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In this study, the starches were isolated from three botanical sources (i.e., rice, sweet potato, and lotus seed). The size distributions of starch granules and molecules were determined by asymmetrical flow-field flow fractionation (AF4), and compared with those measured from optical microscopy (OM) and dynamic light scattering (DLS). Furthermore, the starches were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). AF4 coupled online with UV–visible, multiangle light scattering (MALS), and differential refractive index (dRI) detectors (AF4-UV-MALS-dRI) was employed for the investigation of the digestion and retrogradation properties of starches. Meanwhile, the relationships between the size of starch at nano- to microscale and its functional properties (i.e., digestibility, retrogradation, and thermal properties) were studied by Pearson correlation analysis. AF4-UV-MALS-dRI was proved to be a rapid and gentle method for the separation and size characterization of starches at both micro- and nano-molecule levels. Moreover, it was demonstrated that AF4-UV-MALS-dRI is a useful tool for the monitoring of the digestion and retrogradation properties of starches. The results suggested that the sizes of starch granules and molecules were to some extent correlated with their thermal properties and digestibility, but not with retrogradation property.

The fabrication of efficient catalysts to reduce nitrogen (N2) to ammonia (NH3) is a significant challenge for artificial N2 fixation under mild conditions. In this work, we demonstrated that the simultaneous introduction of oxygen vacancies (OVs) and Mo dopants into Bi5O7Br nanosheets can significantly increase the activity for photocatalytic N2 fixation. The 1 mol% Mo-doped Bi5O7Br nanosheets exhibited an optimal NH3 generation rate of 122.9 μmol g−1 h−1 and durable stability, which is attributed to their optimized conduction band position, suitable absorption edge, large number of light-switchable OVs, and improved charge carrier separation. This work provides a promising approach to design photocatalysts with light-switchable OVs for N2 reduction to NH3 under mild conditions, highlighting the wide application scope of nanostructured BiOBr-based photocatalysts as effective N2 fixation systems.

Metal halide perovskites are promising semiconductors for next-generation light-emitting diodes (LEDs) due to their high luminance, excellent color purity, and handily tunable band gap. However, it remains a great challenge to develop perovskite LEDs (PeLEDs) with pure red emission at the wavelength of 630 nm. Herein, we report a spectrally stable and efficient pure red PeLED by employing sequential ligand post-treated CsPbI3 quantum dots (QDs). The synthesized CsPbI3 QDs with a size of ∼5 nm are treated in sequential steps using the ligands of 1-hydroxy-3-phenylpropan-2-aminium iodide (HPAI) and tributylsulfonium iodide (TBSI), respectively. The CsPbI3 QD films exhibit improved optoelectronic properties, which enables the fabrication of a pure red PeLED with a peak external quantum efficiency (EQE) of 6.4% and a stable EL emission centered at the wavelength of 630 nm. Our reported sequential ligand post-treatment strategy opens a new route to improve the stability and efficiency of PeLEDs based on QDs.

Morphology transformation and crystal growth strategies of metal oxide semiconductors are extensive studied in material science recently, because the morphology and crystallinity of the nanomaterial have significant effect on the physicochemical characteristics. However, understanding the morphology changes of α-MoO3 induced by annealing temperature is still a challenge. Herein, the nanostructure transition of MoO3 induced by calcined temperature has been investigated through XRD and SEM method. It can be found that crystallization is highly dependent on the annealing temperature. In addition, the MoO3 nanoflowers can change into nanosheets at 500 ºC. Afterwards, the nanosheets turn into microrods, especially at 900 ºC due to the growth of MoO3 crystal. On the other hand, MoO3 is a traditional sensing material, which is sensitive to many volatile organic compounds. Thus, the sensing performances of various MoO3 nanostructures were measured. Compared with MoO3 nanoflowers and microrods. The MoO3 nanosheets based sensor has excellent sensing performance towards ethanol, and the maximum gas response value is 8.06.

Catalytic performance of MoN, WN and WC on hydrogen evolution reaction (HER)were investigated by first-principles calculations, especially considering the effect of strain. From the calculation we can see the catalytic ability has an opposite trend with the adsorption capacity. H coverage was found to affect WN catalytic activity obviously, however has no effect on MoN and WC. Comparing with the experiments, we inferred that although the top site has the strongest potential catalytic ability, the actual catalytic site for HER is hollow1 site. Some specific transition metal doping (Ni > Fe > Mn > W for MoN, Fe > Co for WN, Ni > Co > Fe> Mn for WC) may indirectly improve the HER catalytic performance. It is worth noting that applying a certain strain (e.g. 2.5% tensile strain for MoN, 5% compressive strain for WN, WC) is helpful for improving the HER catalytic performance. Our work is instructive for HER catalyst development in terms of doping and strain.

