammetry. This low signaling limits the sensor's precision for its capability to detect small changes in target concentrations. To circumvent this, we proposed here the use of a readily shrink-induced, wrinkled Au-coating polyolefin film to immobilize a greater number of DNA probes and thus improve the signaling. Specifically, wrinkled gold film exhibits a 5.5-fold increase of surface area in comparison to the unwrinkled ones. Using these substrates we fabricated a set of E-AB sensors of three biological molecules, including kanamycin, doxorubicin and ATP. We achieved up to 10-fold increase in its current and also good accuracies within ±20% error in the target concentration range across 2 orders of magnitude.

A high-performance Bloch surface wave (BSW) sensor based on the hollow fiber (HF) inner coated with the one-dimensional photonic crystal (1DPC) consisting of TiO2 and SiO2 bilayers is proposed. Performances including sensitivity and figure of merit (FOM) of the sensor are investigated theoretically with the ray transmission model. Several structure parameters such as the center wavelength of 1DPC, the thickness of the cap layer and the bilayer period are optimized to obtain a best performance of the sensor. The results show that the proposed sensor has an ultra-high FOM over 1100 RIU-1, which is approximately two and one orders of magnitude higher than that of the HF surface plasmon resonance (SPR) sensor and HF long-range SPR sensor, respectively. Moreover, the proposed sensor has a much broader practical RI detection range, which makes it more useful in sensing applications. The performance of the proposed sensor applicated in temperature sensing is also estimated to prove its application potential.

With the emergence of stretchable/wearable devices, functions, such as sensing, energy storage/harvesting, and electrical conduction, should ideally be carried out by a single material, while retaining its ability to withstand large elastic deformations, to create compact, functionally-integrated and autonomous systems. A new class of trimodal, stretchable yarn-based transducer formed by coating commercially available Lycra® yarns with PEDOT:PSS is presented. The material developed can sense strain (first mode), and temperature (second mode) and can power itself thermoelectrically (third mode), eliminating the need for an external power-supply. The yarns were extensively characterized and obtained an ultrahigh (gauge factor ∼3.6 × 105, at 10–20% strain) and tunable (up to about 2 orders of magnitude) strain sensitivity together with a very high strain-at-break point (up to ∼1000%). These PEDOT:PSS-Lycra yarns also exhibited stable thermoelectric behavior (Seebeck coefficient of 15 μV K−1), which was exploited both for temperature sensing and self-powering (∼0.5 μW, for a 10-couple module at ΔT ∼ 95 K). The produced material has potential to be interfaced with microcontroller-based systems to create internet-enabled, internet-of-things type devices in a variety of form factors.

The slippery liquid infused porous surface has developed into a potential technology to solve the problem of poor durability in corrosion resistance. Herein, a kind of slippery liquid infused porous surface is created on 7075 aluminum alloy by wire electrical discharge machining for corrosion resistant applications. The hardness of the constructed porous microstructure is similar to the aluminum alloy substrate material, which ensures the stability of the slippery liquid infused porous surface. The modification of low surface energy substance fluorosilane avoids the direct contact between corrosive liquid and porous surface, and improves the lyophobic performance of the porous microstructure surface. The corrosion resistance of the porous microstructure surface is enhanced by the injection of perfluorinated lubricating oil. The experimental results show that the created slippery liquid infused porous surface can display super-slippery properties and durable corrosion resistance. The average sliding velocity of a water droplet is 0.48 ± 0.05 mm s−1 at a sliding angle of 5°. The corrosion current density of the surface is 3.116 × 10−6 A cm−2, which is 2 orders of magnitude lower than that of the polished surface. And the impedance radius reaches 90 kΩ cm2, which is about 20 times that of the polished surface.

A new strategy to achieve long-lived room temperature phosphorescence performance has been developed via the formation of a donor–acceptor structure in a coordination polymer, which features a lifetime (40.22 ms) three orders of magnitude higher than that of pristine phosphor. It also shows remarkable angle-dependent polarized emission.

Control of conductance through a single molecule via alternating anchoring points provides a unique perspective to design single-molecule electronic devices. A high conductance difference among different states is essential for a single-molecule electronic device, which is challenging due to restriction of the structural changes in single-molecule junctions. Here, tetraphenylethylene derivatives with multiple anchoring sites are designed and synthesized to investigate single-molecule conductance using the scanning tunneling microscope break junction (STM-BJ) technique. In the break-junction cycle process, connection conformations with different anchor sites have been achieved reversibly to switch single-molecule conductance using the STM-BJ technique. Through mechanical control, these multi-anchored single-molecule junctions can achieve up to three conductance switching cycles, and the variation in conductance reaches up to four orders of magnitude. Theoretical calculations reveal that the conductance change originates from the different connecting sites and the different anchored configurations of single-molecule junctions provide a significantly different transmission. Our findings provide a reliable strategy to manipulate the mechanical switching and shed light on investigating the intrinsic charge transport of multi-anchored molecules.

