查找使用阿拉丁产品的科研文献

Ultrasensitive room temperature NO2 sensors based on liquid phase exfoliated WSe2 nanosheets

Rensong Guo,Yutong Han,Chen Su,Xinwei Chen,Min Zeng,Nantao Hu,Yanjie Su,Zhihua Zhou,Hao Wei,Zhi Yang

Semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising gas-sensing materials due to their large surface-to-volume ratio, layered structures, susceptible surfaces, and excellent conductivities. Herein, a simple and effective method has been developed to exfoliate tungsten diselenide (WSe 2 ) into few-layered nanosheets with N- methyl-2-pyrrolidone (NMP) as a dispersant. The gas sensor based on the as-synthesized WSe 2 nanosheets shows an extremely high response (50 ppb, 5.06) under a low detection concentration of nitrogen dioxide (NO 2 ) at room temperature (25 °C), which is much higher than many other reports for 2D TMDs-based gas sensors. Additionally, our sensor also exhibits a response of 11.01 to 10 ppm NO 2 , an excellent selectivity, and a reliable long-term stability within 8 weeks. It is expected that the outstanding performances of the gas sensors based on WSe 2 nanosheets reported in the present work will make WSe 2 a promising candidate for ultrasensitive NO 2 sensing applications.

Topotactic Conversion of Two-Dimensional WSe2 into Atomically Thin Nonlayered Metal Nitrides

Wenjun Liu,Tao Zhang,Canlei Wu,Dachuan Zhang,Guoyi Zhao,Shukai Wang,Zishen Fang,Xiubin Li,Kenji Watanabe,Takashi Taniguchi,Jing Li

To date, much of the synthesis efforts pertaining to atomically thin materials have been directed toward van der Waals layered structures. When nonlayered materials are thinned down to the atomic scale, they exhibit markedly different emergent properties compared with their bulk counterparts. However, the lack of a scalable synthesis technique for atomically thin nonlayered materials possessing single crystallinity poses a substantial barrier to exploring their intrinsic physical properties and potential applications. Here, we present a topotactic synthesis approach for producing atomically thin nonlayered tungsten dinitride (WN2) single crystals, utilizing van der Waals layered tungsten diselenide (WSe2) as precursor materials. Our investigations reveal the conversion of even bilayer WSe2 into WN2 with high degrees of single crystallinity and nitrogen-rich elemental composition. Employing an h-BN mask-assisted spatially controlled topotactic conversion strategy, we fabricate lateral WN2–WSe2 heterojunctions, leading to a notable enhancement in the on–off ratio compared to conventional Pt/WSe2 planar contacts. Furthermore, local hydrogen evolution reaction (HER) measurements highlight the improved electrocatalytic activity of WN2 compared to WSe2. Our study provides insights into scalable synthesis methods for atomically thin nonlayered materials and offers a promising platform for developing transitional metal nitride (TMN)-based electronics and advanced catalysts.

Magnetron sputtering fabrication and photoelectric properties of WSe2 film solar cell device

Xu Mao,Jianpeng Zou,Hongchao Li,Zhengqi Song,Siru He

Tungsten diselenide (WSe 2 ) films with different growing orientations exhibit diverse photoelectric properties. The WSe 2 film with C-axis⊥substrate texture has been prepared and applied to thin-film solar cells. W nanofilms with a thickness of 270 nm were deposited onto the Mo bottom electrode and then heat-treated in selenium vapor to synthesize WSe 2 films with a thickness of 1 μm. ZnO films were deposited onto WSe 2 films to form a P-N junction and ITO films were deposited subsequently as the conductive layer. X-ray diffractometry, scanning electron microscopy and UV-vis-NIR spectro-analysis instrument were employed to analyze the phase composition, optical absorptivity and micromorphology of WSe 2 films and the WSe 2 solar cell device. WSe 2 films exhibit excellent photoelectric performance with an optical absorption coefficient greater than 10 5  cm −1 across the visible spectrum. The calculated direct and indirect band gap of the WSe 2 films is 1.48 eV and 1.25 eV, respectively. With the application of standard glass/Mo/WSe 2 /ZnO/ITO/Ag device structure, the open-circuit voltage of the battery device is 82 mV. The short-circuit current density is 2.98 mA/cm 2 and the filling factor is 0.32. The photoelectric conversion efficiency of the WSe 2 film solar cell device is 0.79%.