Due the energy resource comes from solar energy, resulting in a high working temperature, radiation field has a significant influence on the energy storage efficiency of the high temperature solar thermochemistry. In order to promote the solar energy conversion efficiency of solar driven steam methane reforming (SMR), the idea of regulate the radiation field to be in accordance with the energy conversion on-demand is proposed and the biomimetic leaf-type hierarchical porous structure solar thermochemical reactor is introduced, which can regulate the spatial distribution of solar radiation intensity and optimize the temperature field. Combined with thermochemical kinetics and Finite Volume Method (FVM), the numerical calculation model of the SMR reaction in a biomimetic solar thermochemical reactor is established to optimize the temperature field. The effects of different reaction conditions and reactor parameters on steam methane reforming hydrogen production are analyzed. The results show that methane conversion in the biomimetic leaf-type solar thermochemical reactor is increased by 4.5%.

Wearable biopotential sensing devices are essential to long-term and real-time monitoring of human health. Non-contact, capacitive sensing electrodes prevent potential skin irritations, and are thus beneficial for long-term monitoring. Existing capacitive electrodes are either connected to a separate control circuit via external wires or have limited sensing capacitances, which leads to low signal qualities. This study demonstrates a stretchable capacitive sensing device with integrated electrodes and control electronics, with enhanced signal qualities. The electrodes and the control electronics are fabricated on a common fabric substrate for breathability and strain-limiting protection. The stretchable electrodes are based on an island-bridge design with a stretchability as high as ∼ 100%, and an area ratio as high as ∼ 80%. By using a dielectric calcium copper titanate (CCTO) composite as the adhesive layer, the electrode capacitance can be increased, yielding an enhanced signal-to-noise ratio (SNR) in the acquired biopotentials. This device offers a convenient and comfortable approach for long-term non-contact monitoring of biopotential signals.

The oxygen vacancy caused by ultrathin structures would be introduced into the semiconductor photocatalyst to boost its photocatalytic activity. Herein, ultrathin Bi2O3-Bi2WO6 nanosheet composites have been successfully synthesized via a facile hydrothermal method. Compared to pure Bi2WO6 nanosheets, the Bi2O3-Bi2WO6 nanosheet composites possess abundant oxygen vacancies, which was confirmed by the positron annihilation spectra. The ultrathin Bi2O3-Bi2WO6 nanosheet composites exhibited remarkable photocatalytic degradation performance for oxytetracycline compared with that of pure Bi2WO6 nanosheets. The excellent photocatalytic activities of Bi2O3-Bi2WO6 composites could be attributed to the heterojunction structure and the oxygen vacancies caused by ultrathin structures.

Lithium-sulfur (Li−S) batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical energy density and low material cost. However, the conventional ether-based electrolytes of Li−S batteries are extremely flammable and have high solubility of lithium polysulfides (LiPS), resulting in a high safety risk and a poor life cycle. Herein, we report an ether/carbonate co-solvent fluorinated electrolyte with a special solvation sheath of Li+, which can prevent the formation of dissoluble long-chain LiPS of the sulfur cathode, restrict Li dendrite growth at the anode side, and show fire resistance in combustion experiments. As a result, the proposed Li−S batteries with 70 wt% sulfur content in its cathode deliver stable life cycle, low self-discharge ratio, and intrinsic safety. Therefore, the unique passivation characteristics of the designed fluorinated electrolyte break several critical limitations of the traditional “liquid phase”-based Li−S batteries, offering a facile and promising way to develop long-life and high-safety Li−S batteries.

Flexible pressure sensors (FPSs) are widely demanded for accurate pressure sensing on complex surfaces. FPSs using metal nanoparticles (NPs) as the sensing material have high conductivity and good mechanical properties, but poor gauge factor as a trade-off. In this work, a novel design of the AgNP-based FPS is proposed and testified with the help of the electrohydrodynamics-printing technology, so that the gauge factor can be improved from 8 to 286.8, resulting from the localized micro-zone piezoresistance effect. The working principle of the piezoresistive characteristic is discussed, and two methods to further improve and adjust the gauge factor are proposed and experimentally demonstrated.

Owing to their entropy stabilization and multi-principal effect, transition-metal-based high-entropy oxides are attracting extensive attention as an effective family of anode materials for lithium ion batteries (LIBs). Herein, spinel-type (Al0.2CoCrFeMnNi)0.58O4-δ HEO nanocrystalline powder with high concentration of oxygen vacancies is successfully prepared by the method of solution combustion synthesis (SCS), and explored as a novel anode active material for LIBs. As compared to (CoCrFeMnNi)0.6O4-δ, the inactive Al3+-doped (Al0.2CoCrFeMnNi)0.58O4-δ anode provides more than twice the reversible specific capacity of 554 mAh g−1 after 500 cycles at a specific current of 200 mA g−1, accompanied with good rate capability (634 mAh g−1 even at 3 A g−1) and cycling performance. The enhanced electrochemical properties can be attributed to that inactive Al3+-doping resulted into the more space for Li+ intercalation and deintercalation, enhanced structural stability, and the improved electronic conductivity and Li+ diffusivity.

