Showing papers in "ACS Applied Materials & Interfaces in 2017"
TL;DR: This mini-review summarizes the current status, opportunities, and future challenges of potassium secondary batteries.
Abstract: Potassium may exhibit advantages over lithium or sodium as a charge carrier in rechargeable batteries. Analogues of Prussian blue can provide millions of cyclic voltammetric cycles in aqueous electrolyte. Potassium intercalation chemistry has recently been demonstrated compatible with both graphite and nongraphitic carbons. In addition to potassium–ion batteries, potassium–O2 (or −air) and potassium–sulfur batteries are emerging. Additionally, aqueous potassium–ion batteries also exhibit high reversibility and long cycling life. Because of potentially low cost, availability of basic materials, and intriguing electrochemical behaviors, this new class of secondary batteries is attracting much attention. This mini-review summarizes the current status, opportunities, and future challenges of potassium secondary batteries.
691 citations
TL;DR: The role of graphene in fabricating flexible gas sensors for the detection of various hazardous gases, including nitrogen dioxide, ammonia, hydrogen, hydrogen sulfide, carbon dioxide, sulfur dioxide, and humidity in wearable technology, is discussed.
Abstract: Wearable electronics is expected to be one of the most active research areas in the next decade; therefore, nanomaterials possessing high carrier mobility, optical transparency, mechanical robustness and flexibility, lightweight, and environmental stability will be in immense demand. Graphene is one of the nanomaterials that fulfill all these requirements, along with other inherently unique properties and convenience to fabricate into different morphological nanostructures, from atomically thin single layers to nanoribbons. Graphene-based materials have also been investigated in sensor technologies, from chemical sensing to detection of cancer biomarkers. The progress of graphene-based flexible gas and chemical sensors in terms of material preparation, sensor fabrication, and their performance are reviewed here. The article provides a brief introduction to graphene-based materials and their potential applications in flexible and stretchable wearable electronic devices. The role of graphene in fabricating ...
525 citations
TL;DR: The Ti3C2Tx sensors successfully measured ethanol, methanol, acetone, and ammonia gas at room temperature and showed a p-type sensing behavior and the limit of detection of acetone gas was theoretically calculated to be about 9.27 ppm, presenting better performance than other 2D material-based sensors.
Abstract: Wearable gas sensors have received lots of attention for diagnostic and monitoring applications, and two-dimensional (2D) materials can provide a promising platform for fabricating gas sensors that can operate at room temperature. In the present study, the room temperature gas-sensing performance of Ti3C2Tx nanosheets was investigated. 2D Ti3C2Tx (MXene) sheets were synthesized by removal of Al atoms from Ti3AlC2 (MAX phases) and were integrated on flexible polyimide platforms with a simple solution casting method. The Ti3C2Tx sensors successfully measured ethanol, methanol, acetone, and ammonia gas at room temperature and showed a p-type sensing behavior. The fabricated sensors showed their highest and lowest response toward ammonia and acetone gas, respectively. The limit of detection of acetone gas was theoretically calculated to be about 9.27 ppm, presenting better performance compared to other 2D material-based sensors. The sensing mechanism was proposed in terms of the interactions between the major...
493 citations
TL;DR: The novel bilayered structure composed of wood and graphene oxide (GO) for highly efficient solar steam generation is introduced and exhibited a solar thermal efficiency of ∼83% under simulated solar excitation at a power density of 12 kW/m2.
Abstract: Solar steam generation is a highly promising technology for harvesting solar energy, desalination and water purification. We introduce a novel bilayered structure composed of wood and graphene oxide (GO) for highly efficient solar steam generation. The GO layer deposited on the microporous wood provides broad optical absorption and high photothermal conversion resulting in rapid increase in the temperature at the liquid surface. On the other hand, wood serves as a thermal insulator to confine the photothermal heat to the evaporative surface and to facilitate the efficient transport of water from the bulk to the photothermally active space. Owing to the tailored bilayer structure and the optimal thermo-optical properties of the individual components, the wood–GO composite structure exhibited a solar thermal efficiency of ∼83% under simulated solar excitation at a power density of 12 kW/m2. The novel composite structure demonstrated here is highly scalable and cost-efficient, making it an attractive materia...
