Carbon quantum dots (CQDs) related electrochemiluminescence (ECL) research from 2009 to July 2014 is reviewed. The synthesis, surface states, applications and corresponding reaction mechanism of CQDs ...containing carbon nanodots and graphene quantum dots in ECL studies are comprehensively summarized. Consequently, their research vacancies and the development prospects of these fields are discussed.
•CQDs-based ECL studies from 2009 to July 2014 are reviewed.•CQDs herein contain carbon nanodots and graphene quantum dots.•Synthesis, surface state, application, reaction mechanism of CQDs in ECL are covered.•Research vacancies and development prospects of these fields are discussed.
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•The importance of surface chemistry of graphene materials is clearly described.•We discuss molecularly engineered graphene surfaces for sensing applications.•We describe the latest ...developments of these materials for sensing technology.
Graphene is scientifically and commercially important because of its unique molecular structure which is monoatomic in thickness, rigorously two-dimensional and highly conjugated. Consequently, graphene exhibits exceptional electrical, optical, thermal and mechanical properties. Herein, we critically discuss the surface modification of graphene, the specific advantages that graphene-based materials can provide over other materials in sensor research and their related chemical and electrochemical properties. Furthermore, we describe the latest developments in the use of these materials for sensing technology, including chemical sensors and biosensors and their applications in security, environmental safety and diseases detection and diagnosis.
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Paper-based chips (PB-chips; also referred to as lab-on-paper chips) are using patterned paper as a substrate in a lab-on-a-chip platform. They represent an outstanding technique for fabrication of ...analytical devices for multiplex analyte assays. Typical features include low-cost, portability, disposability and small sample consumption. This review (with 211 refs.) gives a comprehensive and critical insight into current trends in terms of materials and techniques for use in fabrication, modification and detection. Following an introduction into the principles of PB-chips, we discuss features of using paper in lab-on-a-chip devices and the proper choice of paper. We then discuss the versatile methods known for fabrication of PB-chips (ranging from photolithography, plasma treatment, inkjet etching, plotting, to printing including flexographic printing). The modification of PB-chips with micro- and nano-materials possessing superior optical or electronic properties is then reviewed, and the final section covers detection techniques (such as colorimetry, electrochemistry, electrochemiluminescence and chemiluminescence) along with specific (bio)analytical examples. A conclusion and outlook section discusses the challenges and future prospectives in this field.
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This review gives comprehensive and critical insights into the development of materials and techniques for lab-on-paper chips. Its focus is on materials and methods for fabrication, modification and detection.
MXenes are a new family of 2 D transition metal carbides and nitrides, which have attracted enormous attention in electrochemical energy storage, sensing technology, and catalysis owing to their good ...conductivity, high specific surface area, and excellent electrochemical properties. In this work, a series of Co3O4‐doped 3 D MXene/RGO hybrid porous aerogels is designed and prepared through a facile in situ reduction and thermal annealing process, in which the reduced graphene oxide (RGO) conductive network can electrically link the separated Co3O4‐MXene composite nanosheets, leading to enhanced electronic conductivity. It is found that upon using the Co3O4‐MXene/RGO hybrid porous aerogel prepared with a mass ratio of Co3O4‐MXene/RGO of 3:1 (CMR31) as an electrode for a supercapacitor, a superior specific capacitance of 345 F g−1 at the current density of 1 A g−1 is achieved, which is significantly higher than those of Ti3C2Tx MXene, RGO, and MXene/RGO electrodes. In addition, a high capacitance retention (85 % of the initial capacitance after 10 000 cycles at a high current density of 3 A g−1) and a low internal resistance Rs (0.44 Ω) can be achieved. An all‐solid‐state asymmetric supercapacitor (ASC) device is assembled using CMR31, and it has the ability to light up a blue LED indicator for 5 min if four ASCs are connected in series. Therefore, these novel Co3O4‐MXene/RGO hybrid porous aerogels have potential practical applications in high‐energy storage devices.
Porous aerogel electrodes: A Co3O4‐doped 3 D MXene/RGO hybrid porous aerogel (see figure) was synthesized through a facile in situ reduction and thermal annealing process. It shows excellent potential for use in high‐performance all‐solid‐state asymmetric supercapacitors.