The design and construction of advanced electrode materials is important to the development of high-performance electrochemical energy storage devices. In this paper, V-doped 1T MoS2 nanosheets with a large layer spacing are grown on carbon cloth (CC) via a one-step hydrothermal method. The resulting material features abundant edge sites and active centers, and its large layer spacing facilitates the interlayer shuttle of Na+. Doping with V buffers the volume change and maintains the integrity of MoS2. The layered structure of the composite featuring CC as a conductive substrate effectively prevents the agglomeration of MoS2 during the electrochemical process. When used as an anode material for a Na+ battery, the material displays a high first-cycle irreversible discharge specific capacity of 1234.9 mAh g−1. A specific capacity of 453.2 mAh g−1 is obtained after 100 cycles at a current density of 200 mA g−1. This work provides an effective and eco-friendly route toward obtaining superior MoS2 electrodes for high-performance Na+ storage.

A large soft-cavity host composed of 1,4-diiodotetrafluorobenzene (DITFB) and 4-biphenylpyridine N-oxide (BPNO) is assembled under the mediation of a planar aromatic guest molecule (pyrene or perylene) through C-I⋅⋅⋅- O-N+ halogen bonds and π-hole⋅⋅⋅π bonds. Single-crystal X-ray diffraction reveals that guest molecules can be completely encapsulated in the four-layer host cavity to assemble ternary host-guest cocrystals; namely, Pyr@DITFB ⋅ BPNO and Per@DITFB ⋅ BPNO. The luminescence of these ternary cocrystals originates from their discrete guest molecules, which exhibit pure-blue and yellow emissions, respectively, that are localized at 425 nm and in the range of 485 to 578 nm, respectively. In addition, the contribution of different fragments to the stabilization of the crystal structure is estimated by computational chemistry. These cocrystals have significant potential for use in optical applications or materials, such as photonics or organic light-emitting diodes, respectively, that require to avoid the aggregation between luminophores.

In infrared detection system on aircrafts, the infrared window, as an essential part, always faces heating condition generated by aerodynamic effects. The accurate thermal analysis can ensure the safety and reliability of internal detection system. In this work, the transient thermal characteristics of infrared window-based encapsulation structure are investigated under a high heat flux loading. The physical model of coupled radiative-conductive heat transfer in the window is established while the spectral selectivity of the window to thermal radiation is considered. The transient temperature response is used to evaluate the thermal characteristics. The effect of the radiative heat transfer is firstly analyzed and compared with the pure heat conduction model. There is a temperature deviation (74.1 K) when the radiative heat transfer is ignored. Subsequently, the transient temperature response is simulated under three different kinds of heat flux respectively. It is found that the effect of external heat flux loading is significant. The highest temperature difference reaches 32.9% (299 K) when the heat flux is reduced by 0.5 times and achieves 86.3% (794 K) when the heat flux is increased by 2.5 times. Moreover, the geometric dimensions of window (shape of a truncated cone) generate an effect on its heat transfer characteristics. The temperature decreases significantly (37.8%) when the thickness rises from 10 mm to 20 mm (r = 25 mm) while the temperature decreases relatively small (8.1%) when the radius increases from 15 mm to 45 mm (d = 15 mm). The results reveal that the radiative heat transfer in the window should be carefully considered, especially under the high heat flux loading. Additionally, reducing heat flux or thickening window can improve insulation effectiveness so as to ensure the stable working of the internal equipment.

All-inorganic cesium lead halide perovskite colloidal nanocrystals are attractive for next-generation light-emitting diodes because of their high color purity, but the nonradiative Auger recombination in perovskite nanocrystal film limits the efficiency and brightness of the fabricated devices. Here, we introduce a surface-engineering process to exchange the original long-chain oleic acid/oleylamine ligands by the cerium-tributylphosphine oxide hybrid ligands to suppress nonradiative Auger recombination in CsPbBr3 NC film for bright and low-efficiency roll-off light-emitting diodes. Using ultrafast transient absorption and time-resolved photoluminescence spectroscopy, we demonstrate that the hybrid ligand passivation can efficiently remove surface trap states to enhance radiative recombination and homogenize the exciton concentration to suppress nonradiative Auger recombination in the CsPbBr3 nanocrystal thin film. Consequently, we fabricate a light-emitting diode with efficient charge injection into the CsPbBr3 nanocrystal emitting layer, achieving a pronounced improvement of electroluminescence with an external quantum efficiency from 5.5% to 9.1%. More importantly, the efficiency roll-off characteristics of high-brightness light-emitting diodes is effectively mitigated. Our reported hybrid ligand passivation suppressed Auger recombination strategy shows a great potential for fabricating high-brightness cesium lead halide perovskite light-emitting diodes.

