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Surface-enhanced Raman scattering (SERS) technique can increase the Raman signals of the analytes owing to the electric field enhancements on the nanostructures. The strong light intensity, called photonic nanojet, can be formed at the backlight of the dielectric microstructures. Recently, some researchers have applied the photonic nanojets in SERS. In this paper, a layer of synthesized low-cost polystyrene microspheres with the average of small particle size of 4.26 μm and high refractive index 1.5875 was prepared by dispersion polymerization method and coating on metal nanopillars SERS substrates using air-water interfacial floating method, and it was applied to improve the Raman signal sensitivity of kinetin (6-furfurylaminopurine) which is one kind of plant growth regulators and can function an effective compound for improving plant stress tolerance. The Raman intensity increased from 841 to 4449 for the Raman shift at 1327 cm−1, about 5.29 times stronger. The SERS experiments using the kinetin of ultralow concentrations are measured and it shows that femto Molar can be measured. The numerical simulations indicated that the enhancement factor was about 4 times for plane wave illumination and 3.1 times for focused Gaussian beam. It has considerable potential for different analytes in sensing applications.

Since the discovery of glare illuminators, considerable efforts have been devoted to achieving a breakthrough of high light intensity on the order of magnitude. In this paper, we prepared strong flash blinding agents for the first time by using aluminum powder, oxidant, and adhesive as the main materials, and tris-(8-hydroxyquinolinato) aluminum (Al2q3), triazoindolizine, or nano zinc oxide, etc. as electronic output brightener after mixing and granulation according to the developed formulation. It was discovered that the luminescence intensity was related to the thermal effect of the substance while the brightener only served as an auxiliary brightening effect to achieve energy non-destructive conversion. With the same formula, the luminescence intensities of glaze agents with ADN and potassium perchlorate as oxidants were slightly higher than that of ammonium perchlorate oxidant; the brightening effect of nano-zinc oxide was slightly higher than those of tris-(8-hydroxyquinolinato) aluminum (Al2q3) and triazoindolizine. The luminescence intensity of the substance with a high thermal effect value was high, but the luminescence time was slightly short. Under identical conditions, the luminescence effect of nano-aluminum powder was obviously better than that of micro-aluminum powder with the highest luminescence intensity of 3.9 × 1010 ~ 1.9 × 1011 cd and the luminescence time of 39 - 48 ms. The effects of shell material and structure and the effect of heat-induced mode on the luminescence intensity were also investigated. The luminescence intensity of the glare agent with a high shell strength was high, but the luminescence time was slightly short. Moreover, the energy level of the brightener is excited under the induction of high temperatures, which leads to a blue shift to promote the chemical reaction of the material in a favorable direction. Finally, the optical radiation of the thermally induced high-temperature combustion system was analyzed from the aspects of thermal effect, combustion temperature, and chemiluminescence effect. A way to improve the optical radiation intensity of a high-temperature combustion system was proposed.

The biocompatible hydrogel materials are used for the fabrication of artificial cornea. The refractive index of the hydrogel material can affect the optical quality of the artificial cornea. It is challenging to measure the refractive index of the hydrogel material because it is between solid and liquid status during the fabrication processes. In this work, we propose using the Shack–Hartmann wavefront sensor system to measure the wavefront images and to calculate the corresponding aberrations of optical material. The wavefront aberrations can be used to estimate the refractive index of the optical material. To prove the concept, the standard N-BK7 bi-convex lenses with focal lengths of 100 and 150 mm at wavelengths 780, 532, and 450 nm have been measured, and the results show that the relative errors of the average measured refractive indices are about 0.1%–0.17%. We used this proposed method to measure the refractive index of the P407-DA hydrogel material. We found that the average measured refractive indices of the P407-DA hydrogel material are 1.3175, 1.3516, and 1.3645 at wavelengths 780, 532, and 450 nm, respectively. Compared with the refractive index of human cornea, the P407-DA hydrogel can be used as the artificial cornea material. The Cauchy dispersion formula can be used to calculate the Abbe number of the P407-DA hydrogel material, which is about 11, lower than the human cornea’s Abbe number. It means that the P407-DA hydrogel material has higher chromatic dispersion than the human cornea material. Moreover, the elasmobranch (shark) corneas, which are known as the suitable material for xenotransplantation, are measured by the Shack–Hartmann wavefront sensor system. The ABBE refractometer (ATAGO DR-M4) is used to measure the flat P407-DA hydrogel sample and it is found that the refractive index is slightly different when compared with the measured results by the Shack–Hartmann wavefront sensor system. The refractive indices of other biocompatible hydrogels poly(acrylic acid) (PAA) and poly(2-hydroxyethyl methacrylate) (PHEMA) are also measured by our proposed method, and it is found that the refractive index of P407-DA is more suitable for designing corneal samples than other hydrogels. It is found that the refractive indices of the elasmobranch corneas are similar to the P407-DA material. Our proposed method to measure the refractive index of hydrogel material using the Shack–Hartmann wavefront sensor system is useful. It is a non-contact, minimally invasive, and time-efficient method for shaped structures. The results can be used as a guide for developing better biocompatible material for artificial cornea.

Molecular dynamics (MD) simulations are conducted to systematically benchmark the effects of molecular weight, chain number, and cooling rate on the glass transition temperature (Tg) and coefficient of thermal expansion (CTE) of poly(ethylene oxide) (PEO). Hyperbolic regression as an objective identified method is used to extract Tg and CTE. The results show that for a cooling rate higher than 5 × 1013 K/min, Tg and CTE are both strongly affected by rapid quenching. For a cooling rate lower than 5 × 1013 K/min, Tg and CTE in the high-temperature domain still slightly depend on the cooling rate. Eventually, to eliminate the finite size effect of the model, a threshold molecular weight of 11,240 g/mol should be satisfied in the system. In addition, the chain number must be more than 10, at least for an oligomer system (50 monomers). This study comprehensively reveal the critical parameters of poly(ethylene oxide) (PEO) in the MD simulation that causes the numerical effect on polymer simulation and the variation of thermodynamics property. The threshold value of total molecular weight of 11,240 g/mol must be satisfied, which leads the polymer that exhibits its steady state bulk properties. For the oligomer system (Mw

In this study, we have investigated the annealing effects on FeTe0.55Se0.45 single crystals in S and Te atmospheres. FeTe0.55Se0.45 single crystals were prepared by self-flux method. The as-grown sample shows a rather broad superconducting transition temperature around 6 K and low superconducting volume fraction, which is due to the relatively low proportion of superconducting phase. After being annealed in different vapor atmospheres, their superconducting properties, such as superconducting transition temperature, critical current density Jc, and superconducting volume fraction, could be greatly improved. All experimental results suggest that the bulk superconductivity of FeTe0.55Se0.45 single crystals can be obtained after annealing and thus present another option to remove the excess Fe, which paves the way for further practical application.