472 citations
TL;DR: The recent progress on the synthesis and fundamental aspects of mixed cation and halide perovskites correlating with device performance, long-term stability, and hysteresis are reviewed.
Abstract: Organic–inorganic halide perovskite materials (e.g., MAPbI3, FAPbI3, etc.; where MA = CH3NH3+, FA = CH(NH2)2+) have been studied intensively for photovoltaic applications. Major concerns for the commercialization of perovskite photovoltaic technology to take off include lead toxicity, long-term stability, hysteresis, and optimal bandgap. Therefore, there is still need for further exploration of alternative candidates. Elemental composition engineering of MAPbI3 and FAPbI3 has been proposed to address the above concerns. Among the best six certified power conversion efficiencies reported by National Renewable Energy Laboratory on perovskite-based solar cells, five are based on mixed perovskites (e.g., MAPbI1–xBrx, FA0.85MA0.15PbI2.55Br0.45, Cs0.1FA0.75MA0.15PbI2.49Br0.51). In this paper, we review the recent progress on the synthesis and fundamental aspects of mixed cation and halide perovskites correlating with device performance, long-term stability, and hysteresis. In the outlook, we outline the future ...
431 citations
TL;DR: It is reported that natural wood can be utilized as an ideal solar absorber after a simple flame treatment and represents a renewable, scalable, low-cost, and robust material for solar steam applications.
Abstract: Solar-enabled steam generation has attracted increasing interest in recent years because of its potential applications in power generation, desalination, and wastewater treatment, among others. Recent studies have reported many strategies for promoting the efficiency of steam generation by employing absorbers based on carbon materials or plasmonic metal nanoparticles with well-defined pores. In this work, we report that natural wood can be utilized as an ideal solar absorber after a simple flame treatment. With ultrahigh solar absorbance (∼99%), low thermal conductivity (0.33 W m-1 K-1), and good hydrophilicity, the flame-treated wood can localize the solar heating at the evaporation surface and enable a solar-thermal efficiency of ∼72% under a solar intensity of 1 kW m-2, and it thus represents a renewable, scalable, low-cost, and robust material for solar steam applications.
430 citations
TL;DR: In vitro and in vivo experiments disclose that Ti3C2-DOX shows enhanced biocompatibility, tumor specific accumulation, and stimuli-responsive drug release behavior and achieve effective cancer cell killing and tumor tissue destruction through photothermal/photodynamic/chemo synergistic therapy.
Abstract: Ti3C2 MXene is a new two-dimensional material exhibiting a variety of novel properties including good photothermal effect, and the capability of Ti3C2 for multimodal tumor therapy is in urgent need of development. Herein, ultrathin Ti3C2 MXene nanosheets (∼100 nm) have been synthesized by supplying additive Al3+ to avoid Al loss and employed as a photothermal/photodynamic agent for cancer therapy. The as-obtained nanosheets exhibit outstanding mass extinction coefficient (28.6 Lg–1 cm–1 at 808 nm), superior photothermal conversion efficiency (∼58.3%), and effective singlet oxygen generation (1O2) upon 808 nm laser irradiation. Based on these Ti3C2 nanosheets, a multifunctional nanoplatform (Ti3C2-DOX) is established via layer-by-layer surface modification with doxorubicin (DOX) and hyaluronic acid (HA). In vitro and in vivo experiments disclose that Ti3C2-DOX shows enhanced biocompatibility, tumor specific accumulation, and stimuli-responsive drug release behavior and achieve effective cancer cell killing...
425 citations
TL;DR: There was an enhancement in the overall water-splitting activity of the NiCo2S4@NiFe LDH heterostructures, with a low voltage of 1.6 V, indicating a dramatic improvement in OER performance.
