- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Enhanced NO2 gas sensing of a single-layer MoS2 by photogating and piezo-phototronic effects
摘要： NO2 sensors with ultrahigh sensitivity are demanded for future electronic sensing systems. However, traditional sensors are considerably limited by the relative low sensitivity, high cost and complicated process. Here, we report a simply and reliable flexible NO2 sensor based on single-layer MoS2. The flexible sensor exhibits high sensitivity to NO2 gas due to ultra-large specific surface area and the nature of two-dimensional (2D) semiconductor. When the NO2 is 400 ppb (parts per billion), compared with the dark and strain-free conditions, the sensitivity of the single-layer sensor is enhanced to 671% with a 625 nm red light-emitting diode (LED) illumination of 4 mW/cm2 power under 0.67% tensile strain. More important, the response time is dramatically reduced to ～16 s and it only needs ～65 s to complete 90% recovery. A theoretical model is proposed to discuss the microscopic mechanisms. We find that the remarkable sensing characteristics are the result of coupling among piezoelectricity, photoeletricity and adsorption-desorption induced charges transfer in the single-layer MoS2 Schottky junction based device. Our work opens up the way to further enhancements in the sensitivity of gas sensor based on single-layer MoS2 by introducing photogating and piezo-phototronic effects in mesoscopic systems.
关键词： photogating effect,single-layer MoS2,ultrahigh sensitivity,flexible NO2 sensor,piezo-phototronic effect
更新于2025-09-04 15:30:14
-
Carbonyl linked carbon nitride loading few layered MoS2 for boosting photocatalytic hydrogen generation
摘要： Pristine graphitic carbon nitride g-C3N4 materials, as a novel metal-free photocatalyst with moderate activity, have attracted intense interest. However, its fast photogenerated carriers recombination always induces a relative low performance. Herein, we for the first time report one new =C=O group linked g-C3N4 (CO-C3N4) through CO2-assisted thermal polymerization of urea. It is found that the edge =C=O groups work as the photogenerated electrons collection sites, and then promote the carriers separation. The visible-light phototatalytic hydrogen evolution performance of our synthesized samples shows 1.85 times higher than that of the reference g-C3N4. To get a considerable visible-light driven photocatalytic hydrogen generation, a new few layered MoS2 with a small size (ca. 20 nm) is prepared through a liquid exfoliation, and then is loaded onto the CO-C3N4. The optimal MoS2/CO-C3N4 sample gives the photocatalytic hydrogen evolution of 1990 and 1440μmol/(g*h) under the λ > 400 and λ > 420 illumination, higher than the reported values in literatures. The sample also shows a considerable excellent photocatalytic activity of 44.3 μmol/(g*h) under LED-600 condition.
关键词： water splitting,CO-C3N4,MoS2,photocatalysis,H2 generation
更新于2025-09-04 15:30:14
-
Static and Dynamic Piezopotential Modulation in Piezo-Electret Gated MoS <sub/>2</sub> Field-Effect Transistor
摘要： The piezotronic effect links the mechanical stimuli with various semiconductor devices, promising for low-power-consuming electronic devices, sensitive sensors and interactive control system. The persistent requirement for external strains in piezotronic modulation may hinder its application in some circumstances (such as devices on rigid substrate, or complicated synergistic piezoelectric modulation on multi-device). Here, we propose an efficient method to realize piezoelectric modulation of optical and electrical properties of MoS2 FET in both static and dynamic manner, expanding the application of piezotronics. Through capacitive coupling between piezo-electret and MoS2 FET, the remanent piezo-potential can efficiently tune the Fermi level of MoS2, programming the initial electrical property for subsequent fabrication of sophisticated devices. The external strain can induce enhanced piezo-potentials to further affect the energy band bending of MoS2 channel, giving rise to high performance strain sensors (large gauge factor ~4800, fast response time ~0.15s and good durability >1000 s). The proposed static and dynamic piezopotential tuned MoS2 FET is easy to extend to devices based on other materials, which is highly desired in tunable sensory systems, active flexible electronics, and human-machine interface.
关键词： piezo-electret,optical and electric properties,mechanical sensors,MoS2 FET,piezopotential modulation
更新于2025-09-04 15:30:14
-
[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Perfect Absorber Based on Monolayer MoS2 and Nano-Silver in the Visible Regime
摘要： The monolayer MoS2 offer wide band gap and has great potential in energy storage, sensor, photonics. In this paper, we design and simulate a perfect absorber based on the local surface plasmon resonance and the coupling properties between the Ag pattern and the monolayer MoS2. The absorption value is almost 100% at peak, and the bandwidth of the absorption greater than 90% can reach 20THz. It is also polarization independent due to the fourfold rotational structural symmetry. The absorption value still remains over 90% when the incident angle increases to 60 degrees. The absorber has a great potential in many applications such as photodetectors, solar cell, sensors.
关键词： monolayer MoS2,coupling,absorber,nano-Ag,broad-angle
更新于2025-09-04 15:30:14
-
Direct synthesis of MoS <sub/>2</sub> or MoO <sub/>3</sub><i>via</i> thermolysis of a dialkyl dithiocarbamato molybdenum( <scp>iv</scp> ) complex
摘要： Direct synthesis of either 2H-MoS2 or a-MoO3 is made possible by thermolysis of the same single source precursor in either argon or air at moderate temperatures.