In this letter, temporal evolution of plasma density is characterized in the time-domain using a low-power THz frequency-comb radiator in the 130-nm SiGe BiCMOS process. The frequency-comb radiator covers from 10 s of GHz up to 1.1 THz where the spacing between tones is programmable and can be set by the frequency of an external trigger signal to as high as 10.5 GHz. Due to the complex permittivity of plasma, electromagnetic waves experience a phase and amplitude change as they pass through the plasma. The THz-pulse radiator used in this letter is locked to a low-phase noise external source. Hence, the phase-noise of the radiated tones is extremely low, which enables detecting small phase changes. In this measurement, phase and amplitude changes of THz waves are captured from 333 to 495 GHz for different plasma parameters by varying gas pressure, plasma pulse rate, and plasma excitation power.

Cu1.8S has been considered as a potential thermoelectric (TE) material for its stable electrical and thermal properties, environmental benignity, and low cost. Herein, the TE properties of nanostructured Cu1.8S1−xTex (0 ⩽ x ⩽ 0.2) bulks fabricated by a facile process combining mechanical alloying (MA) and room-temperature high-pressure sintering (RT-HPS) technique were optimized via eliminating the volatilization of S element and suppressing grain growth. Experimentally, a single phase of Cu1.8S was obtained at x = 0, and a second Cu1.96S phase formed in all Cu1.8S1−xTex samples when 0.05 ⩽ x ⩽ 0.125. With further increasing x to 0.15 ⩽ x ⩽ 0.2, the Cu2−zTe phase was detected and the samples consisted of Cu1.8S, Cu1.96S, and Cu2−zTe phases. Benefiting from a modified band structure and the coexisted phases of Cu1.96S and Cu2−zTe, the power factor is enhanced in all Cu1.8S1−xTex (0.05 ⩽ x ⩽ 0.2) alloys. Combining with a drastic decrease in the thermal conductivity due to the strengthened phonon scatterings from multiscale defects introduced by Te doping and nano-grain boundaries, a maximum figure of merit (ZT) of 0.352 is reached at 623 K for Cu1.8S0.875Te0.125, which is 171% higher than that of Cu1.8S (0.130). The study demonstrates that doping Te is an effective strategy to improve the TE performance of Cu1.8S based materials and the proposed facile method combing MA and RT-HPS is a potential way to fabricate nanostructured bulks.

With the demand of flat panel display development, utilizing the non-volatile memory devices based on indium-gallium-zinc-oxide (IGZO) film may be integrated with IGZO thin film transistors (TFTs) to accomplish system-on-panel applications. In this work, 1 × 1 μm2 via hole structure IGZO based memory device was fabricated and the resistive switching (RS) behavior was investigated. By inserting a nitrogen doping layer IGZO:N by plasma treatment in Pt/IGZO/TiN device, highly improved RS performance including lower forming voltage, remarkable uniformity, large memory window of 102, retention property of 104 s at 125 °C, excellent pulse endurance of 107 cycles were achieved. The X-ray photoelectron spectroscopy analysis indicates that plasma doping method can evenly dope nitrogen and induce more non-lattice oxygen in the IGZO film. It is deduced that the N atoms of the inserting layer can influence the random formation of oxygen vacancy type conducting filaments, which results in more stable and uniform performance.

This research compared and analyzed the adaptation of four evapotranspiration equations: the FAO56 Penman-Monteith (PM), Priestley-Taylor, Hargreaves-Samani and Thornthwaite equations by using the day-to-day meteorological data of the 42 observation stations in the Pearl River basin. Numberical simulation of the four equations in different seasons and regions was made in order to find out the most suitable one for the evapotranspiration estimate in the Pearl River basin. Results show that the calculation results of the PM equation seem more stable in different seasons and regions, and is closer to the actual observation, due to the detailed consideration of the effects of aerodynamics and energy supply on evapotranspiration in its calculation procedure. The missing data of relative humidity, sunshine duration, wind speed and air pressure would have influence on the calculation accuracy of the PM equation. Temperature can be used to instead of the above variable in the PM equation, which is called the PMT equation. The applicability and the calculation accuracy is explored in this study. And the results show that the calculation results of the PMT equation is larger than those of the PM equation. By setting a correction coefficient in the PMT equation, the calculation accuracy can be obviously improved. Therefore, in the absence of other data, the PMT equation calculated only using temperature data can be use as an ideal equation for the evapotranspiration calculation and research in the Pearl River basin.

Recently, theoretical work predicted that the cobalt mono-antimonide (CoSb) with a NiAs-type structure could be stabilized in the form of a monolayer PbO-type FeSe structure on a $\mathrm{SrTi}{\mathrm{O}}_{3}$ substrate [Ding et al., Phys. Rev. Lett. 124, 027002 (2020)], which may host high-temperature superconductivity comparable with monolayer FeSe [Wang et al., Chin. Phys. Lett. 29, 037402 (2012)]. Motivated to explore the possible pressure-induced superconductivity in bulk CoSb associated with structural instability, utilizing the diamond anvil cell technique, we herein report a comprehensive study of the electrical transport, crystalline structure, and electronic band structure of the bulk CoSb with electrical conductivity, synchrotron x-ray diffraction, and first-principles calculations. No pressure-induced superconductivity is detected down to 2 K with pressure up to 42.0 GPa, but a structural phase transition occurs between 11.7 and 16.2 GPa. Instead, an electronic transition, featured by a carrier-type switch from an electron $l10\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$ to a hole ($n\ensuremath{\rightarrow}p$) dominant one at higher pressure, is observed. The $n\text{\ensuremath{-}}p$ switch at room temperature is ascribed to a pressure-induced structural phase transition from hexagonal ($P{6}_{3}/mmc$, No. 194) to orthorhombic ($Pnma$, No. 62), which is confirmed by a combination of first-principles calculations and structural refinement. Interestingly, the temperature-driven $p\text{\ensuremath{-}}n$ switch also occurs in the orthorhombic phase at \ensuremath{\sim}90 K, emphasizing the tunable multiband structure (with charge neutrality point) of the semimetal CoSb by pressure or temperature. Moreover, the electronic transition is assigned as a semimetal-semimetal transition. The resistivity shows a robust ${T}^{3}$ dependence trend $l30\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ for both semimetal phases. At high temperature, all the $\ensuremath{\rho}(T)$ curves become saturated, as described by the parallel-resistor model. The results support that the $s\text{\ensuremath{-}}d$ interband scattering dominates the conductivity of both the hexagonal and orthorhombic phases under pressure. The superconductivity absence implications are discussed, assuming the electron-phonon interaction in CoSb drives the superconductivity.

