Thermoelectric characteristics of flexible reduced graphene oxide/silver selenide nanowire composites prepared by a facile vacuum filtration process

The reduced graphene oxide/silver selenide nanowire(rGO/Ag;Se NW)composite powders were fabricated via a wet chemical approach,and then flexible rGO/Ag;Se NW composite film was prepared by a facile vacuum filtration method combined with cold-pressing treatment.A highest power factor of 228.88μW·m;·K;was obtained at 331 K for the cold-pressed rGO/Ag;Se NW composite film with 0.01 wt%r GO.The rGO/Ag;Se NW composite film revealed superior flexibility as the power factor retained 94.62%after bending for 500 times with a bending radius of 4 mm,which might be due to the interwoven network structures of Ag;Se NWs and pliability of r GO as well as nylon membrane.These results demonstrated that the GO/Ag;Se NW composite film has a potential for preparation of flexible thermoelectric devices.

Thick Electrodes of a Self-Assembled MXene Hydrogel Composite for High-Rate Energy Storage

Supercapacitors based on two-dimensional MXene(Ti_(3)C_(2)T_(z))have shown extraordinary performance in ultrathin electrodes with low mass loading,but usually there is a significant reduction in high-rate performance as the thickness increases,caused by increasing ion diffusion limitation.Further limitations include restacking of the nanosheets,which makes it challenging to realize the full potential of these electrode materials.Herein,we demonstrate the design of a vertically aligned MXene hydrogel composite,achieved by thermal-assisted self-assembled gelation,for high-rate energy storage.The highly interconnected MXene network in the hydrogel architecture provides very good electron transport properties,and its vertical ion channel structure facilitates rapid ion transport.The resulting hydrogel electrode show excellent performance in both aqueous and organic electrolytes with respect to high capacitance,stability,and high-rate capability for up to 300μm thick electrodes,which represents a significant step toward practical applications.

Thermoelectric transport in conductive poly(3,4-ethylenedioxythiophene)

Poly(3,4-ethylenedioxythiophene)(PEDOT)has proved its quite competitive thermoelectric properties in flexible electronics with its excellent electrical and mechanical properties.Since the early discovery of PEDOT,considerable experimental progress has been achieved in optimizing and improving the thermoelectric properties as a promising organic thermoelectric material(OTE).Among them,theoretical research has made significant contributions to its development.Here the basic physics of conductive PEDOT are reviewed based on the combination of theory and experiment.The purpose is to provide a new insight into the development of PEDOT,so as to effectively design and preparation of advanced thermoelectric PEDOT material in the future.

Research Article Core/hybrid-shell structures boost thermoelectric performance of flexible inorganic/organic nanowire films

Interface control in inorganic/organic composites has always been regarded as one of the effective means to optimize their thermoelectric(TE)performance,and the past few years have witnessed its development,including carrier-energy filtering and phonon scattering.However,the energy barrier created by the band alignment at the composite interface depends on the Fermi level difference between the organic and inorganic components,which is difficult to be controlled by the common means.Herein,a core/hybrid-shell strategy aiming for efficient interface control is proposed to tune the energy barrier of the inorganic/organic core/shell nanowire interface.The Fermi level of hybrid-shell can be effectively controlled by separating the charge carriers compared to the single-shell composites.The energy barrier of the core/hybrid-shell interface is tuned to an appropriate position,and the energy filtering effect is utilized,resulting in a substantial improvement in power factor and reduction in thermal conductivity for the prepared core/hybrid-shell composites with good air-stability and flexibility.Moreover,both the flexible p type and p-n type TE devices based on the prepared core/hybrid-shell films yield excellent output properties with the maximum power densities of 41 and 45μW·cm^(−2)at a temperature difference of ca.30 K,respectively.This study provides a novel strategy to improve the TE performance of the inorganic/organic composites,displaying great potential for low-power wearable electronics.

Regulation of Mechanical Properties of Conductive Polymer Composites

Conductive polymer composites(CPCs)are widely used in the field of organic electronics as the material basis of high-performance devices,due to their obvious advantages including electrical conductivity,lightness,processability and so on.Research on CPCs has focused on the enhancement of their electrical features and the exploration of their application prospects from conventional fields to heated emerging areas like flexible,stretchable,wearable,biological and biomedical electronics,where their mechanical properties are quite critical to determine their practical device performances.Also,a main challenge to ensure their safety and reliability is on the synergistic enhancement of their electrical behavior and mechanical properties.Herein,we systematically review the research progress of CPCs with different conductive fillers(metals and their oxides,carbon-based materials,intrinsically conductive polymers,MXenes,etc.)relying on rich material forms(hydrogel,aerogel,fiber,film,elastomer,etc.)in terms of mechanical property regulation strategies,mainly relying on optimized composite material systems and processing techniques.A summary and prospective overview of current issues and future developments in this field also has been presented.

Robust hydrogel sensors for unsupervised learning enabled sign-to-verbal translation

Highly stretchable and robust strain sensors are rapidly emerging as promising candidates for a diverse of wearable electronics.The main challenge for the practical application of wearable electronics is the energy consumption and device aging.Energy consumption mainly depends on the conductivity of the sensor,and it is a key factor in determining device aging.Here,we design a liq-uid metal(LM)-embedded hydrogel as a sensing material to overcome the bar-rier of energy consumption and device aging of wearable electronics.The sensing material simultaneously exhibits high conductivity(up to 22 S m�1),low elastic modulus(23 kPa),and ultrahigh stretchability(1500%)with excel-lent robustness(consistent performance against 12000 mechanical cycling).A motion monitoring system is composed of intrinsically soft LM-embedded hydrogel as sensing material,a microcontroller,signal-processing circuits,Bluetooth transceiver,and self-organizing map developed software for the visu-alization of multi-dimensional data.This system integrating multiple functions including signal conditioning,processing,and wireless transmission achieves monitor hand gesture as well as sign-to-verbal translation.This approach provides an ideal strategy for deaf-mute communicating with normal people and broadens the application of wearable electronics.