A concept of the optimal design of a silicon waveguide based on optically coupled Mie-resonant nanoantennas for efficient inputting of light from point emitters associated with excitons localized at defects in a thin InSe film is proposed. Numerical calculations demonstrate that the efficiency of coupling between a dipole emitter and a resonant silicon waveguide is four orders of magnitude greater than that for a conventional ridge waveguide.

Experimental results of measuring the threshold power density of stimulated emission in coumarin-30 dye solutions with ZnO nanoparticles upon irradiation with femtosecond laser pulses are presented. It is shown that the stimulated emission thresholds of coumarin-30 dye solutions with incorporated ZnO nanoparticles upon irradiation with femtosecond laser pulses are approximately by 3 orders of magnitude higher than the stimulated emission thresholds of coumarin-30 dye solutions with incorporated ZnO nanoparticles irradiated with nanosecond laser pulses.

Nanocrystalline BiFeO3-based powder materials with an average crystallite size near 40 nm have been prepared by solution combustion synthesis from bismuth and iron nitrates using sucrose and tartaric acid as fuel. The materials have been characterized by X-ray diffraction, helium pycnometry, scanning electron microscopy, energy dispersive X-ray microanalysis, and Mossbauer spectroscopy. Magnetometry results demonstrate that the magnetic response of the materials varies over several orders of magnitude, depending on the synthesis procedure.

The development of high-performance glucose sensors is an urgent need, especially for diabetes mellitus diagnosis. However, the glucose monitoring is conventionally operated in an invasive finger-prick manner and their noninvasive alternatives largely suffered from the relatively poor sensitivity, selectivity, and stability, resulted from the lack of robust and efficient catalysts. In this paper, we design a concave shaped nitrogen-doped carbon framework embellished with single Co site catalyst (Co SSC) by selectively controlling the etching rate on different facet of carbon substrate, which is beneficial to the diffusion and contact of analyte. The Co SSC prompts a significant improvement in the sensitivity of the solution-gated graphene transistor (SGGT) devices, with three orders of magnitude better than those of SGGT devices without catalysts. Our findings expand the field of single site catalyst in the application of biosensors, diabetes diagnostics and personalized health-care monitoring.

The efficiency of the laser-induced desorption method as a detector of hydrogen isotopes under pulsed laser irradiation (wavelength 1064 nm, 100 mJ, duration 10 ns) for different power densities of incident radiation on deuterium-saturated thin titanium films was investigated. When the power flow density increases by 16 times, the intensity of the thermal desorption peak increases by more than 2 orders of magnitude. Long-term repeated irradiation of the surface does not lead to significant depletion of the content of hydrogen isotopes in the studied layers, allowing their further ex-situ analysis.

Ion-exchange membranes are critical components of hydrogen fuel cells, where these ionomers can be confined to nanoscale thicknesses, altering the physical properties of these films from that of bulk membranes. Therefore, it is important to develop methods capable of measuring and elucidating the transport mechanisms under thin film confinement compared to bulk Nafion. In this study, water sorption and diffusion in a Nafion thin film were measured using time-resolved in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). Interfacial mass transport limitations were confirmed to be minimal, while restricted water diffusion was observed, where the effective diffusion coefficient of water in the thin Nafion film was many orders of magnitude lower (between 4 and 5 orders of magnitude) than those reported for bulk membranes and was dependent on the initial hydration state of the Nafion. Furthermore, the response of the hydrophobic domains (Teflon backbone) to the swelling of the hydrophilic domains (ionic clusters) was shown to be orders of magnitude slower than that of bulk Nafion.

Atomic force microscopy is employed in the experimental study of specific features of the field emission of electrons from a single silicon needle-type cathode to quasi-vacuum (air). Noncontact regime of the atomic force microscopy is used to measure the I–V characteristics of a single cathode with nanometer-scale tip radius at distances of 10 and 20 nm between the cathode tip and the measurement probe. Electric field distributions are simulated for both surface of the tip of a single cathode and tip surfaces of single cathodes in an array, and the results are used to theoretically estimate electric field enhancement versus cathode–probe distance. It is shown that the enhancement factor calculated from the experimental I–V characteristics in the Fowler–Nordheim coordinates is greater than the result of theoretical calculations by several orders of magnitude. This circumstance indicates that additional quantum dimensional effects that play an important role in the generation of the electron emission current in the nanoscale gap must be taken into account.