We developed an efficient and convenient electrochemical method to synthesize π-conjugated redox metal-complex linear polymer wires composed of azobenzene-bridged bis(terpyridine)metal (2-M, M = Fe, Ru) units covalently immobilized on glassy carbon (GC). Polymerization proceeds by electrochemical oxidation of bis(4′-(4-anilino)-2,2′:6′,2″-terpyridine)metal (1-M) in a water–acetonitrile–HClO4 solution, affording ultralong wires up to 7400 mers (corresponding to ca. 15 μm). Both 2-Fe and 2-Ru undergo reversible redox reactions, and their redox behaviors indicate remarkably fast redox conduction. Anisotropic hetero-metal-complex polymer wires with Fe and Ru centers are constructed via stepwise electropolymerization. The cyclic voltammograms of two hetero-metal-complex polymer wires, GC/[2-Fe]–[2-Ru] (3) and GC/[2-Ru]–[2-Fe] (4), show irreversible redox reactions with opposite electron transfer characteristics, indicating redox diodelike behavior. In short, the present electrochemical method is useful to synthesize polymer wire arrays and to integrate functional molecules on carbon.

Electrical performances, output stability and use of comfort are three crucial indexes for the rapid advancements in wearable power generators. However, there exist few studies that can simultaneously improve the three aforementioned indexes in a simple manner. Here, a bio-inspired Trimurti poly(vinylidene fluoride) (PVDF) tribo-material with a transcendent electrical performance, excellent output stability in high environmental humidity, and increased use of comfort under a sweating condition is designed, by simple self-assembly of electro-pore-creating. The nanoporous cancellous-bone-like, hydrophobic lotus-leaf-like, and hydrophilic root-xylem-like structures are assembled respectively in the interior, on the upper surface and on the bottom surface of Trimurti PVDF mat, endowing the fabricated Trimurti triboelectric nanogenerator (T-TENG) with outstanding electrical performances and availability in different application environments. With a high power density of 10.6 W m−2, the T-TENG can directly drive 714 light-emitting-diodes and small electronics. Additionally, under the relative humidity of 85%, the output retention rate of the T-TENG reaches up to 22%. Under the simulated sweating condition, the Trimurti PVDF mat can absorb sweat into its bottom region to accelerate evaporation of sweat. This work indicates a substantial progress of wearable high-performance power sources for dealing with various complex conditions in practical applications.

Triboelectric nanogenerators (TENGs) have received much attention due to their potential application in driving portable electronics. Despite the fast development of this technology, improving their performances in a simple manner still remains a great challenge. In this work, a heart-like micro-nanofiber based wearable triboelectric nanogenerator (HMN-TENG) with high performances is demonstrated. The three-dimensional (3D) secondary heart-like structure is designed and self-assembled on an electrospun poly(vinylidene fluoride) (PVDF) fiber based tribonegative layer, and this structure can match the depressed porous and ravine-like structures on the tribopositive layer. The HMN-TENG delivers the voltage, current density and power density outputs of up to 1063 V, 97 mA m−2 and 14.8 W m−2, respectively. The high outputs stem from the joint effect between the heart-like structure and the porous structure, which enlarges the effective contact area via their high surface roughness and the “occlusion effect”. Furthermore, the practicability of the HMN-TENG is verified by driving 595 light-emitting diodes (LEDs), a scientific calculator and a timer. The washability is proved by comparing its voltages before and after washing ten times as well as soaking in water for a week. The design offers a solution for performance enhancement of wearable TENGs, and the approach presents a simple and cost-effective technology.

Selector is considered as a promising solution to solve sneak-path current for high-density 3-Dimensional (3D) memories. However, bidirectional selector with fast speed and long lifetime is still extremely needed. In this work, 2D material of graphene oxide containing epoxide, hydroxyl and carboxyl (-COOH, -OH, >C=O) is assembled with HfO2 to form a flexible bi-layer selector. Interestingly, the selector exhibits excellent uniformity, fast switching speed (~160 ns) and remarkable endurance of ~5×108 cycles. Moreover, no performance degradation is observed for more than 103 times with the bending radii ranging from 40 mm to 20 mm. The high uniformity and excellent endurance may be attributed to the insulating interface layer at the HfO2/GO interface, which plays a vital role on the connection/disrupt of conductive filament (CF). Thus, the incorporation of GO into HfO2 selector may be a feasible way to achieve a promising HfO2-based selector, which have potential applications in high-density 3D integration for flexible electronics.

Exploring stimuli-responsive luminescent materials is still an urgent need for fabricating smart nanodevices. Herein, by taking advantage of the aggregation-induced emission (AIE) effect originating from nonconventional chromophores, stimuli-responsive fluorescent silica nanoparticles (SiO2-NH2-F) have been facilely constructed without adding any fluorophores. The SiO2-NH2-F can not only provide fascinating blue emission but also contrasting fluorescence and shape-transforming responses to acidic pH and high temperature. Significantly, the nanostructure and stimuli-responsive fluorescence properties of SiO2-NH2-F could be further tuned using a tetraphenylethene (TPE)-functionalized carboxylate gemini surfactant (N16-TPE-N16). Owing to its unique chemical-structure, surface-activity, pH-sensitivity and fluorescent properties, the designed N16-TPE-N16 can not only serve as an ingenious “additive” to regulate the construction of SiO2-NH2-F in the structure-directing process but also provide anchored fluorophores and chromophores to improve its original photoluminescence. By appropriately tuning the concentration of N16-TPE-N16, shape-controlled fluorescent silica nanoparticles (AIE-SNs-F) can be prepared directly, producing three different types of silica nanorods (AIE-300-F, AIE-400-F and AIE-600-F). In particular, the incorporated N16-TPE-N16 will further endow the AIE-SNs-F with enhanced fluorescence intensity, especially for longer wavelength bands (up to 3.7-fold), accompanied by improved sensitivity to acidic pH and temperature. The developed AIE-SNs-F integrates two kinds of AIE characteristics into a single system, opening up a new avenue for the controllable fabrication of multifunctional fluorescent nanomaterials.