Abstract: Low-cost and highly efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are intensively investigated for overall water splitting. Herein, we combined experimental research with first-principles calculations based on density functional theory (DFT) to engineer the NiCo2S4@NiFe LDH heterostructure interface for enhancing overall water-splitting activity. The DFT calculations exhibit strong interaction and charge transfer between NiCo2S4 and NiFe LDH, which change the interfacial electronic structure and surface reactivity. The calculated chemisorption free energy of hydroxide (ΔEOH) is reduced from 1.56 eV for pure NiFe LDH to 1.03 eV for the heterostructures, indicating a dramatic improvement in OER performance, while the chemisorption free energy of hydrogen (ΔEH) maintains almost invariable. By the use of the facile hydrothermal method, NiCo2S4 nanotubes, NiFe LDH nanosheets, and NiCo2S4@NiFe LDH heterostructures are prepared on nickel...
421 citations
TL;DR: The results reveal that the overall MAP of coated CNTs strongly depends on the magnetic coating structure, and the structure-property relationship revealed is significant for the design and preparation of CNT-based materials with effective microwave absorption.
Abstract: It is well accepted that the microwave absorption performance (MAP) of carbon nanotubes (CNTs) can be enhanced via coating magnetic nanoparticles on their surfaces. However, it is still unclear if the magnetic coating structure has a significant influence on the microwave absorption behavior. In this work, nano-Fe3O4 compact-coated CNTs (FCCs) and Fe3O4 loose-coated CNTs (FLCs) are prepared using a simple solvothermal method. The MAP of the Fe3O4-coated CNTs is shown to be adjustable via controlling the Fe3O4 nanocoating structure. The results reveal that the overall MAP of coated CNTs strongly depends on the magnetic coating structure. In addition, the FCCs show a much better MAP than the FLCs. It is shown that the microwave absorption difference between the FLCs and FCCs is due to the disparate complementarities between the dielectric loss and the magnetic loss, which are related to the coverage density of Fe3O4 nanoparticles on the surfaces of CNTs. For FCCs, the mass ratio of CNTs to Fe3+ is then opti...
421 citations
TL;DR: This work reviews the recent advances in developing ILs as additives for lubrication with an attempt to correlate among the cationic and anionic structures, oil-solubility, and other relevant physicochemical properties, and lubricating behavior.
Abstract: In pursuit of energy efficiency and durability throughout human history, advances in lubricants have always played important roles. Ionic liquids (ILs) are room-temperature molten salts that possess unique physicochemical properties and have shown great potential in many applications with lubrication as one of the latest. While earlier work (2001–2011) primarily explored the feasibility of using ILs as neat or base lubricants, using ILs as lubricant additives has become the new focal research topic since the breakthrough in ILs’ miscibility in nonpolar hydrocarbon oils in early 2012. This work reviews the recent advances in developing ILs as additives for lubrication with an attempt to correlate among the cationic and anionic structures, oil-solubility, and other relevant physicochemical properties, and lubricating behavior. Effects of the concentration of ILs in lubricants and the compatibility between ILs and other additives in the lubricant formulation on the tribological performance are described foll...
421 citations
TL;DR: This strategy of building synergistic "soft and hard" structures is successful to integrate the decent mechanical properties, reliable self-healing capability, and high sensing sensitivity together for assembling a high-performance, flexible, and wearable strain sensor.
Abstract: Robust, stretchable, and strain-sensitive hydrogels have recently attracted immense research interest because of their potential application in wearable strain sensors. The integration of the synergistic characteristics of decent mechanical properties, reliable self-healing capability, and high sensing sensitivity for fabricating conductive, elastic, self-healing, and strain-sensitive hydrogels is still a great challenge. Inspired by the mechanically excellent and self-healing biological soft tissues with hierarchical network structures, herein, functional network hydrogels are fabricated by the interconnection between a “soft” homogeneous polymer network and a “hard” dynamic ferric (Fe3+) cross-linked cellulose nanocrystals (CNCs–Fe3+) network. Under stress, the dynamic CNCs–Fe3+ coordination bonds act as sacrificial bonds to efficiently dissipate energy, while the homogeneous polymer network leads to a smooth stress-transfer, which enables the hydrogels to achieve unusual mechanical properties, such as ...
TL;DR: The designed nanosensor can be applied for efficient detection of intracellular Fe3+ with excellent biocompatibility and cellular imaging capability, and it holds great promise in biomedical applications.