Highly Polarized Light Emission of Monolayer WSe2 Coupled with Gap-Plasmon Nanocavity

Guangpeng Zhu,Xiuqi Shi,Guangyan Huang,Kaizhen Liu,Wei Wei,Qianqian Guo,Wei Du,Tao Wang

As contemporary star materials, 2D monolayer semiconductors have drawn huge research interests owing to their striking electrical and optical properties, rendering them ideal candidates as building blocks for novel optoelectronic devices. Towards light emitting devices with extended functions, it is necessary to manipulate the polarization of light emission from monolayer semiconductors. However, most of these monolayer semiconductors exhibit no or very limited polarization sensitivity inherited from their structural anisotropy, making it challenging to develop highly polarized light sources. Herein, by embedding monolayer tungsten diselenide (WSe 2 ) in a nanowire-on-film nanocavity, highly polarized light emission is demonstrated, featuring degree of polarization (DoP) of ≈99%. The highly anisotropic light emission originates from the near-field coupling between the WSe 2 monolayer with the polarization-dependent gap plasmons of the nanowire-on-film nanocavity. Moreover, as the width of the nanowire essentially defines the gap-plasmon resonance of the nanowire-on-film nanocavity, the anisotropy of the highly polarized light emission is systematically tuned by changing the nanowire width. The findings pave the way for engineering anisotropic optical properties of monolayer semiconductors and will boost the development of functional polarization-sensitive 2D optoelectronic devices.

PVP intercalated metallic WSe2 as NIR photothermal agents for efficient tumor ablation

Oyawale Adetunji Moses,Malik Ihsanullah Khan,Qi Fang,Liu Qin,Zia ur Rehman,Youkui Zhang,Cao Deng Feng,Yinchu Ma,XinFeng Tang,Chuanqiang Wu,Mukhtar Lawan Adam,Dake Huang,Hang Liu,Li Song

Transition metal dichalogenides (TMDCs) with unique layered structures hold promising potential as transducers for photothermal therapy. However, the low photothermal conversion efficiency and poor stability in some cases limit their practical applications. Herein, we demonstrate the fabrication of ultrathin homogeneous hybridized TMDC nanosheets and their use for highly efficient photothermal tumor ablation. In particular, the nanosheets were composed of metallic WSe2 intercalated with polyvinylpyrrolidone (PVP), which was facilely prepared through a solvothermal process from the mixture of selenourea crystals, WCl6 powder along with PVP polymeric nanogel. Our characterizations revealed that the obtained nanosheets exhibited excellent photothermal conversion efficiency, therapeutic demonstration with improved biocompatibility and physiological stability attributing to the combined merits of metallic phase of WSe2 and hydrophilic PVP insertion. Both the histological analysis of vital organs and in vitro/in vivo tests confirmed the nanosheets as actively effective and biologically safe in this phototherapeutic technique. Findings from this non-invasive experiment clearly emphasize the explorable therapeutic efficacy of the layered-based hybrid agents in future cancer treatment planning procedures.

Self-powered photodetectors based on stacked WSe2/graphene/SnS2 p-g-n heterostructures

Hemiao Wang,Yurui Wang,Xin Li,Xiaolian Liu,Xin Zheng,Yueqin Shi,Minxuan Xu,Jian Zhang,Qi Zhang

The insertion of a graphene interlayer between van der Waals (vdW) materials could suppress the interlayer recombination to improve interface quality and facilitate charge transport. However, its effect on photovoltaic-mode detectors has rarely been explored. Here, self-powered photodetectors based on WSe 2 /graphene/SnS 2 vdW heterojunctions were assembled and the impact of adding graphene interlayer on its performance was investigated. The p-g-n heterostructure exhibits a photovoltaic characteristic, V OC = 0.13 V and I SC = 0.12 nA under illumination of 2.98 mW/cm 2 @405 nm, lower than that of a control (WSe 2 /SnS 2 ) counterpart ( V OC = 0.19 V and I SC = 1.15 nA). Yet an FF value up to 48.16 % was obtained under an irradiation power density of 0.332 mW/cm 2 @405 nm, which is visibly higher than that of bare WSe 2 /SnS 2 vdW heterostructure . The insertion of graphene interlayer is deemed to reduce the charge traps between vdW materials that are caused by the large concentration difference of majority carriers. However, in case of vdW heterostructure, the subsequently increased leakage current makes the junction less ideal. Thereby interface engineering methods should be used with caution to tune vdW heterostructures on the nanoscale .