The availability of metrology solutions, one of the critical factors to drive leading-edge semiconductor devices and processes, has been confronted with difficulties in advanced nodes. For developing new metrology solutions, high-quality test structures fabricated at specific sizes are needed. Electron-beam direct-write lithography has been utilized to manufacture such samples. However, it can encounter significant-resolution difficulties and may require complicated process optimization in sub-10-nm nodes. Therefore, we investigate the feasibility and patterning control of metrology test structures fabricated by helium ion beam (HIB) direct milling and HIB direct-write lithography, where HIB has the sub-nm resolution in nature. Results show that features down to 5 nm are resolvable without any resolution enhancement technique by HIB direct milling. For HIB direct-write lithography, features down to International Roadmap for Devices and Systems 1.5-nm node are also resolvable without optimization from the lithography simulation. Furthermore, patterns beyond the 1.5-nm node can be achievable with the help of the proximity effect correction technique. Preliminary results demonstrate that HIB direct milling and HIB direct-write lithography can be a promising alternative for fabricating pit-type programmed defects (PDs) and bump-type PDs, respectively. In conclusion, HIB is suggested to be a potential tool to fabricated test structures for developing advanced metrology solutions in sub-7-nm nodes.

In order to solve the accuracy problem of the conventional microgripper causing by the external vibration for the connecting power supply with wires, a novel opto-electrostatic repulsive actuation mechanism and mode for driving microgripper is proposed, which can achieve remotely non-contact control and wireless energy transfer. Firstly, the principle of opto-electrostatic repulsive mechanism is presented and introduced, the opto-electrostatic repulsive force activated by PLZT ceramic is derived. To obtain the maximum tip displacement of microgripper, the opto-electrostatic repulsive actuated unit is optimized. Based on which the parameters of the proposed light operated microgripper are determined, and then the optimized unit is simulated by COMSOL software.

Among all the iron-based superconductors, the 11 series has the simplest layered structure but exhibits rich physical phenomenon. In this work, we have synthesized Fe1-xCoxS single crystals with tetragonal structure and studied their structure and magnetic properties. Magnetic susceptibility measurements indicate that the cobalt doping would suppress superconductivity and even introduce weak ferromagnetism besides antiferromagnetism. Scanning electron microscopy study reveals that the Co-doped samples exhibit intrinsic phase separation. Moreover, magnetic force microscopy measurement shows no magnetic domain in Fe1-xCoxS, indicating that neither phase is pure ferromagnetic. The coexistence of ferromagnetism and antiferromagnetism leads to the relatively large exchange bias field. Since the exchange bias effect has been widely used in the field of information storage, spin-valves, and magnetic tunnel junctions, our study provides another option for further application.

GeTe-based alloys have drawn increasing attention because of the excellent thermoelectric (TE) performance and potential applications in mid-temperature range. Although reducing carrier concentration by aliovalent doping plays an important role in maximizing the TE performance of GeTe alloys, modulating the intrinsic Ge vacancies is also indispensable. In this work, the intrinsic Ge vacancies of GeTe crystals were suppressed by the synthesis process of temperature gradient cooling technique (TGCT) and Bi-Sb co-doping. The later aliovalent doping also derives a facilitated band convergence, enhanced density-of-state effective mass, and maintained carrier mobility with optimized carrier concentration, along with enhanced phonon scattering from the fluctuations of mass and strain. Benefiting from enhanced electrical properties and reduced thermal conductivity, Ge0.91Bi0.06Sb0.03Te achieved a maximum ZT of 1.9 at 753 K, together with a comparable average ZT of 1.14 at 300–773 K. The results reveal the potential of the TGCT fabrication and Bi-Sb co-doping on enhancing TE performance of GeTe-based alloys with a strengthened suppression of Ge vacancies.

In this paper, the influence of antenna height on microwave propagation in evaporation duct is investigated, both from numerical simulation and experimental observation. Comparisons of microwave propagation with different antenna heights under different conditions, such as different evaporation duct heights (EDHs) and signal frequencies, are presented. At distinct conditions, the corresponding optimal antenna heights are not the same. When the EDH is low, microwaves cannot be trapped and propagate in the evaporation duct layer. The higher the antenna height, the smaller the path loss. For the case when the evaporation duct can trap microwaves well, a low antenna is more suitable for the propagation of microwaves in the evaporation duct layer. However, the optimal antenna height varies for different EDHs and frequencies. The influence of antenna height on microwave propagation was observed in the experiment held in the northern part of the South China Sea in December 2013. The experiment result shows that under good evaporation duct conditions, the path loss at antenna height 3 m are 10 dB lower in average than that at 6 m.

Detecting the emitted vapors from overheated polyvinyl chloride (PVC) cables has proven to be an effective way to monitor early electrical fires. In this work, the vapors generated from both conventional and phthalate-free PVC cables were first examined. 2-ethylhexanol (2-EH) was found to be ubiquitously present and can serve as a universal signature gas for the overheated cables. Sea urchin-like ZnO was then prepared via a template-free hydrothermal route for sensing 2-EH. A facile immersion-calcination method was adopted to further modify ZnO, and different CuO/ZnO and Cr2O3/ZnO composites were obtained. The surface modification led to significant improvement in the response of the ZnO sensors to 2-EH. Cable fire simulation tests were also conducted to evaluate the response of optimized gas sensors to overheated conventional and phthalate-free cables in comparison with a typical smoke detector.

The system of suspended gold nanoring on silicon nanotube substrate with enhanced light harvesting and electromagnetic field enhancements was proposed in the present study. The effects of outer/inner diameter (D/d) ratio of the ring and tube on the plasmonic behavior were studied by systemic simulations and experiments. In simulations, the high order quadrupole–dipole mode was also excited in addition to the typical dipole–dipole mode, and the resonant configurations were characterized by both electric field profile and resonant surface charge distribution. Experimentally, both dark-field and Raman microscopies were conducted to examine the plasmonic behavior. The plasmon-enhanced scattering could be controlled by tailoring the D/d ratio, and the dark-field image colors could be manipulated covering the visible range. Raman spectra using two excitation wavelengths were also recorded and showed good agreement with calculated enhancement factor which, in turn, provided the evidence of the evolution of reson...

In this work, tungsten thin films were deposited on different substrates by magnetron sputtering and some of the films were then annealed at 1000°C for 1 hour in order to investigate the influence of different processing parameters on morphology and microstructure of films. Scanning electron microscope and x-ray diffraction were used to detect the morphology and microstructure of films. Under the same conditions, the thin films on different substrates showed different preferred grain orientations although the morphologies were similar. After thermal treatment, the morphology of films changed significantly and the total stress parallel to film surfaces dropped off sharply.