Abstract: Colorimetric and fluorescent dual mode detection methods have gained much attention in recent years; however, it is still desirable to develop new colorimetric and fluorescent dual mode nanosensors with more simple preparation procedures, low cost, and excellent biocompatibility. Herein, a colorimetric and fluorescent nanosensor based on B, N, S-co-doped carbon dots (BNS-CDs) was synthesized by one-step hydrothermal treatment of 2,5-diaminobenzenesulfonic acid and 4-aminophenylboronic acid hydrochloride. Using this nanosensor, a highly sensitive assay of Fe3+ in the range of 0.3–546 μM with a detection limit of 90 nM was provided by quenching the red emission fluorescence. It is more attractive that Fe3+ can also be visualized by this nanosensor via evident color changes of the solution (from red to blue) under sunlight without the aid of an ultraviolet (UV) lamp. Furthermore, the designed nanosensor can be applied for efficient detection of intracellular Fe3+ with excellent biocompatibility and cellular ...
TL;DR: The excellent adsorption capacity and the response to the magnetic field made this novel material an auspicious candidate for environmental remediation technologies.
Abstract: The combination of magnetic nanoparticles and metal–organic frameworks (MOFs) has demonstrated their prospective for pollutant sequestration. In this work, a magnetic metal–organic framework nanocomposite (Fe3O4@AMCA-MIL53(Al) was prepared and used for the removal of U(VI) and Th(IV) metal ions from aqueous environment. Fe3O4@AMCA-MIL53(Al) nanocomposite was characterized by TGA, FTIR, SEM-EDX, XRD, HRTEM, BET, VSM (vibrating sample magnetometry), and XPS analyses. A batch technique was applied for the removal of the aforesaid metal ions using Fe3O4@AMCA-MIL53(Al) at different operating parameters. The isotherm and kinetic data were accurately described by the Langmuir and pseudo-second-order models. The adsorption capacity was calculated to be 227.3 and 285.7 mg/g for U(VI) and Th(IV), respectively, by fitting the equilibrium data to the Langmuir model. The kinetic studies demonstrated that the equilibrium time was 90 min for each metal ion. Various thermodynamic parameters were evaluated which indicated...
TL;DR: The as-fabricated PCHMs can be promising candidates as highly effective microwave absorbers, and the design philosophy can be extended to other spherical absorbers.
Abstract: In this work, mesoporous carbon hollow microspheres (PCHMs) with designable mesoporous shell and interior void are constructed by a facile in situ stober templating approach and a pyrolysis-etching process. The PCHMs are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, Raman spectroscopy, and nitrogen adsorption and desorption system. A uniform mesoporous shell (pore size 4.7 nm) with a thickness of 55 nm and a cavity size of 345 nm is realized. The composite of paraffin mixed with 20 wt % PCHMs exhibits a minimum reflection coefficient (RCmin) of −84 dB at 8.2 GHz with a sample thickness of 3.9 mm and an effective absorption bandwidth (EAB) of 4.8 GHz below −10 dB (>90% electromagnetic wave is attenuated). Moreover, the composite of phenolic resin mixed with 20 wt % PCHMs exhibits an ultrawide EAB of 8 GHz below −10 dB with a thinner thickness of 2.15 mm. Such excellent electromagnetic wave absorption properties are ascribed to the large carbon...
TL;DR: Benefiting from the excellent electrical conductivity, ultralight porous structure, and effective charge delocalization, the composites deliver remarkable EMI shielding performance with a shielding effectiveness (SE) of 91.9 dB and a specific SE of 3124 dB·cm3/g, both of which are the highest among those reported in the literature for carbon-based polymer composites.
Abstract: Ultralight, high-performance electromagnetic interference (EMI) shielding graphene foam (GF)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composites are developed by drop coating of PEDOT:PSS on cellular-structured, freestanding GFs. To enhance the wettability and the interfacial bonds with PEDOT:PSS, GFs are functionalized with 4-dodecylbenzenesulfonic acid. The GF/PEDOT:PSS composites possess an ultralow density of 18.2 × 10–3 g/cm3 and a high porosity of 98.8%, as well as an enhanced electrical conductivity by almost 4 folds from 11.8 to 43.2 S/cm after the incorporation of the conductive PEDOT:PSS. Benefiting from the excellent electrical conductivity, ultralight porous structure, and effective charge delocalization, the composites deliver remarkable EMI shielding performance with a shielding effectiveness (SE) of 91.9 dB and a specific SE (SSE) of 3124 dB·cm3/g, both of which are the highest among those reported in the literature for carbon-based polymer composites. The excelle...