The creation of drag-reducing surfaces in deformed tubes is of vital importance to thermal management, energy, and environmental applications. However, it remains a great challenge to tailor the surface structure and wettability inside the deformed tubes of slim and complicated feature. Here, we describe an electrochemical anodization strategy to achieve uniform and superhydrophobic coating of TiO2 nanotube arrays throughout the inner surface in deformed/bend titanium tubes. Guided by a hybrid carbon fibre cathode, conformal electric field can be generated to adaptatively fit the complex geometries in the deformed tube, where the structural design with rigid insulating beads can self-stabilize the hybrid cathode at the coaxial position of the tube with the electrolyte flow. As a result, we obtain a superhydrophobic coating with a water contact angle of 157° and contact angle hysteresis of less than 10°. Substantial drag reduction can be realised with an overall reduction up to 25.8 % for the anodized U-shaped tube. Furthermore, we demonstrate to spatially coat tubes with complex geometries, to achieve energy-saving liquid transportation. This facile coating strategy has great implications in liquid transport processes with the user-friendly approach to engineer surface regardless of the deformation of tube/pipe.

With the emergence of antibiotic resistance, the development of efficient antimicrobial agents has become increasingly important. Graphene oxide (GO) has been used as an antibacterial agent, but how to realize and improve the antibacterial properties of GO is still required critically. Herein, we prepared two GO samples, abbreviated as GO-V11 and GO-V9. Positron annihilation spectra showed that they possessed predominantly

In this article, three-dimensional nanoporous Cu/Cu6Sn5 microparticles (3D-NP Cu/Cu6Sn5 MPs) were prepared by one-step chemical dealloying of Cu20Sn80 (at%) alloy slices in a mixed aqueous solution of HF and HNO3 and then filled into a three-dimensional porous copper foam (3D-PCF) skeleton as anode (3D-PCF@Cu/Cu6Sn5) for lithium-ion batteries (LIBs). The results show that the ellipsoidal 3D-NP Cu/Cu6Sn5 MPs with feature sizes of 3 to 8 μm are composed of numerous uniform nanoparticles (100 to 200 nm) and plenty of voids. Compared with similar Sn-based electrodes in this work and other published reports, the as-prepared electrode delivers more outstanding electrochemical performance with a superior reversible capacity of 1.90 mAh cm−2, 84.44% capacity retention and > 99.5% coulombic efficiency upon 200 cycles. The cycling stability and integrity of the overall structure of the composite electrode have been greatly enhanced under the synergistic effect of the buffer effect of copper as the inactive component, the unique hierarchical porous electrode architecture and the effective limitation in three dimensions of the 3D-PCF skeleton. We are confident that this work can provide new-generation LIBs with a promising anode candidate and a facile method of dealloying, and a subsequent filling step can achieve the practical production and application of high-performance LIBs.

Ga-doped ZnO (GZO) thin-film transistors (TFTs) with different doping concentrations ( ${n}_{Ga}$ : ${n}_{Zn} =0$ , 1:150, 1:75, 1:50) were successfully fabricated by atomic layer deposition. Among them, GZO TFTs with the doping concentration of 1:75 exhibited a high field-effect mobility of 16.2 cm2 V−1 s−1, a small subthreshold swing of 0.22 V dec−1, a high ON-/ OFF-current ratio of 107, and a proper threshold voltage of 6.0 V as well as a small threshold voltage shift of 0.14 V under positive bias stress. Compared to ZnO (ZO) TFTs, GZO TFTs exhibit excellent bias stability and electrical properties, which can be attributed to appropriate Ga doping concentration suppressing the oxygen vacancy defects, decreasing the trap density at the Al2O3/ZO interfaces, and broadening energy band of the ZO thin films.

The central nervous system (CNS) injury has been a worldwide clinical problem for regenerative medicine. Nerve tissue engineering is a new strategy for CNS injury. Among kinds of biomaterials, graphene oxide (GO)-based degradable composite materials are considered to be promising in the field of neurogenesis. In this study, GO and L-theanine (TH) were combined by chemical grafting to prepare a new PLGA/GO-TH composite material. X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier-transform infrared spectra (FTIR), contact angle testers, and mechanical testers were performed to obtain characterization of composite materials. The protein adsorption efficiency of the PLGA/GO-TH films was then evaluated. Next, the effect of the composite films on neural stem cell (NSC) survival, proliferation, and differentiation was investigated. Our results indicated that L-theanine was successfully grafted onto GO. PLGA/GO-TH composite film can significantly improve NSC survival, proliferation, and neuronal differentiation. Our results demonstrated that the neurogenesis function of a novel PLGA/GO-TH composite film and its potential as a carrier for the further application in the CNS injury.