Large-scale silver nanobelts (AgNBs) were prepared by a one-step method at near room temperature with high catalytic activity for 4-nitrophenol (4-NP) reduction to 4-aminophenol. This strategy was simple and green owing to the reasonable application of sodium carboxymethylcellulose (CMC) as a structure-directing agent and ascorbic acid (AA) as a reducing agent, avoiding extreme temperatures, tedious procedures, environmentally unfriendly additives, organic solvents and complicated apparatus. Most AgNBs reached lengths of 50 μm with some reaching ∼86 μm; these AgNBs were produced from large round nanoplates with thicknesses of ∼58 nm. By tuning the CMC concentration, AgNO3/AA ratio and temperature, the product morphology changed from one-dimensional nanobelts to three-dimensional pie-like, brick-like and hierarchical microstructures. Benefiting from their slender and unique laced structure, the AgNBs showed superior catalytic activity for 4-NP reduction. Additionally, the reaction rate constant and activity factor of the AgNBs reached 1.74 × 10−2 s−1 and 87.00 s−1 g−1, respectively (∼11.75, 6.61 and 8.13 times higher than the activities of the pie-like, brick-like and hierarchical Ag microstructures). This method not only successfully prepared AgNBs using a simple, green approach, further broadening the application of CMC to control metal nanomaterial morphologies, but may also be applied to the preparation of other kinds of nanomaterials.

Bacteria such as Acinetobacter baumannii (AB) can cause serious infections, resulting in high mortality if not diagnosed early and treated properly; there is consequently a need for rapid and accurate detection of this bacterial species. Therefore, we developed a new, nitrocellulose-based microfluidic system featuring AB-specific aptamers capable of automating the bacterial detection process via the activity of microfluidic devices composed of magnetic-composite membranes. Electromagnets were used to actuate these microfluidic devices such that the entire diagnostic process could be conducted in the integrated microfluidic system within 40 minutes with a limit of detection as low as 450 CFU per reaction for AB. Aptamers were used to capture AB in complex samples on nitrocellulose membranes, and a simple colorimetric assay was used to estimate bacterial loads. Given the ease of use, portability, and sensitivity of this aptamer-based microfluidic system, it may hold great promise for point-of-care diagnostics.

Controlling the structure, morphology, and composition of noble metals is of great significance to improve the catalytic activity and stability of catalysts. Herein, we have successfully synthesized self-interconnecting Pt-Cu alloy nanowire networks (NWNs) with controllable compositions via the co-reduction of the metal precursors potassium chloroplatinate (K2PtCl6) and CuCl2 with sodium borohydride (NaBH4). Owing to the hydrogen bubbles formed by NaBH4 hydrolysis and oxidation as a dynamic template, the facile strategy was carried out without any organic solvent, capping agent, polymer, or special experimental device, ensuring that the surfaces of NWNs were definitely "clean". The performance of the as-prepared Pt-Cu alloy NWNs for the reduction of 4-NP was dramatically improved compared with that of pure Pt NWNs and the commercial Pt/C catalyst. Particularly, the PtCu NWNs with a Pt/Cu atomic ratio of 1 : 1 exhibited excellent catalytic activity and reusability for the reduction of toxic 4-NP. The reaction rate constant and activity factor of the PtCu NWNs reached 1.339 × 10-2 s-1 and 66.95 s-1 g-1, respectively, which were dramatically better than those of pure Pt NWNs (11.5-fold) and commercial Pt/C (13-fold). The superior catalytic activity and reusability can mainly be attributed to the clean surface, the synergistic effect of Cu and Pt atoms and the self-interconnecting nanowire network structure.

The paper adopts modified carbon fiber with Meldrum's acid and silane coupling agent (KH-550), then add the modified carbon fiber to the paper based friction materials. The paper aims to explore the changes of modified carbon fiber in its surface structure and properties by electron microscopy and infrared spectral analysis, and the effect of anionic microparticle forming retention aid system comprised of lithium soapstone-cationic polyacrylamide (CPAM) on mechanical properties and retention of paper based friction materials. Compared with the addition of unmodified carbon fiber to paper based friction materials, the addition of modified carbon fiber with Meldrum's acid, silane coupling agent, Meldrum's acid and silane coupling agent enhance the tensile strength of paper based friction materials. The tensile index of paper based friction materials was separately enhanced by 64.87 %, 91.38 % and 28.88 %. Compared with the paper based friction materials without the anionic microparticle forming retention aid system, the basis weight of paper based friction materials increased by 13.97 %.

For the ferroelectric polymer, poly (vinylidenefluoride-co-trifluoroethylene)(PVDF-TrFE), the enhanced secondary crystallization above Curie temperature has been evaluated able to prevailingly yield drawing effects on dangling chains of dispersed crystals, and thus results in crystal association and sequential coalescence. Multiple thickening of lamellar crystals and in-between amorphous regions are identified therefore. As the balance of mutual drawing among evolving crystals is able to be gradually reached, rarely recognized self-regulated assembly of polymer crystals occurs, which eventually led to several-micrometer spread of oriented stacking arrays of lamellar crystals. As a result, considerable in-between molecular segments are enduringly stretched, and aligned electric dipoles are thus widely created by applied electric fields. The dipolar polarization of both ferroelectric crystals and stretched molecular segments surprisingly makes films less than 80 nm thick yields the record dielectric constant of 84 at room temperature. As the self-regulated crystal assembly is precluded, much lower thin-film dielectric constants and higher dissipation factors are yielded instead, although similar crystallinity and alignment of dipolar polarization have been attained. The persistent stretching of molecular segments related to unveiled crystal self-organization is thus understood as a new direction to create superior directional dipolar polarization, and thus to substantially improve dielectric properties of polymer materials.