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Manganese dioxide (MnO2) with high theoretical capacity (1380 F g−1), high natural abundance and low cost has been considered as one of the most competitive active materials for ...preparing the electrode of supercapacitors. However, the poor electrical conductivity limits its broad applications. To solve this problem, we design a hierarchical Cu(OH)2@MnO2 core-shell nanorods array on copper foam (CF), in which the one-dimensional (1D) Cu(OH)2 nanorod core provides the scaffold for the growth of MnO2 nanosheets and a short ion and electronic diffusion pathway and the two-dimensional (2D) MnO2 nanosheets shell provides enormous active sites due to their large surface area. The obtained Cu(OH)2@MnO2/CF nanorods array displays an excellent areal capacitance of 708.62 mF cm−2 at the current density of 2 mA cm−2 (283.45 F g−1 at 0.8 A g−1). Additionally, the assembled Cu(OH)2@MnO2/CF//activated carbon (AC) asymmetric supercapacitor shows an outstanding energy density of 18.36 Wh kg−1 at a power density of 750 W kg−1. Two such capacitors connected in series can light up a red LED bulb for over fifteen minutes.
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•Nanofibers based on BZT-BCT and P(VDF-TrFE) were successfully prepared through electrospinning method.•The nanofiber generator with 40% contents BZT-BCT exhibits more excellent ...output performance with the Voc of 13.01 V.•The generator is sensitive to the micro force and the Voc performs good linearty within the loading force.•The generator can response to different modes of deformation, even the small movements of human motion.
Recently, the flexible and environmental-friendly piezoelectric generators have drawn much attentions due to the power-supplying apply applications of powering implantable and wearable devices. In this work, an environmental-friendly and flexible piezoelectric nanogenerator is proposed based on electrospinning nanofiber which is composed of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) and polyvinylidene fluoride–trifluoroethylene P(VDF-TrFE). The as-prepared nanofiber mats with different amounts of doping of BZT-BCT nanoparticles varied from 0 wt% to 50 wt% are characterized by XRD and SEM. Based on the testing results, the nanofiber generator with 40 % content of BZT-BCT exhibits the excellent output performance, which produces the output voltage as high as 13.01 V under cyclic tapping under 6 N and 10 Hz, which is mostly attributed from the doping of the BZT-BCT with high piezoelectric coefficient. The generator can be deployed as the self-powered sensor, which can measure the tensile and compressive deformation, the movement of different parts of body. Due to the advantages of flexibility and environmental kindness, this developed nanogenerator has great potential for wearable and implantable devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Here we report the development of a high-performance electrode material composed of Zn and Ni co-substituted Co carbonate hydroxide (ZnNi-Co2(CO3)(OH)2) nanothorns branched on Cu(OH)2 nanorods array ...(Cu(OH)2@ZnNi-Co2(CO3)(OH)2), which are grown directly on copper foam current collector. The electrode materials are obtained by a simple in situ oxidation reaction and a hydrothermal strategy. The as-obtained Cu(OH)2@ZnNi-Co2(CO3)(OH)2 electrode exhibits significantly enhanced electrochemical performance with a high specific capacitance (2746 F g−1 at 1 A g−1), and extraordinary cycling stability (maintained 95.61% of the initial capacitance after 6000 cycles at 20 A g−1), which are much superior to those of Cu(OH)2, Cu(OH)2@ Co2(CO3)(OH)2, Cu(OH)2@Ni-Co2(CO3)(OH)2, and bare ZnNi-Co2(CO3)(OH)2 nanospheres electrodes. Additionally, the Cu(OH)2@ZnNi-Co2(CO3)(OH)2 nanorods array can also be utilized as the positive electrode to fabricate an asymmetric supercapacitor device with an active carbon negative electrode, realizing a high cell voltage of 1.5 V and the energy density of up to 34.75Wh kg−1 at a power density of 375 W kg−1. The excellent electrochemical properties can be credited to the three-dimensional hierarchical core-shell architecture.