TL;DR: Among these electroplated anodes, Zn-SDS is the most suitable for aqueous batteries thanks to its low corrosion rate, low dendrite formation, low float current, and high capacity retention after 1000 cycles.
Abstract: Novel zinc anodes are synthesized via electroplating with organic additives in the plating solution. The selected organic additives are cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), polyethylene-glycol (PEG-8000), and thiourea (TU). The synthesized zinc anode materials, namely, Zn-CTAB, Zn-SDS, Zn-PEG, and Zn-TU, are characterized by powder X-ray diffraction and scanning electron microscopy. The results show that each additive produces distinctively different crystallographic orientation and surface texture. The surface electrochemical activity is characterized by linear polarization when the zinc is in contact with the battery’s electrolyte. Tafel fitting on the linear polarization data reveals that the synthetic zinc materials using organic additives all exhibit 6–30 times lower corrosion currents. When using Zn-SDS as the anode in the rechargeable hybrid aqueous battery, the float current decreases as much as 2.5 times. The batteries with Zn-SDS, Zn-PEG, and Zn-TU anodes display ...
TL;DR: This work develops a novel Zn/V2O5 rechargeable aqueous hybrid-ion battery system by using porous V2 O5 as the cathode and metallic zinc as the anode to simultaneously enhance the energy density and cycling stability of aqueously zinc ion-based batteries.
Abstract: Aqueous zinc-ion batteries attract increasing attention due to their low cost, high safety, and potential application in stationary energy storage. However, the simultaneous realization of high cycling stability and high energy density remains a major challenge. To tackle the above-mentioned challenge, we develop a novel Zn/V2O5 rechargeable aqueous hybrid-ion battery system by using porous V2O5 as the cathode and metallic zinc as the anode. The V2O5 cathode delivers a high discharge capacity of 238 mAh g–1 at 50 mA g–1. 80% of the initial discharge capacity can be retained after 2000 cycles at a high current density of 2000 mA g–1. Meanwhile, the application of a “water-in-salt” electrolyte results in the increase of discharge platform from 0.6 to 1.0 V. This work provides an effective strategy to simultaneously enhance the energy density and cycling stability of aqueous zinc ion-based batteries.
TL;DR: This study paves the way for thermally conductive polymer composites used as thermal interface materials for next-generation electronic packaging and 3D integration circuits.
Abstract: In this work, we report a fabrication of epoxy resin/ordered three-dimensional boron nitride (3D-BN) network composites through combination of ice-templating self-assembly and infiltration methods. The polymer composites possess much higher thermal conductivity up to 4.42 W m–1 K–1 at relatively low loading 34 vol % than that of random distribution composites (1.81 W m–1 K–1 for epoxy/random 3D-BN composites, 1.16 W m–1 K–1 for epoxy/random BN composites) and exhibit a high glass transition temperature (178.9–229.2 °C) and dimensional stability (22.7 ppm/K). We attribute the increased thermal conductivity to the unique oriented 3D-BN thermally conducive network, in which the much higher thermal conductivity along the in-plane direction of BN microplatelets is most useful. This study paves the way for thermally conductive polymer composites used as thermal interface materials for next-generation electronic packaging and 3D integration circuits.
TL;DR: This facile, cost-effective strategy will provide a useful guideline to integrate with other modified hydrophilic MOFs to design nanofiltration for water treatment.