In this work, one three-dimensional periodic composite structure consisting of alumina frame and inscribed nickel spheres is proposed for designing the micron composite porous structure. The finite...

Hierarchically porous structures are a new type of biomimetic structures that have important applications in several fields. In this study, we aimed to put forward and introduce a new type ordered hierarchical porous structure in the design of solar thermal chemical reaction chambers to utilize CH4 and CO2. The model of the chambers was established based on the hierarchically porous structure. The effect of hierarchically porous structures on the methane reforming performance of a solar thermal chemical reaction chamber was studied. Based on the finite volume method, FLUENT software was combined with user-defined functions to calculate the effect of different pore size combinations and distributions on the methane conversion. The hierarchically porous structure was found to increase the methane conversion because of the excellent flow characteristics and radiation properties of the structure. The different pore size combinations of the hierarchically porous structure were analyzed, and the optimal pore size combination that results in the maximum methane conversion was obtained. Similarly, the different pore size distributions of the hierarchically porous structure were analyzed, and the optimal pore size distribution was obtained. The conversion of methane is the highest when the length of the small hole section is 0.02 m. This study can provide a new process and reference for the utilization of CH4 and CO2 and design of solar high-temperature thermochemical reaction chambers, based on the hierarchically porous structure. The maximum methane conversion of approximately 85% was found at d1 = 1.0 mm, d2 = 2.5 mm, and L1 = 0.02 m.

The purpose of this study was to explore the application of graphene-based nanocomposites in electrochemical detection of heavy metal ions. In this study, Graphene oxide (GO) was synthesized with improved Hummers method, and flower-like MoS2/rGO nanocomposite was synthesized with hydrothermal method and used as electrode modification material. In addition, scanning electron microscopy (SEM) and X-ray images were used to observe the characterization of the prepared samples and to detect the sensitivity of four heavy metal ions under optimal experimental conditions. The results showed that the reduced graphene oxides were coated with a large number of flower-like MoS2 and laid on the reduced graphene oxides. And in electrochemical experiments, adsorption experiments and interference tests, MoS2/rGO nanocomposites showed satisfactory performance for Pb(II). Therefore, this study provided a new strategy for the development of new nanocomposites composites as electrochemical sensors to detect the heavy metal ions in the aquatic environment.

An AlGaN-based deep ultraviolet laser diode with convex quantum wells structure is proposed. The advantage of using a convex quantum wells structure is that the radiation recombination is significantly improved. The improvement is attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes, which results in an increased hole injection efficiency and a decreased electron leakage into the p-type region. Particularly, comparisons with the convex quantum barriers structure and the reference structure show that the convex quantum wells structure has the best performance in all respects.

In this work, we initially synthesized Sb2S3 with uniform flower-like structures via a facile hydrothermal method through the modification of the Sb source and pH value. Afterward, Sb2S3 with a nanosheet structure was successfully synthesized on reduced graphene oxide (Sb2S3@RGO). The flower-like Sb2S3 and the Sb2S3@RGO nanosheets were tested as the counter electrode (CE) of dye-sensitized solar cells, and the latter exhibited a higher electrocatalytic property than the former owing to the introduction of graphene. The results from electrochemical tests indicated that the as-prepared Sb2S3@RGO nanosheets possess higher catalytic activity, charge-transfer ability, and electrochemical stability than Sb2S3, RGO, and Pt CEs. More notably, the power conversion efficiency of Sb2S3@RGO reached 8.17%, which was higher than that of the standard Pt CE (7.75%).

LAGP (Li1.5Al0.5Ge0.5P3O12) is a promising solid-state electrolyte (SSE) for all solid-state lithium-ion batteries (ASS-LIBs) with its favorable lithium ionic conductivity and good performance on inhibiting lithium dendrite. However, the ultrahigh interfacial resistance between lithium metal anode and LAGP SSEs greatly hinders its application. In this work, a thin film of metallic Bi was sputtered on LAGP to improve the chemical/physical properties of the Li/SSE interface. It is found that the Bi buffer not only inhibits the unfavorable reaction between LAGP SSEs and Li metal, but also improved their compatibility. As a result, the Li/LAGP interfacial resistance was effectively reduced from 2255.6 to 92.8 Ω cm2 at 30 °C. Furthermore, a good performance solid state full cell with a LiFePO4 cathode had been demonstrated. This work provides an effective avenue to address the interfacial challenges between Li metal and LAGP SSE.

