Metal Organic framework derived carbon for ultrahigh power and long cyclic life aqueous Zn ion capacitor

In order to develop functional energy storage device,it is necessary to improve the energy and power density.As a potential candidate that can synergistically harmonize energy and power density,lithium ion capacitor(LIC)has shown exciting promises in recent years.However,in the recent years,alternative metal has been explored to replace lithium in such metal-ion capacitor system.Hence,in this work we present zinc ion capacitor(ZIC)in which zinc acts as negative electrode and Metal Organic framework(MOF)derived carbon as positive electrode.The assembled ZIC was able to demonstrate exceptional power density of 85.5 kW kg^-1 and a maximal energy density of 36.4W h kg^-1,together with 99%capacitance retention after cycling for 20000 cycles.

Graphene and other two-dimensional materials

Over the last few years,research on graphene [1-3]has progressed significantly,and as a result,a number of reallife applications of graphene have been realized [4,5].This carbon allotrope (for a review on other forms of carbon, see [6])resulted in a number of novel physical phenomena already discovered (ranging from new types of quantum Hall effect to universal optical conductivity)and dramatically expanded the range of possible applications for such materials (from transparent conductive coating to ultrafast photodetectors).

Bi_(2)S_(3) for Aqueous Zn Ion Battery with Enhanced Cycle Stability

Aqueous Zn ion batteries(ZIBs)are promising in energy storage due to the low cost,high safety,and material abundance.The development of metal oxides as the cathode for ZIBs is limited by the strong electrostatic forces between O2−and Zn2+which leads to poor cyclic stability.Herein,Bi2S3 is proposed as a promising cathode material for rechargeable aqueous ZIBs.Improved cyclic stability and fast diffusion of Zn2+is observed.Also,the layered structure of Bi2S3 with the weak van der Waals interaction between layers offers paths for diffusion and occupancy of Zn2+.As a result,the Zn/Bi2S3 battery delivers high capacity of 161 mAh g−1 at 0.2 A g−1 and good cycling stability up to 100 cycles with ca.100%retention.The battery also demonstrates good cyclic performance of ca.80.3%over 2000 cycles at 1 A g−1.The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution.This work indicates that Bi2S3 shows great potential as the cathode of ZIBs with good performance and stability.

Emerging flexible and wearable physical sensing platforms for healthcare and biomedical applications

There are now numerous emerging flexible and wearable sensing technologies that can perform a myriad of physical and physiological measurements.Rapid advances in developing and implementing such sensors in the last several years have demonstrated the growing significance and potential utility of this unique class of sensing platforms.Applications include wearable consumer electronics,soft robotics,medical prosthetics,electronic skin,and health monitoring.In this review,we provide a state-ofthe-art overview of the emerging flexible and wearable sensing platforms for healthcare and biomedical applications.We first introduce the selection of flexible and stretchable materials and the fabrication of sensors based on these materials.We then compare the different solid-state and liquid-state physical sensing platforms and examine the mechanical deformation-based working mechanisms of these sensors.We also highlight some of the exciting applications of flexible and wearable physical sensors in emerging healthcare and biomedical applications,in particular for artificial electronic skins,physiological health monitoring and assessment,and therapeutic and drug delivery.Finally,we conclude this review by offering some insight into the challenges and opportunities facing this field.

Emergence of photoluminescence on bulk MoS2 by laser thinning and gold particle decoration

We demonstrate a facile and effective approach to significantly improve the photoluminescence of bulk MoS2 via laser thinning followed by gold particle decoration. Upon laser thinning of exfoliated bulk MoSz photoluminescence emerges from the laser-thinned region. After further treatment with an AuCl3 solution, gold particles self-assemble on the laser-thinned region and thick edges, further increasing the fluorescence of bulk MoS2 28 times and the Raman response 3 times. Such fluorescence enhancement can be attributed to both surface plasmon resonance and p-type doping induced by gold particles. The combination of laser thinning and AuCl3 treatment enables the functionalization of bulk MoS2 for optoelectronic applications. It can also provide a viable strategy for mask-free and area-selective p-type doping on single MoS2 flakes.

Significantly enhanced of tungsten diselenide functionalization optoelectronic performance phototransistor via surface

Two-dimensional （2D） layered transition metal dichalcogenides （TMDs） have attracted enormous research interests and efforts towards the development of versatile electronic and optical devices, owing to their extraordinary and unique fundamental properties and remarkable prospects in nanoelectronic applications. Among the TMDs, tungsten diselenide （WSe2） exhibits tunable ambipolar transport characteristics and superior optical properties such as high quantum efficiency. Herein, we demonstrate significant enhancement in the device performance of WSe2 phototransistor by in situ surface functionalization with cesium carbonate （Cs2CO3）. WSe2 was found to be strongly doped with electrons after Cs2CO3 modification. The electron mobility of WSe2 increased by almost one order of magnitude after surface functionalization with 1.6-nm-thick Cs2CO3 decoration. Furthermore, the photocurrent of the WSe2-based phototransistor increased by nearly three orders of magnitude with the deposition of 1.6-nm-thick Cs2CO3. Characterizations by in situ photoelectron spectroscopy techniques confirmed the significant surface charge transfer occurring at the Cs2COB/WSe2 interface. Our findings coupled with the tunable nature of the surface transfer doping method establish WSe2 as a promising candidate for future 2D materials- based optoelectronic devices.

Chemically induced large-gap quantum anomalous Hall insulator states in Ⅲ-Bi honeycombs

The search for novel materials with new functionalities and applications potential is continuing to intensify.Quantum anomalous Hall(QAH)effect was recently realized in magnetic topological insulators(TIs)but only at extremely low temperatures.Here,based on our first-principles electronic structure calculations,we predict that chemically functionalized Ⅲ-Bi honeycombs can support large-gap QAH insulating phases.Specifically,we show that functionalized AlBi and TlBi films harbor QAH insulator phases.GaBi and InBi are identified as semimetals with non-zero Chern number.Remarkably,TlBi exhibits a robust QAH phase with a band gap as large as 466 meV in a buckled honeycomb structure functionalized on one side.Furthermore,the electronic spectrum of a functionalized TlBi nanoribbon with zigzag edge is shown to possess only one chiral edge band crossing the Fermi level within the band gap.Our results suggest that Ⅲ-Bi honeycombs would provide a new platform for developing potential spintronics applications based on the QAH effect.

Multiple unpinned Dirac points in group-Va single-layers with phosphorene structure

Emergent Dirac fermion states underlie many intriguing properties of graphene,and the search for them constitutes one strong motivation to explore two-dimensional(2D)allotropes of other elements.Phosphorene,the ultrathin layers of black phosphorous,has been a subject of intense investigations recently,and it was found that other group-Va elements could also form 2D layers with similar puckered lattice structure.Here,by a close examination of their electronic band structure evolution,we discover two types of Dirac fermion states emerging in the low-energy spectrum.One pair of(type-I)Dirac points is sitting on high-symmetry lines,while two pairs of(type-II)Dirac points are located at generic k-points,with different anisotropic dispersions determined by the reduced symmetries at their locations.Such fully-unpinned(type-II)2D Dirac points are discovered for the first time.In the absence of spin-orbit coupling(SOC),we find that each Dirac node is protected by the sublattice symmetry from gap opening,which is in turn ensured by any one of three point group symmetries.The SOC generally gaps the Dirac nodes,and for the type-I case,this drives the system into a quantum spin Hall insulator phase.We suggest possible ways to realise the unpinned Dirac points in strained phosphorene.