The utilization of inorganic ferroelectric ceramics is thought to be an effective approach to enhance output performances of triboelectric nanogenerators (TENGs). However, the large remnant polarization from ferroelectric ceramics traps partial charges on electrodes all the time, which limits the performance improvement of TENGs and their applications in energy harvesting and self-powered sensing. Herein, achieving absolute exploitation of dielectric polarization from inorganic ceramics for significant performance enhancement is unprecedentedly proposed by using antiferroelectric ceramics with large polarization difference. The features of nearly zero remnant polarization and large maximum polarization for antiferroelectric ceramics perfectly match the working cycle mechanism of TENGs, enabling all polarization induced charges to flow through the external circuit. Based on this concept, an ideal flexible Pb0.94La0.04Zr0.98Ti0.02O3 (PLZT) antiferroelectric ceramic inner-layer with record-high polarization difference is developed and assembled into a triboelectric nanogenerator (PLZT-TENG). The PLZT-TENG exhibits an outstanding output of 13.5 nC cm–2, a 1.6-fold enhancement compared with the TENG with a PbZr0.52Ti0.48O3 (PZT) ferroelectric ceramic inner-layer. Thanks to excellent flexibility, stability, and durability, the PLZT-TENG can serve as a biomechanical energy harvester and a self-powered sensor to be applied in practice. Our findings open a generic and upgradable way to the evolution and optimization of TENGs.

Coal-based porous materials for supercapacitors were successfully prepared using Taixi anthracite (TXA) by multi-stage activation. The characterization and electrochemical tests of activated carbons (ACs) prepared in different stages demonstrated that the AC from the third-stage activation (ACIII) shows good porous structures and excellent electrochemical performances. ACIII exhibited a fine specific capacitance of 199 F g&minus, 1 at a current density of 1 A g&minus, 1 in the three-electrode system, with 6 mol L&minus, 1 KOH as the electrolyte. The specific capacitance of ACIII remained 190 F g&minus, 1 even despite increasing the current density to 5 A g&minus, 1, indicating a good rate of electrochemical performance. Moreover, its specific capacitance remained at 98.1% of the initial value after 5000 galvanostatic charge-discharge (GCD) cycle tests at a current density of 1 A g&minus, 1, suggesting that the ACIII has excellent cycle performance as electrode materials for supercapacitors. This study provides a promising approach for fabricating high performance electrode materials from high-rank coals, which could facilitate efficient and clean utilization of high-rank coals.

Detection of characteristic species released from over-heated PVC cables may enable early warning of electrical fires. This work identified the major volatile species for over-heated PVC cables, and verified their potential as fire signatures with metal oxide gas sensors. Semi-volatile Dioctyl phthalate (DOP) and 2-Ethylhexanol (2-EH) were found to be ubiquitously present in the cable vapors as major species. Detection of these species and the vapors of overheated cables was accomplished with a metal oxide gas sensor. The response of the gas sensor to the cable vapors resulted mainly from DOP and 2-EH, demonstrating them as effective signature gases for over-heated PVC cables. A gas sensor based on SnO2 nanofibers was prepared with greatly enhanced response to the signature gases. Large-scale simulation tests showed that the nanofiber gas sensor could effectively detect the cable overheating at an early stage.

With the rapid increase in population density in urban cities, it is inevitable that vibrations levels due to myriad of reasons will be higher. Coupled with increased risk of terrorism, there is a need to mitigate ground vibrations caused by man-made ground shock from possible acts of terrorism. One of the most effective ways of reducing ground vibration caused by man-made activities is to introduce a seismic wave barrier between the source and the area of interest. Besides hardening an underground structure, it is possible to use a seismic wave barrier to mitigate ground shock pressure on the structure. The objective of this research is to study the responses of sand-rubber mixtures (SRM) as a seismic wave barrier to vibration and ground shock. Characterisation of SRM using laboratory tests were performed. Two separate series of small-scale field tests were performed. The first series involves using SRMs and open trench as seismic wave barrier against surface waves complemented with numerical simulations using LS-DYNA. Dimensionless amplitude ratio (Ar) contour plots were developed for use as a preliminary guide in implementation of seismic wave barrier on site. The second series involves using SRM to protect underground structure against ground shock caused by buried explosions. The field tests were modelled in LS-DYNA. The finite element model in LS-DYNA was verified to be able to correctly simulate underground explosions. The finite element model was able to replicate the field test results. In additions, the effect of density ratio between soil and structure on the peak incident pressure was examined through numerical modelling. Doctor of Philosophy

Core-shell microspheres have been applied in various research areas and, in particular, they are used in the generation of photonic nanojets with suitable design for photonic applications. The photonic nanojet is a narrow and focused high-intensity light beam emitting from the shadow-side of microspheres with tunable effective length, thus enabling its applications in biosensing technology. In this paper, we numerically studied the photonic nanojets brought about from biocompatible hydrogel core-shell microspheres with different optical properties. It was found that the presence of the shell layer can significantly affect the characteristics of the photonic nanojets, such as the focal distance, intensity, effective length, and focal size. Generally speaking, the larger the core-shell microspheres, the longer the focal distance, the stronger the intensity, the longer the effective length, and the larger the focal size of the generated photonic nanojets are. The numerical simulations of the photonic nanojets from the biocompatible core-shell microspheres on a Klarite substrate, which is a classical surface-enhancing Raman scattering substrate, showed that the Raman signals in the case of adding the core-shell microspheres in the system can be further enhanced 23 times in water and 108 times in air as compared in the case in which no core-shell microspheres are present. Our study of using tunable photonic nanojets produced from the biocompatible hydrogel core-shell microspheres shows potential in future biosensing applications.

The surface plasmons that are excited by the multiple layer grating structures on the gold thin film are studied using the finite-difference time-domain method in this paper. The structure parameters’ effects on the coupling enhancement of surface plasmons are examined, and the structure design guidelines are given. It is found that the distance between the grating layers and the distance between the gratings and gold thin film are the key structure parameters for better cavity resonances. To have the stronger field enhancements of the excited surface plasmons for the multilayer grating structures, it is found that the width of the gratings should be smaller for the lower grating layers. The multiple layer gratings with proper structure designs can have better performances than single layer grating structure because the cavity effects can enhance the light coupling and more light can be coupled into the surface plasmons by more layers of grating. It is found that the maximum electric field intensity for five layer grating structures can be 163% of the case of the single layer grating structure in our simulations.

Due to the rapid progress in MEMS-based infrared emitters and sensors, strong demand exists for suitable plasmonic materials for such microdevices. We examine the possibility of achieving this goal by alloying other metals with the noble metals Au and Pt, which have some drawbacks, such as low melting point, structural instability, and high costs. The six different metals (Ir, Mo, Ni, Pb, Ta, and W) which possess good properties for heat resistance, stability, and magnetism are mixed with noble metals to improve the properties. The optical properties are calculated by density functional theory and they are used for further investigations of the optical responses of alloy nanorods. The results show that the studied alloy nanorods have wavelength selective properties and can be useful for infrared devices and systems.