This work demonstrates a novel design of thin film transistors composed of a bilayer structure of ZnO thin films (O3 as oxidant/H2O as oxidant) prepared by atomic layer deposition. Based on this structure, a large ION/IOFF ratio of 108 at VDS = 0.1 V, a high field-effect mobility of 31.1 ± 0.26 cm2 V−1 s−1, a low threshold voltage of 0.14 ± 0.07 V and a proper subthreshold swing of 0.21 ± 0.02 V/decade as well as an excellent positive bias stress stability have been obtained. The improved performance of the bilayer structured devices is attributed to the first channel layer of ZnO (H2O as oxidant) decreasing the interfacial trap density and providing high mobility, and the second channel layer of ZnO (O3 as oxidant) suppressing the off-state current as well as a newly formed sub-channel at the interface between the two channel layers.

Two-dimensional (2D) semiconductors have the potential to revolutionize future electronics. However, large Schottky barriers exist between 2D semiconductors and metals due to the Fermi level pinning effect, which seriously limits their applications. Here, we demonstrate ohmic contacts to MoS2 by utilizing transparent ZnO:Al (AZO) conductors without forming any contact barriers. Benefiting from the creation of a van der Waals junction in which the atomic precursors react with the physically adsorbed H2O on the MoS2 surface, a nondestructive interface between AZO and MoS2 can be made without any interfacial chemical interactions and disorder. An ideal AZO–MoS2 ohmic junction, which overcomes the Schottky–Mott limit, is achieved by work function matching for the first time. More importantly, this ideal ohmic junction, to our knowledge, yields so far the highest mobility (26.9 cm2 V−1 s−1), fastest switching speed (0.07 V dec−1) and largest optical average transmittance (nearly 90% throughout the visible range) for monolayer MoS2 (grown by chemical vapor deposition) transistors. Thus, our study not only experimentally validates an ideal metal–semiconductor ohmic contact, but also provides a novel material integration method to fabricate high-performance transparent 2D electronic devices.

Efficient dinitrogen (N2) utilization using nitrogen-containing compounds such as ammonia (NH3) and nitrates, which are essential materials for modern fertilizers, medicines, etc., is important to the development of human society. However, the industrial synthesis of NH3 and nitrates requires high temperatures and pressures along with massive energy consumption. In this context, photocatalytic N2 fixation is regarded as an alternative promising strategy for the synthesis of nitrogen-containing compounds under ambient conditions. In this minireview, fundamental photocatalytic N2 fixation mechanisms, including N2 photoreduction to NH3 and photooxidation to nitrates, are initially elaborated. Then, we focus on the effects of surface defect engineering (e.g., surface vacancies and heteroatom dopants) over semiconductor-based photocatalysts for efficient N2 fixation. Finally, we cast a personal perspective on the possible future challenges faced by defect-containing photocatalysts for N2 fixation. We hope that this minireview can shed light on the further development of rational designs of defect-containing photocatalysts toward efficient N2 fixation into diverse value-added chemical feedstocks.

In recent years, some natural and synthetic non-conjugated luminescence systems have attracted much attention. However, the phosphorescence properties of these materials are generally not very satisfactory due to the lack of special molecular design. In this work, phosphoramidic acid is introduced into the oligomer matrix to construct a non-conjugated photoluminescence system with ultralong phosphorescence lifetimes up to 376.5 and 776.9 ms and high phosphorescence quantum yield (4.6–10.5%). At the same time, the new system also displays good thermo-processing properties, vitreous solid and optical waveguide behavior.

The strategy of controlling the rotation of molecular rotors by hydrogen bonding in the excited state to construct stimuli-responsive luminescent materials (SRLMs) has been proposed. Two bithiophene-dicarbaldehyde rotors, 2T3C and 2T5C, are synthesized to confirm this strategy. The conformational changes of the bithiophene-dicarbaldehyde rotors in the excited state are discussed through experiments and theoretical calculations. The rotational barrier of 2T3C can be overcome by intermolecular hydrogen bonding, which makes the conformation in the excited state makes to tend to a coplanar conformation. Obvious responses of 2T3C to hydrogen bond donors can be observed in both solid and solution states. After being ground with silica gel in the solid state, the fluorescence changes from a white dark state to a green bright state. Based on the above principle, a smart erasable writing film responding reversibly to the stimulation of water is prepared by doping 2T3C into a PVP polymer matrix.