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•Hierarchical Cu(OH)2@ZnNi-CoCH nanorods array is fabricated on 3D Cu foams.•The materials are obtained by an oxidation reaction and a hydrothermal strategy.•Cu(OH)2@ZnNi-CoCH electrode exhibits superb supercapacitive performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Utilizing solar energy to evaporate water is an environment-friendly and promising approach for various applications such as seawater desalination. Various photothermal materials can be developed for ...evaporating water, however, there are still some drawbacks such as complicated synthesis processes, weak/narrow absorbance, bulkiness, and low evaporation rate, which severely limit their commercial applications. Herein, we reported the preparation of electrochemically-etched carbon fiber cloth with surface-coated carbonized polyaniline nanowires (ECFC/CPANW) based on thermally-treated pre-oxidized polyacrylonitrile fiber cloth for highly efficient solar steam generation. This ECFC/CPANW composite has the advantages of low thermal conductivity, effective broadband solar absorption, good hydrophilicity and water transfer ability. When ECFC/CPANW and polyurethane foam are bound together as a solar evaporator, ECFC/CPANW achieved the highest vaporization efficiency of up to 93.7% under 1 sun illumination, which is more efficient than those of most materials previously reported. Therefore, this kind of photo-thermal conversion material with low cost, good stability and environmental friendliness could envision promising practical application for water treatment.
Electrochemically etched carbon fiber cloth with surface-coated carbonized polyaniline nanowires (ECFC/CPANW) shows three-dimensional porous structure, low thermal conductivity, high mechanical strength, broadband solar absorption and efficient water supply capacity, resulting in highly efficient solar steam generation performance. Display omitted
•The ECFC/CPANW is designed for solar seawater desalination.•The ECFC/CPANW shows evaporation rates of 1.4255 kg m-2 h-1 under 1 kW m-2 with the evaporation efficiency up to 93.7%.•The ECFC/CPANW exhibits good desalination performance with the ion rejection over 99.9%.
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Flexible wearable sensors have received considerable popularity due to their potential application in monitoring human activities and health conditions. However, traditional pressure sensors always ...rely on a single mechanism (such as piezoelectric or piezoresistive effect), which shows great limitation in the cooperative monitoring of static and highly dynamic pressure detection and severely restricts their further practical applications. Herein, a new strategy of combining piezoelectric and piezoresistive mechanisms in one single flexible sensor is reported for the realization of dual function detection. In detail, a piezoelectric unit (non-array and array) based on a flexible poly(vinylidene fluoride) (PVDF) polymer is deployed for highly dynamic detection, while the composite of graphite sheet (GS)-decorated PVDF electrospun mat composite serves as a piezoresistive unit for static detection. The device exhibits excellent piezoresistive durability (over 600 cycles) and higher piezoelectric sensitivity of 0.5 N V
−1
at the applied frequency of 5 Hz due to the fact that the introduction of a soft piezoresistive layer increases the transverse strain on the piezoelectric layer originating from large deformation of the low stiffness surface. On the basis of the collaborative and complementary advantages, accurate and reliable detection of human motions such as elbow and heel activities are realized, indicating great potential in wearable electronics applications from zero to high frequency. This study provides general guidance for the development of flexible pressure sensors that require dynamic and static cooperative detection capabilities.
A dual-function flexible sensor is prepared by coupling piezoresistive and piezoelectric mechanisms for the simultaneous detection of highly dynamic and static behavior and used to effectively detect body movements, such as elbow and heel motions.
Graphene oxide (GO) was rarely used as microwave absorption (MA) material due to its lower dielectric loss compared with reduced GO (RGO). However, the characteristics of low conductivity, light ...weight, and large surface area were beneficial to the impedance matching for absorbers already containing highly conductive metal materials. Cu@Ni nanowires are promising MA materials due to the desired dielectric loss from copper and excellent magnetic loss from nickel. However, the high density was an impediment to its further application. Combining Cu@Ni nanowires with GO should be an effective solution to decrease the absorber's density and improve its MA properties. Herein, we demonstrated that Cu@Ni nanowires/GO composites exhibited enhanced MA capacities compared with Cu@Ni nanowires or GO alone, and the minimum reflection loss reached -42.8 dB at 16.9 GHz with a thickness of 2.1 mm. The enhanced MA performance mainly originated from good impedance matching, as a result of the addition of low conductivity of GO. To confirm this point, the MA performance of Cu@Ni nanowires/RGO was studied, and unsurprisingly, weak MA performance was obtained. Our work provides a new strategy to decrease the density, broaden the frequency band and tune MA performance of composites.
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