This paper presents an inkjet printing and filling process to produce $250\mu \mathrm{m}$ deep Ag-based fully filled through silicon vias with the aspect ratio of via depth vs. diameter up to 5. With the optimization of the printing pattern, humidity control, and silver mirror reaction, the Ag TSV subjected to 400°C thermal anneal for 60 mins can exhibit a resistivity of $26\mu\Omega\bullet \mathrm{cm}$ , the lowest resistivity and highest AR ever reported. Process simplicity and no need of metal liners make the technique with great potential for 3D microsystem integration.

The operating frequency of the plasmonic devices can be tuned by the materials. In this work, we simulate the silver-based bi-metallic alloys and discuss the effects of band shifting on permittivity.

Zn-Sb alloys are potential low-cost and non-toxic p-type thermoelectric materials for applications in the temperature range between 300 and 700 K. In this experiment, Zn-Sb alloy films were prepared by electron beam evaporation through an ion beam assisted deposition (IBAD). Our studies have confirmed that the structural phase, chemical composition, chemical binding, carrier concentration and microstructures of the film can indeed be effectively controlled by the voltage and current of the ion beam. Particularly, the carrier concentration of the film will rise along with the increase of the argon ion beam current. When the ion beam currents are set at 0.2–0.6 A, the carrier concentrations of the films can be controlled at around 1019–1020 cm−3, which fall within the optimal carrier concentration range for Zn-Sb based thermoelectric materials. The temperature dependence of Seebeck coefficient and the electrical conductivity of the films were measured to evaluate their thermoelectric performance. The results indicate that the film with Zn4Sb3 + ZnSb mixed phase will have better thermoelectric properties. A high power factor value of ~1280 μW/m-K2 is obtained in the films assisted by the ion beam current of 0.6 A. Our results demonstrate that the IBAD technique is extraordinary promising to fabricate Zn-Sb films with excellent thermoelectric performance and can be used to produce other potential thermoelectric materials.

Hairpin probes are used to determine electron densities via measuring the shift of the resonant frequency of the probe structure when immersed in a plasma. This manuscript presents new developments in hairpin probe hardware and theory that have enabled measurements in a high electron density plasma, up to approximately 1012 cm−3, corresponding to a plasma frequency of about 9 GHz. Hardware developments include the use of both quarter-wavelength and three-quarter-wavelength partially covered hairpin probes in a transmission mode together with an easily reproducible implementation of the associated microwave electronics using commercial off-the-shelf components. The three-quarter-wavelength structure is operated at its second harmonic with the purpose of measuring higher electron densities. New theory developments for interpreting the probe measurements include the use of a transmission line model to find an accurate relationship between the resonant frequency of the probe and the electron density, including effects of partially covering the probes with epoxy. Measurements are taken in an inductively coupled plasma sustained in argon at pressures below 50 mTorr. Results are compared with Langmuir probe and interferometry measurements.

The silver nanoparticle-decorated suspended graphene was proposed and fabricated to increase the efficiency of surface-enhanced Raman scattering (SERS) mainly by the enhanced electric field resulting from exciting the localized surface plasmon resonance. The morphology of cavity under the graphene was controlled by the thickness of catalyst and the etching time in the metal-assisted chemical etching process (MacEtch). The reflectance and ellipsometric spectra were examined to understand the optical behaviors of silver nanoparticle-decorated suspended graphene as functions of the etching time. For the samples treated with MacEtch, the Raman signals of graphene and p-mercaptoaniline were greatly enhanced due to the plasmonic cavity effect. Moreover, the graphene could increase the Raman intensity of the probed molecules by chemical enhancement. With the optimal etching time of 15 s, the SERS signals reached the maximum that was 13–15 times larger than those without etching. The electric field enhancement pr...

The conventional Eshelby solution based mean-field schemes may dramatically over-estimate the stress in composites consisting of elastoplastic matrix and elastic reinforcement particles. A new and rational approach is presented to determine the Eshelby tensor of elastoplastic medium to solve this problem. We assume that, during an increment of loading in the Eshelby problem for an elastoplastic medium (EPM), the mechanical property is homogeneous, isotropic and incrementally linearized, and introduce a reference elastic medium (REM) with the identical configuration and elastic property of the EPM studied. For a purely traction boundary value problem, the distribution of the stress increment as well as the constrained elastic strain increment in the EPM can be approximated with that in the REM if both of them are subjected to exactly identical traction boundary condition. As the surface traction increment induced by the eigenstrain increment in an ellipsoidal subdomain Ω in the EPM is applied to the REM, the Eshelby tensor of the REM, S e , can be easily derived with the regular procedure of the traditional Eshelby problem. Then, the Eshelby tensor for the EPM can easily be obtained as S= [ ( L e ) -1 :L ] -1 : S e : [ ( L e ) -1 :L ] , where L e and L are the elastic and the tangent elastoplastic moduli of the EPM respectively. The developed Eshelby tensor is embedded in the conventional Mori–Tanaka scheme to predict the responses of particulate composites subjected respectively to tensile, shear, combined biaxial tensile and shear, and cyclic tensile-compressive, and non-proportional tensile and shear loadings. The comparison with the results obtained with the approaches using isotropic approximation of the tangent elastic modulus, and with the reference ones obtained with full-field FE analyses showed satisfactory agreement, demonstrating the validity of the proposed approach. The approach to determine the Eshelby tensor for elastoplastic media has the following distinct advantages: (1) it employs the regular anisotropic tangent modulus and has a unified form in both elastic and elastoplastic cases; (2) it can easily be embedded in the conventional mean-field homogenization schemes (MFHs) and used for the analyses of effective properties of composites subjected to complex loading histories; (3) it possesses high computational efficiency, since the Eshelby tensor can be simply computed using the elastic and elastoplastic properties of composites with no need of time-consuming numerical ellipsoidal integral in each increment.

A high surface area and low reflection textured surface-enhanced Raman scattering (SERS) substrate with plasmonic gold nanodroplets fabricated by wet etching and island lithography was reported in the present study. Specifically, four textured substrates, planar, pyramid, nanopillar, and nanopillar-on-pyramid, were fabricated. The fabricated structures were simulated using the finite-difference time-domain method and the results agreed with the reflection and dark-field scattering measurements. Although the SERS signals varied in different measured regions because of the random nanostructure, the SERS substrates with nanopillar-on-pyramid structure always have the stronger enhancement factor than the SERS substrates with only pyramids or nanopillars. Based on the atomic force microscope and reflection measurements, the nanopillar-on-pyramid structure provided a large surface area and multiple reflections for SERS enhancement, which was about 3 orders of magnitude larger than that of the planar substrate. Our results can be applied to fabricate the inexpensive, large surface area, and high SERS enhancement substrates.