A full-cellulose derived hydrogel, composed of carboxymethyl cellulose (CMC) and nanofibrillated cellulose (NFC), was successfully manufactured and immobilized with Pd/Fe bimetallic nanoparticles for the dechlorination of 2,4,6-trichlorophenol. The NFC-reinforced CMC hydrogels with or without loading of bimetallic nanoparticles were characterized by Fourier transform infrared spectroscopy, Transmission electron microscopy, Scanning electron microscopy-energy dispersive X-ray, and X-ray diffraction analyses. The effect of amounts of NFC on the loading capacity of Pd/Fe, mechanical properties and specific Brunauer-Emmett-Teller surface areas of NFC-reinforced CMC hydrogel was also investigated. The experimental results showed that Pd/Fe bimetallic nanoparticles were dispersed and fixed in the hydrogel matrix with the nanosize spherical shape. The hydrogel would protect the Pd/Fe nanoparticles from oxidation, and thus providing long-term stability in comparison with only NFC-coated Pd/Fe nanoparticles. The hydrogel loaded with Pd/Fe nanoparticles, as a soft material catalytic system, was investigated to dechlorinate 2,4,6-trichlorophenol and was found to be very effective.

Terahertz (THz) devices, including the THz broadband absorbers, have attracted much attention in the recent decade. However, due to the micron-level precision requirement, the mainstream fabrication technology for THz devices still rely on complex and expensive photolithography or nanoimprinting techniques. Electrohydrodynamics (EHD) printing technology offers a novel, convenient, and cost-effective solution to this issue. A broadband THz absorber with over 90% absorption in the range of 98–353 GHz was designed and fabricated by EHD printing technology, and the inductive fishnet grid structure was used for the metasurface. The equivalent circuit model of the absorber was established based on the transmission line theory and impedance matching theory. Simulation results matched well with the theoretical and experimental results, and further demonstrated that the absorbers were polarization insensitive. Furthermore, both simulation and experiments proved that the absorption spectrum was insensitive to the fishnet grid linewidth and surface resistance, i.e., the design has high tolerance to possible fabrication errors. Therefore, the EHD printing technology can be a promising fabrication method of THz absorbers for future mass production.

Description, Instant interfacial self-assembly of nanoparticle monolayer advances the thin film technology in a “lift-on” and conformal manner., Thin film fabrication is of great importance in modern engineering. Here, we propose a universal and conformal thin film technique enabled by the wetting empowered interfacial self-assembly. By tailoring the contact angle of nanoparticle (NP), a NP monolayer can be assembled instantly (within 5 seconds) with an excellent harvesting efficiency (up to 97.5 weight %). This self-assembly strategy presents a universal applicability on various materials, e.g., nonmetal, metal, and core-shell structures, and can achieve a monolayer with same in-plane area as a 95 cm2 wafer in a single process, indicating great potential for scale-up manufacturing. Through a template transfer, we coat the surface of different substrates (plastic, paper, etc.) with the assembled film in a conformal and nondestructive “lift-on” manner and subsequently demonstrate fluorescent micropatterns. This self-assembly strategy has great implications in advancing thin film technology in a user-friendly and cost-effective fashion for applications in anti-counterfeiting, actuators, and wearable/flexible electronics.

Charge transfer (CT) dynamics across metal-molecule interfaces has important implications for performance and function of molecular electronic devices. CT times, on the order of femtoseconds, can be precisely measured using synchrotron-based core-hole clock (CHC) spectroscopy, but little is known about the impact on CT times of the metal work function and the bond dipole created by metals and the anchoring group. To address this, here we measure CT dynamics across self-assembled monolayers bound by thiolate anchoring groups to Ag, Au, and Pt. The molecules have a terminal ferrocene (Fc) group connected by varying numbers of methylene units to a diphenylacetylene (DPA) wire. CT times measured using CHC with resonant photoemission spectroscopy (RPES) show that conjugated DPA wires conduct electricity faster than aliphatic carbon wires of a similar length. Shorter methylene connectors exhibit increased conjugation between Fc and DPA, facilitating CT by providing greater orbital mixing. We find nearly 10-fold increase in the CT time on Pt compared to Ag due to a larger bond dipole generated by partial electron transfer from the metal-sulfur bond to the carbon-sulfur bond, which creates an electrostatic field that impedes CT from the molecules. By fitting the RPES signal, we distinguish electrons coming from the Fe center and from cyclopentadienyl (Cp) rings. The latter shows faster CT rates because of the delocalized Cp orbitals. Our study demonstrates the fine tuning of CT rates across junctions by careful engineering of several parts of the molecule and the molecule-metal interface.

Autonomous shape transformation is key in developing high-performance soft robotics technology; the search for pronounced actuation mechanisms is an ongoing mission. Here, we present the programmable shape morphing of a three-dimensional (3D) curved gel structure by harnessing multimode mechanical instabilities during free swelling. First of all, the coupling of buckling and creasing occurs at the dedicated region of the gel structure, which is attributed to the edge and surface instabilities resulted from structure-defined spatial nonuniformity of swelling. The subsequent developments of post-buckling morphologies and crease patterns collaboratively drive the structural transformation of the gel part from the "open" state to the "closed" state, thus realizing the function of gripping. By utilizing the multi-stimuli-responsive nature of the hydrogel, we recover the swollen gel structure to its initial state, enabling reproducible and cyclic shape evolution. The described soft gel structure capable of shape transformation brings a variety of advantages, such as easy to fabricate, large strain transformation, efficient actuation, and high strength-to-weight ratio, and is anticipated to provide guidance for future applications in soft robotics, flexible electronics, offshore engineering, and healthcare products.