Abstract: Metal–organic frameworks (MOFs) are studied for the design of advanced nanocomposite membranes, primarily due to their ultrahigh surface area, regular and highly tunable pore structures, and favorable polymer affinity. However, the development of engineered MOF-based membranes for water treatment lags behind. Here, thin-film nanocomposite (TFN) membranes containing poly(sodium 4-styrenesulfonate) (PSS) modified ZIF-8 (mZIF) in a polyamide (PA) layer were constructed via a facile interfacial polymerization (IP) method. The modified hydrophilic mZIF nanoparticles were evenly dispersed into an aqueous solution comprising piperazine (PIP) monomers, followed by polymerizing with trimesoyl chloride (TMC) to form a composite PA film. FT-IR spectroscopy and XPS analyses confirm the presence of mZIF nanoparticles on the top layer of the membranes. SEM and AFM images evince a retiform morphology of the TFN-mZIF membrane surface, which is intimately linked to the hydrophilicity and adsorption capacity of mZIF nanopa...
TL;DR: It is demonstrated that BUT-15 exhibits an uncompromised performance for the detection of Fe3+ ions in a simulated biological system and shows intense fluorescence in water, which can be solely quenched by trace amounts of Fe 3+ ions.
Abstract: Metal–organic frameworks are a class of attractive materials for fluorescent sensing. Improvement of hydrolytic stability, sensitivity, and selectivity of function is the key to advance application of fluorescent MOFs in aqueous media. In this work, two stable MOFs, [Zr6O4(OH)8(H2O)4(L1)2] (BUT-14) and [Zr6O4(OH)8(H2O)4(L2)2] (BUT-15), were designed and synthesized for the detection of metal ions in water. Two new ligands utilized for construction of the MOFs, namely, 5′,5‴-bis(4-carboxyphenyl)-[1,1′:3′,1″:4″,1‴:3‴,1′′′′-quinquephenyl]-4,4′′′′-dicarboxylate (L1) and 4,4′,4″,4‴-(4,4′-(1,4-phenylene)bis(pyridine-6,4,2-triyl))tetrabenzoate (L2), are structurally similar with the only difference being that the latter is functionalized by pyridine N atoms. The two MOFs are isostructural with a sqc-a topological framework structure, and highly porous with the Brunauer–Emmett–Teller (BET) surface areas of 3595 and 3590 m2 g–1, respectively. Interestingly, they show intense fluorescence in water, which can be sol...
TL;DR: Compared with that of free DOX and DOX-loaded NPs without the folic targeting ligand, the FA-targeted NPs exhibited higher antitumor efficacy in vivo, implying that they are a highly promising potential carrier for cancer treatments.
Abstract: In this study, we introduced a targeting polymer poly(ethylene glycol)–folic acid (PEG–FA) on the surface of polydopamine (PDA)-modified mesoporous silica nanoparticles (MSNs) to develop the novel nanoparticles (NPs) MSNs@PDA–PEG–FA, which were employed as a drug delivery system loaded with doxorubicin (DOX) as a model drug for cervical cancer therapy. The chemical structure and properties of these NPs were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption/desorption, dynamic light scattering-autosizer, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The pH-sensitive PDA coating served as a gatekeeper. The in vitro drug release experiments showed pH-dependent and sustained drug release profiles that could enhance the therapeutic anticancer effect and minimize potential damage to normal cells due to the acidic microenvironment of the tumor. These MSNs@PDA–PEG–FA achieved significantly high targeting efficiency, which was demonstrated...
TL;DR: A flexible supercapacitor device based on ZIF-PPy networks shows an outstanding areal capacitance of 225.8 mF cm-2, which is far above other MOFs-basedsupercapacitors reported up to date, confirming the significance of in situ synthetic chemistry as well as the importance of hybrid materials on the nanoscale.
Abstract: Metal–organic frameworks (MOFs) with high porosity and a regular porous structure have emerged as a promising electrode material for supercapacitors, but their poor electrical conductivity limits their utilization efficiency and capacitive performance. To increase the overall electrical conductivity as well as the efficiency of MOF particles, three-dimensional networked MOFs are developed via using preprepared conductive polypyrrole (PPy) tubes as the support for in situ growth of MOF particles. As a result, the highly conductive PPy tubes that run through the MOF particles not only increase the electron transfer between MOF particles and maintain the high effective porosity of the MOFs but also endow the MOFs with flexibility. Promoted by such elaborately designed MOF–PPy networks, the specific capacitance of MOF particles has been increased from 99.2 F g–1 for pristine zeolitic imidazolate framework (ZIF)-67 to 597.6 F g–1 for ZIF–PPy networks, indicating the importance of the design of the ZIF–PPy cont...