Anisotropy and synaptic plasticity in CrSBr/WSe2 heterojunction for advanced neural network applications

Zhao Yang,Yu Hong-Bin,Zhao Chun-Yu,Kong De-Nan,Wang Dai-Nan,Fu Long-Yi,Hu Qing-Mei,Li Dian,Zang Tian-Yu,Zheng Shou-Jun,Zhou Yao,Zhou Jia-Dong

Employing two-dimensional (2D) synaptic devices to develop a brain-inspired neuromorphic computing system is a promising approach to overcoming the limitations of the von Neumann architecture. However, isotropic 2D materials are predominantly utilized to fabricate synaptic devices. Research on inherently anisotropic 2D materials in synaptic devices remains scarce. Here, we report an intrinsically anisotropic material, CrSBr, which exhibits optoelectronic properties with significant angular dependence, achieving a carrier mobility ratio as high as 7.83 between the a -axis and b -axis. Based on this, we couple the in-plane anisotropy into the synaptic device and construct CrSBr/WSe 2 multi-terminal device. This device can be regulated by the gate voltage and laser, exhibiting storage and synaptic behaviors dependent on the a and b axes. Furthermore, we apply the synaptic property to achieve image recognition. Due to the anisotropic response to identical external stimulus, the a -axis conductance trend transits from nonlinear to approximately linear within the multi-terminal conductance framework. This multi-terminal synapse model achieves a recognition rate of up to 91% on the Fashion-MNIST database, significantly outperforming single-terminal recognition performance. Our work introduces a novel approach to anisotropic artificial synapses for simulated image recognition and establishes a foundation for developing AI systems with enhanced recognition rates. Graphical abstract

pH-responsive laminar WSe2 membrane with photocatalytic antifouling property for ultrafast water transport

Fengshun Zhang,Li-Juan Yu,Jingchong Liu,Lanlan Hou,Shuhui Li,Huiyu Chai,Hui Li,Zhirong Xin,Qingzhong Li,Zhimin Cui,Nü Wang,Lei Jiang,Yong Zhao

Separation membrane with tunable nanochannels displays desirable performance in water treatment. While designing nanogating membranes with superior permeability and antifouling properties still remains a challenge. Here, we report a smart pH-responsive nanogating membrane by assembling two-dimensional polyacrylic acid (PAA) grafted tungsten selenide (WSe 2 ) nanosheets . The nanochannel size of WSe 2 /PAA membrane varies with the swell or shrink of PAA chains that are regulated by pH, therefore leads to controllable separation capabilities towards mixed molecules solution. The membrane exhibits ultrafast water permeability because of the expanded interlayer space between WSe 2 nanosheets and weak interaction between WSe 2 and water molecules. Moreover, by virtue of the photocatalytic characteristic of WSe 2 , the membrane shows enhanced antifouling property. This WSe 2 /PAA nanogating membrane has great potential applications in nanofluidics system and complex chemical separation.

Size effect of WSe2 on red passively Q-switched fiber laser output performance

Duanduan Wu,Zhenrong Guo,Jian Peng,Jian Weng,Zhiping Cai,Huiying Xu

High-Performance Artificial Synapse Based on CVD-Grown WSe2 Flakes with Intrinsic Defects

Zihao Guo,Jinhui Liu,Xu Han,Fangyuan Ma,Dongke Rong,Jianyu Du,Yehua Yang,Tianlin Wang,Gengwei Li,Yuan Huang,Jie Xing

