Publications by authors named "Shen Zexiang"

Solid-state batteries (SSBs) are under development as high-priority technologies for safe and energy-dense next-generation electrochemical energy storage systems operating over a wide temperature range. Solid-state electrolytes (SSEs) exhibit high thermal stability and, in some cases, the ability to prevent dendrite growth through a physical barrier, and compatibility with the "holy grail" metallic lithium. These unique advantages of SSEs have spurred significant research interests during the last decade.

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Article Synopsis
  • Van der Waals semiconductors, like two-dimensional transition-metal dichalcogenides, have potential for advanced thin optoelectronic devices, but improving their light interaction is crucial for practical use.
  • This study demonstrates ultrastrong exciton-plasmon coupling at room temperature in tungsten disulfide layers using a innovative metasurface design on a flexible polymer.
  • The research achieves notable coupling strengths, reaching 0.164 for quadrilayers, indicating significant potential for these materials in future low-dimensional semiconductor applications.
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The unique two-dimensional layered structure of BiOCl makes it highly promising for energy storage applications. In this study, we successfully synthesized BiOCl nanoparticles encapsulated in N-doped carbon nanonecklaces (BiOCl NPs/N-CNNs) using well-established electrospinning and solvothermal substitution. As an anode material for lithium-ion batteries, BiOCl NPs/N-CNNs exhibited enhanced rate performance, delivering a capacity of 220.

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  • Solid-state sodium metal batteries (SSBs) require solid electrolyte (SE) materials that have high ionic conductivity and good compatibility with electrodes for effective performance.
  • The study introduces NaSmSiO SE, which shows remarkable room-temperature ionic conductivity (2.9 × 10 S cm) and a low activation energy (0.15 eV), resulting in exceptional cycling life and critical current density in battery applications.
  • The outstanding performance is attributed to an electrochemically induced crystalline-to-amorphous transition that improves ionic transport and interfacial properties, leading to impressive cycling performance with zero capacity loss over 4000 cycles.
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Excitonic resonance in atomically thin semiconductors offers a favorite platform to study 2D nanophotonics in both classical and quantum regimes and promises potentials for highly tunable and ultra-compact optical devices. The understanding of charge density dependent exciton-trion conversion is the key for revealing the underlaying physics of optical tunability. Nevertheless, the insufficient and inefficient light-matter interactions hinder the observation of trionic phenomenon and the development of excitonic devices for dynamic power-efficient electro-optical applications.

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Layered vanadium-based oxides are the promising cathode materials for aqueous zinc-ion batteries (AZIBs). Herein, an in situ electrochemical strategy that can effectively regulate the interlayer distance of layered NH V O quantitatively is proposed and a close relationship between the optimal performances with interlayer space is revealed. Specifically, via increasing the cutoff voltage from 1.

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Realizing perfect light absorption in stacked thin films of dielectrics and metals through critical light coupling has recently received intensive research attention. In addition, realizing ultra-thin perfect absorber and tunable perfect absorber in the visible spectrum is essential for novel optoelectronics applications. However, the existing thin film stacks cannot show tunable perfect absorption in a wide-angle range.

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Hybrid organic-inorganic lead halide perovskite nanoparticles are promising candidates for optoelectronic applications. This investigation describes the structural and optical properties of MA Cs PbBr mixed cation colloidal nanoparticles spanning the complete compositional range of Cs substitution. A monotonic progression in the cubic lattice parameter () with changes in the Cs content confirmed the formation of mixed cation materials.

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Selenium-based materials are considered as desirable candidates for potassium-ion and sodium-ion storage. Herein, an in situ fabrication method is developed to prepare an integrated cuprous selenide electrode by means of directly chemical selenization of the copper current collector with commercial selenium powder. Interestingly, only the electrolyte of 1 m potassium hexafluorophosphate dissolved in 1,2-dimethoxyethane with higher highest occupied molecular orbital energy and lower desolvation energy facilitates the formation of polyselenide intermediates and the further selenization of the copper current collector.

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Optoelectronic materials that allow on-chip integrated light signal emitting, routing, modulation, and detection are crucial for the development of high-speed and high-throughput optical communication and computing technologies. Interlayer excitons in 2D van der Waals heterostructures, where electrons and holes are bounded by Coulomb interaction but spatially localized in different 2D layers, have recently attracted intense attention for their enticing properties and huge potential in device applications. Here, a general view of these 2D-confined hydrogen-like bosonic particles and the state-of-the-art developments with respect to the frontier concepts and prototypes is presented.

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To meet the ever-growing demand for advanced rechargeable batteries with light weight and compact size, much effort has been devoted to improving the volumetric capacity of electrodes. Herein, an effective strategy of polymorph engineering is proposed to boost the volumetric capacity of FeSe. Owing to the inherent metallic electronic conductivity of tetragonal-FeSe, a conductive additive-free electrode (hereafter denoted as CA-free) can be assembled with an enhanced sodium storage volumetric capacity of 1011 mAh cm , significantly higher than semiconducting hexagonal-FeSe.

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Room-temperature-high-efficiency light-emitting diodes based on metal halide perovskite FAPbI are shown to be able to work perfectly at low temperatures. A peak external quantum efficiency (EQE) of 32.8%, corresponding to an internal quantum efficiency of 100%, is achieved at 45 K.

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Conventional lithium-ion batteries embrace graphite anodes which operate at potential as low as metallic lithium, subjected to poor rate capability and safety issues. Among possible alternatives, oxides based on titanium redox couple, such as spinel LiTiO, have received renewed attention. Here we further expand the horizon to include a perovskite structured titanate LaLiTiO into this promising family of anode materials.