TL;DR: Strain sensing performances of recently reported sensors indicate that the appropriate choice of geometric engineering as well as intrinsically stretchable materials is essential for high-performance strain sensing.
Abstract: Stretchable and flexible sensors attached onto the surface of the human body can perceive external stimuli, thus attracting extensive attention due to their lightweight, low modulus, low cost, high flexibility, and stretchability. Recently, a myriad of efforts have been devoted to improving the performance and functionality of wearable sensors. Herein, this review focuses on recent remarkable advancements in the development of flexible and stretchable sensors. Multifunction of these wearable sensors is realized by incorporating some desired features (e.g., self-healing, self-powering, linearity, and printing). Next, focusing on the characteristics of carbon nanomaterials, nanostructured metal, conductive polymer, or their hybrid composites, two major strategies (e.g., materials that stretch and structures that stretch) and diverse design approaches have been developed to achieve highly flexible and stretchable electrodes. Strain sensing performances of recently reported sensors indicate that the appropria...
TL;DR: The κ-carrageenan/PAAm DN hydrogel exhibited a great strain sensitivity with a gauge factor of 0.63 at the strain of 1000%, and thus, the hydrogels can be used as sensitive strain sensors for applications in robotics and human motion detection.
Abstract: On the basis of the thermoreversible sol–gel transition behavior of κ-carrageenan in water, a double-network (DN) hydrogel has been fabricated by combining an ionically cross-linked κ-carrageenan network with a covalently cross-linked polyacrylamide (PAAm) network. The κ-carrageenan/PAAm DN hydrogel demonstrated an excellent recoverability and significant self-healing capability (even when notched). More importantly, the warm pregel solution of κ-carrageenan/AAm can be used as an ink of a three-dimensional (3D) printer to print complex 3D structures with remarkable mechanical strength after UV exposure. Furthermore, the κ-carrageenan/PAAm DN hydrogel exhibited a great strain sensitivity with a gauge factor of 0.63 at the strain of 1000%, and thus, the hydrogel can be used as sensitive strain sensors for applications in robotics and human motion detection.
TL;DR: Two novel flowerlike NiO hierarchical structures, rose-flower and silk-flower, were synthesized by using a facial hydrothermal method, coupled with subsequent postannealing process to improve microwave absorption performances.
Abstract: In this work, two novel flowerlike NiO hierarchical structures, rose-flower (S1) and silk-flower (S2), were synthesized by using a facial hydrothermal method, coupled with subsequent postannealing process. Structures, morphologies, and magnetic and electromagnetic properties of two NiO structures have been systematically investigated. SEM and TEM results suggested that S1 had a hierarchical rose-flower architecture with diameters in the range of 4–7 μm, whereas S2 exhibited a porous silk-flower architecture with diameters of 0.7–1.0 μm. Electromagnetic performances indicated that the NiO hierarchical structures played a crucial role in determining their dielectric behavior and impedance matching characteristic, which further influenced the microwave attenuation property of absorbers based on them. Due to its hierarchical and porous architectures, S2 had higher microwave absorption performances than S1. The maximum RL value for sample S2 can reach −65.1 dB at 13.9 GHz, while an efficient bandwidth of 3 GHz...
TL;DR: Fluorescence measurements show the two lanthanide metal-organic frameworks can selectively and sensitively detect for Fe3+ ion and nitromethane, which suggests that the two Ln-MOFs are promising bifunctional luminescence sensor materials with sensing metal ions and small organic molecules.
Abstract: Two lanthanide metal–organic frameworks (Ln-MOFs) with similar structures have been synthesized through objective synthesis. The two compounds are both 2-fold interpenetrating 3D frameworks. Topological analyses reveal that complexes 1 and 2 are 6-connected pcu net. In addition, both structures were embedded in uncoordinated nitrogen atoms. As the uncoordinated pyridine groups can be used as functional groups, we tested their sensing ability toward metal ions and small organic molecules. To our delight, fluorescence measurements show the two complexes can selectively and sensitively detect for Fe3+ ion and nitromethane, which suggests that the two Ln-MOFs are promising bifunctional luminescence sensor materials with sensing metal ions and small organic molecules.