High-performance artificial synaptic devices with rich functions are highly desired for the development of an advanced brain-like neuromorphic system. Here, we prepare synaptic devices based on a CVD-grown WSe2 flake, which has an unusual morphology of nested triangles. The WSe2 transistor exhibits robust synaptic behaviors such as excitatory postsynaptic current, paired-pulse facilitation, short-time plasticity, and long-time plasticity. Furthermore, due to its high sensitivity to light illumination, the WSe2 transistor exhibits excellent light-dosage-dependent and light wavelength-dependent plasticity, which endow the synaptic device with more intelligent learning and memory functions. In addition, WSe2 optoelectronic synapses can mimic “learning experience” behavior and associative learning behavior like the brain. An artificial neural network is simulated for pattern recognition of hand-written digital images in the MNIST data set and the best recognition accuracy could reach 92.9% based on weight updating training of our WSe2 device. Detailed surface potential analysis and PL characterization reveal that the intrinsic defects generated in growth are dominantly responsible for the controllable synaptic plasticity. Our work suggests that the CVD-grown WSe2 flake with intrinsic defects capable of robust trapping/de-trapping charges holds great application prospects in future high-performance neuromorphic computation.

Robust Deposition of Sub-Millimeter WSe2 Drive Ultrasensitive Gate-Tunable 2D Material Photodetectors

Mengmeng Yang,Zhongtong Luo,Wei Gao,Menglong Zhang,Le Huang,Yu Zhao,Jiandong Yao,Fugen Wu,Jingbo Li,Zhaoqiang Zheng

2D semiconductors are regarded as the potential channel materials for high-performance integrated optoelectronics. However, the absence of an effective photoconductive gain mechanism and the adverse effects from traditional SiO 2 substrate prevent the further breakthrough of the photosensitivity of 2D semiconductors-based photodetectors. Here, an ingenious out-of-plane heterostructure is proposed for boosting the photosensitivity. Sub-millimeter scale (>700 µm) tri-layer WSe 2 with high quality and uniformity is robustly deposited and integrated with 2D photosensitive channels for gate-tunable photodetection. The WSe 2 with naturally passivated surface can not only serve as a substrate passivation layer to mitigate the detrimental substrate effects, but also introduces vertical built-in fields, which efficiently separates the photogenerated carriers and produces high photoconductive gain. Under gate voltage modulation, the proposed InSe photodetector exhibits a series of excellent performances, including responsivity of 112 A W −1 , detectivity of 8.6 × 10 12 Jones, light on/off ratio of 1.3 × 10 4 and rise/decay time of 29.1/15.3 ms. More inspiringly, this heterostructure scheme is universally applicable to 2D WS 2 photodetector and also significantly improves its photosensitivity, demonstrating broad applicability. This research will provide helpful guidance for the design and optimization of customizable optoelectronic devices based on 2D semiconductors.

Atomically Modulated WSe2 Clusters with Enhanced Biocatalytic Activity for Acute Liver Injury Management

Ke Chen,Ziyi Peng,Ruoli Zhao,Fangzhen Tian,Chenxi Li,Lijie Zhang,Huihui Huang,Di Zhao,Shuo Wang,Yuxuan Huo,Xiao-Dong Zhang,Hao Wang,Shaofang Zhang,Jingwen Zhao,Huanhuan Qiao,Ruiping Zhang

Two-dimensional WSe2 has attracted considerable attention owing to its tunable electronic structure and intrinsic catalytic activity. However, the catalytic redox performance of pure WSe2 remains limited by insufficient charge-transfer efficiency and suboptimal catalytic kinetics in complex oxidative environments. Herein, we constructed a series of ultrasmall WSe2 clusters via atomic-level regulation. This strategy could modulate their electronic configuration and enhance their catalytic performance. The resulting approximately 2 nm M-WSe2 (M = Ce, Pt, Fe) clusters exhibited total antioxidant capacity 2.3- to 4.3-fold higher than that of pure WSe2. Their multienzyme-like activity was increased by 2.2- to 44-fold, and they exhibited broad-spectrum free radical scavenging ability. These atomic-level modulated clusters effectively protected hepatocytes from oxidative stress damage and inhibited macrophage inflammatory response. In the acetaminophen-induced acute liver injury model, M-WSe2 significantly alleviated hepatic oxidative damage and restored redox homeostasis, with serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels reduced by approximately 73% and 76%, respectively. Notably, these clusters exhibited favorable biosafety. Through atomic-scale design, this study provided a rational strategy for developing high-performance antioxidant clusters for oxidative stress and inflammation-related liver injury.