The rate-determining step of the photoelectrochemical (PEC) water splitting is the water oxidation reaction at the photoanode, which is 4 orders of magnitude slower than the water reduction reactio...

Freestanding polystyrene thin films were found to reach elongations 2 orders of magnitude larger than what is found in bulk tests. We performed planar tensile testing at multiple strain rates using...

The detection of harmful volatile organic compounds is of great significance to environmental quality and human health. However, it still remains a challenge to achieve high detection sensitivity at a relatively low temperature. Herein, an ultrasensitive catalytic sensor for the detection of triethylamine (TEA) based on ZnO/PtO/Pt nanoarray thin films was realized. Sensor measurements reveal that the PtO/Pt sensitizer dramatically reduces the working temperature from 195 °C of a pristine ZnO sensor to 125 °C of ZnO/PtO/Pt sensors. The ZnO/PtO/Pt sensors exhibit an extremely high response of 3513 to 50 ppm TEA, which is three orders of magnitude higher than that of pristine ZnO. Meanwhile, an ultralow limit of detection of 8.3 ppb is achieved. The outstanding performances are superior to those in most previous reports on TEA detection. Mechanistic investigations reveal that the outstanding performances are ascribed to the strong electronic interaction between PtO and ZnO and the catalytic spillover effect of Pt.

The volumetric concentration of hydrogen in two Brazilian diamonds is determined using secondary ion mass spectrometry and implantation of hydrogen into an external standard sample (with a dose of 1 × 16 at/cm2 and energy of 120 KeV). The diamonds studied differ noticeably in their intensities of IR-active hydrogen from 0 to 1.5 cm–1 according to the analyses of their IR spectra. The results demonstrate that for both samples studied, the volumetric concentration of hydrogen does not exceed the reached detectable level of (1–2) × 1018 at/cm3 or 1.7–3.3 at. ppm; i.e., it is lower by an order of magnitude than in the early chemical analysis and by 2–3 orders of magnitude lower than the results of the ion-beam spectrochemical, nuclear-physical, and ERDA analyses. Only a part of the hydrogen forms optically active impurities in diamond crystals and can be determined by spectral methods.

Additive manufacturing permits innovative soft device architectures with micron resolution. The processing requirements, however, restrict the available materials, and joining chemically dissimilar components remains a challenge. Here we report silicone double networks (SilDNs) that participate in orthogonal crosslinking mechanisms—photocurable thiol-ene reactions and condensation reactions—to exercise independent control over both the shape forming process (3D printing) and final mechanical properties. SilDNs simultaneously possess low elastic modulus (E100%, Additive manufacturing processing requirements pose restrictions on materials and joining chemically dissimilar components. Here the authors use silicone double networks that participate in orthogonal crosslinking mechanisms for independent control of the shape forming process and final mechanical properties.

Oxidation behavior of boron-containing HfC/SiC nanocomposites (SHBC) at temperatures up to 1500 °C and with exposure time up to 100 h was investigated. Two strategies to improve the oxidation resistance of the HfC/SiC ceramics are proposed. First concept involves the incorporation of a small amount of boron (ca. 0.6 wt.%) into the nanocomposite via a single-source-precursor approach, which contributes significantly to the enhancement of its oxidation resistance. Parabolic oxidation rate constants of 10−3 to 10-4 mg2/(cm4 h) at 1300−1500 °C were measured for SHBC and were several orders of magnitude lower than those recorded for boron-free HfC/SiC. The second improvement concept is realized via passivation of the samples upon short-term oxidation at 1400 °C, providing an excellent oxidation resistance over a wide temperature range. This is a crucial step especially when considering the poor oxidation behavior of HfC and the sluggish formation of protective silica scale at moderate temperatures.

This is the first report on the enhanced thermoelectric (TE) properties of novel reaction-temperature (TRe) and duration-induced Bi2S3-Bi nanocomposites synthesized using a facile one-step polyol method. They are well characterized as nanorod composites of orthorhombic Bi2S3 and rhombohedral Bi phases in which the latter coats the former forming Bi2S3-Bi core-shell-like structures along with independent Bi nanoparticles. A very significant observation is the systematic reduction in electrical resistivity ρ with a whopping 7 orders of magnitude (∼107) with just reaction temperature and duration increase, revealing a promising approach for the reduction of ρ of this highly resistive chalcogenide and hence resolving the earlier obstacles for its thermoelectric application potentials in the past few decades. Most astonishingly, a TE power factor at 300 K of the highest Bi content nanocomposite pellet, made at 27 °C using ∼900 MPa pressure, is 3 orders of magnitude greater than that of hot-pressed Bi2S3. Its highest ZT at 325 K of 0.006 is over twice of that of similarly prepared CuS or Ag2S-based nanocomposites. A significantly improved TE performance potential near 300 K is demonstrated for these toxic-free and rare-earth element-free TE nanocomposites, making the present synthesis method as a pioneering approach for developing enhanced thermoelectric properties of Bi2S3-based materials without extra sintering steps.