TL;DR: A facile route to synthesize carbon dots with red emission due to the doping effect of S and N elements, borrowing from the concept of the semiconductor is developed, demonstrating that the S,N-CDs are a potentially excellent bioimaging component in the theranostic field.
Abstract: It is highly desirable and a great challenge for red light emission of carbon dots under long wavelength excitation Here, we developed a facile route to synthesize carbon dots with red emission due to the doping effect of S and N elements, borrowing from the concept of the semiconductor The maximum emission locates at 594 nm under 560 nm excitation The absolute photoluminescence (PL) quantum yield (QY) is as high as 29% and 22% in ethanol and water, respectively XPS and FTIR spectra illustrated that there exist -SCN and -COOH groups on the surface of the carbon dots They endow the carbon dots with high sensitivity for ion detection of Fe3+ The quenched PL emission of Fe3+-S,N-CDs can be recovered by adding ascorbic acid to release the -COOH and -SCN group due to Fe2+ formation in the presence of ascorbic acid High PL QY of red emission is beneficial to application in bioimaging Doxorubicin was loaded onto carbon dots through π–π stacking to form a theranostic agent When the CD-Dox was injected in
TL;DR: The results demonstrate the necessity of a carefully designed composite microstructure depending on the desired applications of an all-solid-state battery.
Abstract: All-solid-state lithium-ion batteries have the potential to become an important class of next-generation electrochemical energy storage devices. However, for achieving competitive performance, a better understanding of the interfacial processes at the electrodes is necessary for optimized electrode compositions to be developed. In this work, the interfacial processes between the solid electrolyte (Li10GeP2S12) and the electrode materials (In/InLi and LixCoO2) are monitored using impedance spectroscopy and galvanostatic cycling, showing a large resistance contribution and kinetic hindrance at the metal anode. The effect of different fractions of the solid electrolyte in the composite cathodes on the rate performance is tested. The results demonstrate the necessity of a carefully designed composite microstructure depending on the desired applications of an all-solid-state battery. While a relatively low mass fraction of solid electrolyte is sufficient for high energy density, a higher fraction of solid elec...
TL;DR: This research realizes the printing of both SMPs and SMNCs, which present an effective strategy to design 4D active shape-changing architectures with multifunctional properties, which paves the way for the further development of 4D printing, soft robotics, flexible electronics, minimally invasive medicine, etc.
Abstract: Four-dimensional (4D) active shape-changing structures based on shape memory polymers (SMPs) and shape memory nanocomposites (SMNCs) are able to be controlled in both space and time and have attracted increasing attention worldwide. However, conventional processing approaches have restricted the design space of such smart structures. Herein, 4D active shape-changing architectures in custom-defined geometries exhibiting thermally and remotely actuated behaviors are achieved by direct-write printing of ultraviolet (UV) cross-linking poly(lactic acid)-based inks. The results reveal that, by the introduction of a UV cross-linking agent, the printed objects present excellent shape memory behavior, which enables three-dimensional (3D)–one-dimensional (1D)–3D, 3D–two-dimensional (2D)–3D, and 3D–3D–3D configuration transformations. More importantly, the addition of iron oxide successfully integrates 4D shape-changing objects with fast remotely actuated and magnetically guidable properties. This research realizes ...
TL;DR: Thermally responsive liquid crystal elastomers (LCEs) are direct-write printed into 3D structures with a controlled molecular order to enable new generations of soft robotics, implantable medical devices, and consumer products.
Abstract: Three-dimensional structures capable of reversible changes in shape, i.e., four-dimensional-printed structures, may enable new generations of soft robotics, implantable medical devices, and consumer products. Here, thermally responsive liquid crystal elastomers (LCEs) are direct-write printed into 3D structures with a controlled molecular order. Molecular order is locally programmed by controlling the print path used to build the 3D object, and this order controls the stimulus response. Each aligned LCE filament undergoes 40% reversible contraction along the print direction on heating. By printing objects with controlled geometry and stimulus response, magnified shape transformations, for example, volumetric contractions or rapid, repetitive snap-through transitions, are realized.