Textile industry is one of the most polluting industries due to the large quantities of dyeing wastewater it generates and discharges. Herein, we report an eco-friendly and sustainable circular coloration technology based on cationic polyelectrolyte complex to realise salt-free, zero-effluent-discharge circular dyeing for cotton fabrics with a recyclable dyebath by using a typical cationic polyelectrolyte polyhexamethylene biguanide (PHMB) bonded with anionic dyes. The cotton fabrics were first treated with PHMB and then dyed with three commercial acid dyes. Colour measurements show that the colour strength is controllable by adjustment of concentrations of both PHMB and the dyebath. The dyed fabric samples were found to have good/excellent colour levelness (

Functional blood vessels are crucial to wound healing, and faster vascularization means faster tissue repair to some extent. Increasing numbers of pro-vascularization wound coverings are being developed and studied. Moreover, mechanical properties of the extracellular matrix can guide the behaviour of related cells to some degree. Studies have shown that the mechanical range of 1–7 kPa contributes to the differentiation of stem cells into endothelial cells and thus to the process of wound vascularization. Unfortunately, the regulatory mechanics of vascularizing wound coverings have been poorly studied. Silk fibroin (SF) has attracted much attention because of its good biocompatibility, degradability and adjustable mechanical properties. In this paper, silk scaffolds with mechanical properties of 2 kPa and 5.9 kPa were prepared by adjusting the mechanics of silk scaffolds in terms of freezing temperature and aligned structure. The mechanical properties of the 5.9 kPa aligned silk scaffold (ASS) showed good vascularization ability. By adjusting the intermediate conformation and physical structure of Silk fibroin (SF), the mechanical strength of the silk scaffold could be increased, enabling us to better understand the mechanical regulation mode. At the same time, the aligned structure of the aligned silk scaffold (ASS) promoted the migration and proliferation of cells related to wound repair to a certain extent. By adjusting the mechanical properties and physical structure of the material, an aligned silk scaffold with vascularization function was constructed, providing more possibilities for faster wound repair.

Electronic patches, based on various mechanisms, allow continuous and noninvasive monitoring of biomolecules on the skin surface. However, to date, such devices have been unable to sense biomolecules in deep tissues, which have a stronger and faster correlation with the human physiological status. Here, we demonstrate a photoacoustic patch for three-dimensional (3D) mapping of hemoglobin in deep tissues. This photoacoustic patch integrates an array of ultrasonic transducers and vertical-cavity surface-emitting laser (VCSEL) diodes on a common soft substrate. The high-power VCSEL diodes can generate laser pulses that penetrate >2 cm into human tissues and activate hemoglobin molecules to generate acoustic waves, which can be collected by the transducers for 3D imaging of the hemoglobin with a sub-millimeter spatial resolution. Additionally, the photoacoustic signal amplitude and temperature have a linear relationship, which allows 3D mapping of core temperatures with high accuracy and fast response. The results of 3D core temperature mapping and long-term monitoring in ex-vivo and in-vivo studies are validated by commercial devices. With access to biomolecules in deep tissues, this technology adds unprecedented functions to wearable electronics and thus holds significant implications for various applications in both basic research and clinical practice.

The splash morphology and central jet characteristics of a water droplet impacting a thin water film were investigated for carefully controlled liquid film thicknesses of 120–700 μm using a chromatic confocal displacement sensor. The investigations studied the influences of liquid film thickness, impact velocity and surface characteristics. The coalescence and prompt splash morphologies that included three secondary types were presented in a scatter map based on parameter K and dimensionless film thickness δ. A critical threshold was found between a prompt splash with a delayed splash and a prompt splash without a delayed splash. The results show that the splash morphology is sensitive to the film thickness in this range. The surface characteristics affect the expanding of the crown base by changing the flow drag. Observations of the central jet show that the active central jet breakup depends on the film thickness and the impact velocity.

For the first time, a focal-length tunable intra-ocular lens (IOL) device has been realized by a standard-shaped, homogeneous “one material” system. Different to existing technologies, this poly(N-isopropylacrylamide) gel (PNIPAM) based polyelectrolyte system doesn’t require any additional materials (e.g. metal electrodes, movable mechanical structures) to achieve a controllable lens shape transformation for the focal-length shifting actuation. The designed morphological deformation mechanism employs ionic-strength responsive mechanical buckling via controlled swelling of PNIPAM in phosphate buffered saline (PBS) with similar concentration to human eye liquid. This unique approach will unlock great potential in a wide range of smart ocular applications.