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The relatively sluggish lithium ion diffusion of LiNiCoMnO (NCM) is one of the fatal factors which can significantly prevent its widespread usage in high-power applications. In this work, the monodispersed hierarchical porous yolk-shell-like LiNiCoMnO (YS-NCM) with exposure to {010} electrochemical active facets was successfully synthesized, aiming to elevate the lithium ion diffusion ability and thus to enhance the electrochemical performance. The hierarchical porous nano-/microsphere morphology as well as the voids between the yolk and the shell allow for shortened Li diffusion pathways, leading to improved Li diffusion capability.

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Article Synopsis
  • Pure 2D lead-iodide perovskites have limitations in charge transport and light absorption, making them less effective for solar energy applications compared to their 3D counterparts.
  • Researchers introduced pyridinium-based templating cations to stabilize new 2D perovskites with improved structural features, resulting in better bond angles and shorter layer separations.
  • These advancements led to lower band gaps and significantly enhanced electrical and photo conductivities, outperforming traditional 2D perovskites, with the improvements traced back to the unique structural characteristics and the presence of aromatic organic dications.
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Despite layered LiNiCoMnO having drawn much attention for their high capacity and high energy density, they still endure strong capacity decay upon prolonged cycling and high C-rates, primarily due to sluggish Li and charge-transfer kinetics and detrimental parasitic reactions with the electrolyte. To address these issues, application of a surface-coating layer made of VO/LiVO on LiNiCoMnO (V-NCM) is pursued. Benefiting from the ionic conductivity of LiVO and the electronic conductivity of VO, resulting in both enhanced Li diffusion and charge-transfer kinetics, the coated material offers significantly improved C-rate capability.

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Considerable attention has been paid recently to coherent control of plasmon resonances in metadevices for potential applications in all-optical light-with-light signal modulation and image processing. Previous reports based on out-of-plane coherent control of plasmon resonances were established by modulating the position of a metadevice in standing waves. Here we show that destructive and constructive absorption can be realized in metallic nano-antennas through in-plane coherent control of plasmon resonances, which is determined by the distribution rule of electrical-field components of nano-antennas.

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Investigations of two-dimensional transition-metal chalcogenides (TMCs) have recently revealed interesting physical phenomena, including the quantum spin Hall effect, valley polarization and two-dimensional superconductivity , suggesting potential applications for functional devices. However, of the numerous compounds available, only a handful, such as Mo- and W-based TMCs, have been synthesized, typically via sulfurization, selenization and tellurization of metals and metal compounds. Many TMCs are difficult to produce because of the high melting points of their metal and metal oxide precursors.

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Theoretically, the accomplishment of phase transformation requires sufficient energy to overcome the barriers of structure rearrangements. The transition of an amorphous structure to a crystalline structure is implemented traditionally by heating at high temperatures. However, phase transformation under ambient condition without involving external energy has not been reported.

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VS anode materials with controllable morphologies from hierarchical microflower, octopus-like structure, seagrass-like structure to urchin-like structure have been successfully synthesized by a facile solvothermal synthesis approach using different alcohols as solvents. Their structures and electrochemical properties with various morphologies are systematically investigated, and the structure-property relationship is established. Experimental results reveal that Li ion storage behavior in VS significantly depends on physical features such as the morphology, crystallite size, and specific surface area.

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A lightweight, flexible, and highly efficient energy management strategy is highly desirable for flexible electronic devices to meet a rapidly growing demand. Herein, Ni-Co-S nanosheet array is successfully deposited on graphene foam (Ni-Co-S/GF) by a one-step electrochemical method. The Ni-Co-S/GF composed of Ni-Co-S nanosheet array which is vertically aligned to GF and provides a large interfacial area for redox reactions with optimum interstitials facilitates the ions diffusion.

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Tungsten ditelluride (WTe ) is a semimetal with orthorhombic T phase that possesses some unique properties such as Weyl semimetal states, pressure-induced superconductivity, and giant magnetoresistance. Here, the high-pressure properties of WTe single crystals are investigated by Raman microspectroscopy and ab initio calculations. WTe shows strong plane-parallel/plane-vertical vibrational anisotropy, stemming from its intrinsic Raman tensor.

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Article Synopsis
  • Photonic engineering, like using photonic crystal cavities, can significantly boost the spontaneous emission rate of light emitters through the Purcell effect.
  • Researchers have demonstrated that coupling monolayer molybdenum disulfide (MoS) with a 1D silicon nitride photonic crystal increases its photoluminescence intensity by four times compared to when it’s uncoupled.
  • This enhancement, coupled with the ease of fabrication and compatibility with silicon systems, makes the device a strong candidate for applications in visible solid-state cavity quantum electrodynamics (QED).
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Due to the intriguing optical and electronic properties, 2D materials have attracted a lot of interest for the electronic and optoelectronic applications. Identifying new promising 2D materials will be rewarding toward the development of next generation 2D electronics. Here, palladium diselenide (PdSe ), a noble-transition metal dichalcogenide (TMDC), is introduced as a promising high mobility 2D material into the fast growing 2D community.

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Pristine, oxidized and defunctionalized carbon nanotubes (CNTs) were studied by Raman spectroscopy, X-ray diffraction, transmission electron microscopy and low temperature nitrogen adsorption. The Raman spectra of the studied samples in the range of 900-1800 cm were deconvoluted into five components to reveal the CNT oxidation mechanism. It was found that the oxidation resulted in the reduction of graphite components and ordering of both the structured and defect part of CNTs.

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