Low output performances and output retention rates in high humid environments represent serious challenges that have interrupted the large-scale application of triboelectric nanogenerators (TENGs) as portable power supplies and self-powered sensors. Existing approaches of tribo-material optimization and device structure design remain limited in solving the problems of low electrical outputs and output retention rates for TENGs. Here, achieving high electrical outputs and output retention rate in a TENG based on a multi-effect inner-layer and a superhydrophobic outer-layer is first proposed by an organic-inorganic composite and simple self-assembly electrospinning. The inner-layer consisting of polyimide (PI) and 0.85Na0.5Bi0.5TiO3-0.15SrTiO3 (NBT-15ST) ceramic particles (CPs) can distinctly enhance the electrical performances of the device by coupling charge storage effect and hysteretic dielectric polarization. Under a maximum instantaneous force of 50 N, the device delivers a voltage of 1020 V and a current density of 32.5 μA cm−2. Meanwhile, the superhydrophobic outer-layer with novel biomimetic multilevel structures endowing the device with a superior output retention rate of 50% at a high relative humidity of 80%. This work provides a new strategy to optimize the electrical outputs of the TENG and extends its application in humid conditions.

Introduction A key to prevent and control fires lies in the early and accurate detection of fire signatures. Over-heated or burned electrical cable with PVC (polyvinyl chloride) insulation or sheath is a frequent cause of fire. PVC cable insulation contains a large amount of various additives like plasticizers, which can be substantially emitted under overheating conditions. Our recent study showed that two widely-used plasticizers, Dioctyl phthalate (DOP) and 2-Ethylhexanol (2-EH), are ubiquitously present in the vapors of different overheated PVC cables, and can be used as a reliable signature of cable overheating [1]. These compounds, especially DOP, have low vapor pressure under normal conditions, and are usually measured through analytical methods like gas-chromatograph mass spectroscopy. These techniques are generally expensive and time-consuming, and thus not suitable for wide applications in fire detection. Metal oxide semiconductor (MOS) gas sensors offer a promising alternative for low-cost and real-time detection of plasticizers. Nevertheless, MOS sensors sensitive and selective to DOP and 2-EH are not yet available. MOS sensors with high gas sensing performance are often made of nanostructured materials based on SnO2, ZnO, etc. Modification of the materials surface by noble metals or metal oxides may efficiently further enhance the sensing performance. In this contribution, we report on the development of gas sensors targeting detection of the fire signature gases and cable overheating, with an emphasis on modified SnO2 hollow nanofibers [2] and ZnO flowers. Results and Conclusions SnO2 nanofibers obtained via electrospinning were porous and hollow, with a diameter of around 200 nm and length of 1-2 mm. They were loaded with various amounts of NiO, In2O3, and ZnO oxides via a facile impregnation-calcination route (Fig. 1). Samples loaded with 2.8 at.% In2O3 (SIn-0.1) and 5.0 at.% ZnO (SZn-0.5) exhibited excellent response to the fire signature gases, DOP and 2-EH, whilst NiO modification deteriorated the sensing performance. A maximum response of 44 and 27 to 100 ppm DOP and 2-EH, respectively, was achieved, ~5 or 9 times larger than that of a commercial TGS822 VOC sensor (Fig. 2). The nanofiber gas sensors exhibited very fast response speed with typical response time of 3-5 s at 260 °C. In contrast, the recovery was much slower, taking ~10 min for DOP. Moreover, low cross-sensitivity towards common interfering gases such as ethanol and H2 were observed. Large-scale simulation tests performed in a 182 L chamber showed that the modified sensors started to respond to the fire hazard earlier than a conventional smoke detector, particularly at lower cable temperatures (below 200 °C), whilst the TGS822 sensor exhibited almost no response (Fig. 3). ZnO flowers fabricated via a hydrothermal route were in a size of a few microns, assembled with nano-columns of ~200 nm diameter. Samples were decorated with various amounts of CuO, Cr2O3, and Au. The modification led to decrease of the operation temperature and enhanced response to the signature gases. The modified ZnO samples presented a maximum response of 48 and 28 to 100 ppm DOP and 2-EH, respectively (Fig. 4). Sensitive response to the cable overheating was also achieved. These results showed that MOS sensors based on modified SnO2 nanofibers and ZnO flowers can effectively detect the overheating of PVC cables, promising for early warning of electrical fires. References [1] J. Han,W. Chen, A. Yu, J. Yi, Detection of semi-volatile plasticizers as a signature of early electrical fire, Frontiers in Materials (2019) 6:250. doi: 10.3389/fmats.2019.00250. [2] J. Yi, W. Chen, J. Han, D. Chen, Sensitive and selective detection of plasticizer vapors with modified-SnO2 hollow nanofibers for electrical fire warning, Sensors & Actuators B. Chemical 287 (2019) 364–370. doi: 10.1016/j.snb.2019.02.025. Figure 1

The utilization of nanoporous materials is an extremely effective approach to enhance the electrical performances of triboelectric nanogenerators (TENGs). However, existing methods for preparing nanoporous tribo-materials not only are complicated, costly and time-consuming but also waste lots of materials. Meanwhile, the fabricated nanoporous tribo-materials with low roughness by nature possess poor surface hydrophobicities, causing low output stability in a humid environment. Here, a bio-inspired petiole-like micron fiber-based tribo-material with inner nanopores, rough surface nanostructures, and superhydrophobicity is first designed by an extraordinarily simple, ultralow-waste and efficient single-component electrospinning. The petiole-like structures and superhydrophobicity endow the assembled triboelectric nanogenerator (PMF-TENG) with outstanding electrical performances and superior output stability under humid conditions. With a giant power density of 56.9 W m–2 and a high peak-to-peak output voltage of 2209 V, the optimized PMF-TENG can not only be used as a biomechanical energy harvester to directly drive 833 light-emitting-diodes and small electronics but also serve as a self-powered sensor to detect body motions. Moreover, under the high relative humidity of 80%, the output retention rate of the optimized PMF-TENG is 1.7 and 2.2 times as high as the TENG assembled with the traditional smoother solid nanofiber-based tribo-material and the monolithic nanoporous tribo-material-based TENG, respectively. This work provides an easy-to-fabricate high-performance nanoporous material-based TENG with ultralow material waste and extends its potential for application in humidity conditions.

The various structure parameters and materials are chosen for artificial cornea. Our simulation results show that increasing the complexity of structures and choosing high refractive index material are important to properties of artificial cornea.