Nanocrystalline cobalt oxide Co3O4 and composite ZnO/Co3O4 are obtained by chemical deposition from solutions followed by thermal annealing. It is shown that the presence of zinc oxide particles during synthesis radically changes the mechanism of the cobalt carbonates growth, which leads to a change in the phase composition, morphology, and properties of the material. The resistivity of the conducting layers formed from composite ZnO/Co3O4 is three orders of magnitude lower than the resistivity of Co3O4 layers, and composite ZnO/Co3O4 gas sensors demonstrate much higher gas sensitivity than that of control cobalt oxide sensors.

Luminescence lifetime imaging (LLIM) holds great promise in biomedical research owing to its excellent sensitivity and remarkable temporal–spatial resolution, but the development of effective long-lived luminescent probes for LLIM remains an unmet need. Herein, we designed two water-dispersible europium-doped nanoparticles (Eu-D1 and Eu-D2 NPs) for cellular LLIM, showing intense red luminescence emission and an increased lifetime of 4 orders of magnitude (∼56 000 times) than undoped NPs, which could be attributed to the multiple manipulations of their aggregation states, including efficient Forster resonance energy transfer (FRET), suppressed self-quenching, and restrained solvent effects. With good bioavailability, the as-developed NPs were demonstrated as reliable candidates for long-lifetime imaging agents. Such a simple and versatile strategy could be extended to develop various luminescent nanoprobes for advanced high-precision bioimaging.

The impedance and capacitive properties of Pd/oxide/InP structures are investigated at 300 K in the frequency range of 10–1–10–5 Hz in air and in a nitrogen–hydrogen gas medium. The characteristics of structures in both media are interpreted based on a parallel RC-chain model with series resistance. The structure resistance decreases in the presence of hydrogen by three orders of magnitude, while the capacitance increases by 1–3 orders of magnitude depending on the frequency, which is possibly associated with the formation of positively charged centers in the oxide. Hysteresis is found in the capacitance–voltage characteristics in the medium with hydrogen, which is possibly caused by the ionic polarization of centers. It is shown that the total charge of centers measured in units of electrons almost coincides with the number of hydrogen atoms absorbed by palladium.

Organic reactions in microdroplets can be orders of magnitude faster than their bulk counterparts. We hypothesize that solvation energy differences between bulk and interface play a key role in the intrinsic rate constant increase and test the hypothesis with explicit solvent calculations. We demonstrate for both the protonated phenylhydrazine reagent and the hydrazone transition state (TSB) that molecular orientations which place the charge sites at the surface confer high energy. A pathway in which this high-energy form transforms into a fully solvated TSB has a lower activation energy than bulk by some 59 kJ/mol, a result that is consistent with experimental rate acceleration studies.

A family of acrylate-based isotropic Liquid Crystal Elastomers (LCEs) exhibit stress- and strain-optic coefficients orders of magnitude greater than conventional polymeric and photoelastic materials. The three materials, composed of liquid crystalline and nonliquid crystalline monomers, show no nematic phase at any temperature. One of the materials has previously been synthesized with nematic symmetry, but here is instead templated with isotropic symmetry, demonstrating a previously unrealized idea proposed by de Gennes in 1969. Uniaxial strains applied to each material induce nematic ordering which we quantify using dye-absorption spectra and polarized Raman Spectroscopy. We deduce the coupling constants between the nematic liquid crystal order parameter and applied strain varies between 0.37 ± 0.02 and 0.66 ± 0.02—values large compared to other LCE systems. The combination of high strain-optic coefficients (0.048 ± 0.003 to 0.11 ± 0.01) and high compliances (245 ± 18 to 1900 ± 100 GPa–1) demonstrates that isotropic LCEs are exciting candidates for photoelastic coatings for assessing deformations across soft devices and biomaterials.

We have studied the response of graphene-film-based chips on SiC substrates (the relative change in the chip resistance) to coming into contact with fluorescein (C20H12O5) in a wide range of its concentrations in a phosphate-buffered saline solution: from 1 × 10–3 to 1 × 104 ng/mL (seven orders of magnitude). Fluorescein detection seems to be a simple and cheap model experiment to study the sensory ability of graphene in the way of biochips manufacturing. It has been shown that chips with wide terraces on a surface with a step width of about 1000 nm and heights of up to 5 nm made it possible to construct the calibration dependences of chip response on fluorescein concentration.