关键词： direct synthesis,thermolysis,MoS2,MoO3,single source precursor
更新于2025-09-04 15:30:14
-
Anomalous Positive Bias Stress Instability in MoS2 Transistors with High-hydrogen-concentration SiO2 gate dielectrics
摘要： For the first time, the anomalous positive bias stress instability of the back gated monolayer polycrystal molybdenum disulfide with field-effect high-hydrogen-concentration SiO2 gate dielectrics is reported in this letter. It is found the threshold voltage shifts exhibits a pronounced turnaround behavior from a positive shift to a negative shift when enlarging the stress voltage and stress time. We relate this anomalous positive bias instability to two physical processes, charge trapping and hydrogen release and migration.
关键词： MoS2 Transistor,Anomalous Positive Bias Stress Instability
更新于2025-09-04 15:30:14
-
Polarization-insensitive and wide-angle broadband absorption enhancement of molybdenum disulfide in visible regime
摘要： In order to remarkably enhance the absorption capability of monolayer molybdenum disulfide (MoS2), a broadband MoS2-based perfect absorber, which is inspired by metamaterial, is proposed. By using the finite-difference time-domain (FDTD) simulations, the absorption of proposed MoS2-based absorber above 94% is achieved from 594 to 809 nm. Meanwhile, the average absorptions of monolayer MoS2 enhanced up to 27% and 67% are realized from 598 to 671 nm and 710 to 801 nm, respectively. By manipulating related structural parameters, the absorption spectrum can be further broadened and shifted in a wide wavelength range. Furthermore, the proposed absorber can tolerate a relatively wide range of incident angles and demonstrate polarization-independence.
关键词： metamaterial,polarization-insensitive,wide-angle,broadband absorber,MoS2
更新于2025-09-04 15:30:14
-
Enhanced Photoelectrocatalytic H <sub/>2</sub> Evolution over Two-Dimensional MoS <sub/>2</sub> Nanosheets Loaded on Cu-Doped CdS Nanorods
摘要： Transition-metal ion doping and efficient decoration by using a co-catalyst have been proven to effectively inhibit the recombination of photogenerated electron-hole pairs and broaden the visible-light response region. Here, we have constructed MoS2 nanosheets decorated on a copper-doped CdS nanorod composite as a noble-metal-free photoelectrocatalyst. This kind of composite material was constructed through a simple solvothermal method. The morphology, structure, chemical states, photoelectrochemical properties, and other properties were tested by using a diverse range of analytical techniques. Owing to the Cu2 + doping and the excellent electron-capturing ability of MoS2, 5 % MoS2/Cu(cid:0) CdS (with 7 % Cu2 + doping in CdS) exhibits excellent hydrogen evolution reaction with a rate of 10.18 mmol h(cid:0) 1 g(cid:0) 1, which is about 48 times higher than that of pure CdS. A significant increase in the photoelectrochemical performance of the composite catalytic material benefits from the synergistic effect between CdS and MoS2 and fast interfacial charge transfer, owing to the Cu2 + doping. These findings provide a new thought for further research of the ion doping in photoelectrocatalytic field.
关键词： CdS,hydrogen evolution reaction,photoelectrochemical performance,MoS2,Cu2 + doping
更新于2025-09-04 15:30:14
-
Phase and Defect Engineering of MoS <sub/>2</sub> Stabilized in Periodic TiO <sub/>2</sub> Nanoporous Film for Enhanced Solar Water Splitting
摘要： Phase and defect engineering of the heterostructured MoS2@TiO2 nanoporous film is investigated to achieve a broad solar spectrum light absorption and high solar water splitting efficiency. The phase transition from the semiconducting 2H-MoS2 to the metallic 1T-MoS2 is achieved by a hydrothermal exfoliation treatment. Experimental studies elucidate that the solar water splitting activity is greatly improved by forming 1T-MoS2 along with increasing S-vacancies because of the significantly enhanced surface plasmon resonance. The mixed-phase MoS2@TiO2 film shows a high H2 yield rate of 308 μmol h?1 cm?2 and long-term durability for 30 h, which is superior to the state-of-the-art catalysts for solar water splitting. This study offers a universal and efficient avenue to rationalize the plasmonic catalysts for solar water splitting and other energy and environmental applications.
关键词： solar water splitting,defect engineering,MoS2,heterostructures,phase transitions
更新于2025-09-04 15:30:14
-
Magnetically Recyclable MoS <sub/>2</sub> /Fe <sub/>3</sub> O <sub/>4</sub> Hybrid Composite as Visible Light Responsive Photocatalyst with Enhanced Photocatalytic Performance
摘要： Photocatalysis is one of the most promising technologies in wastewater treatment. However, the inactivity to visible light and the inconvenience to recycle severely limit its practical application. In this work, via a facile hydrothermal method, Fe3O4 NPs were integrated onto the surfaces of 3D ball-flower-like MoS2 microspheres as efficiently visible light responsive and magnetically recyclable photocatalysts. Experimental results indicate that, an optimal loading amount (20 wt.%) of Fe3O4 NPs can not only effectively enhance the photocatalytic ability of the MoS2/Fe3O4 (MF) hybrid composite with approximately 2 times better than pure MoS2, but also make it conveniently recycle from water by an external magnetic field. The photoelectrochemical studies also reveal that the incorporation of Fe3O4 NPs can effectively enhance the charge transfer rate and accelerate separation of photo-induced charge carriers. The surface catalytic mechanism of MF hybrid composite was also explored through XPS spectra. With both the excellent photocatalytic performance and magnetical recyclability, the 20wt%-MF hybrid composite is considered to be a promising and competitive photocatalyst for wastewater treatment utilizing solar energy.
关键词： magnetical recyclability,Fe3O4 NPs,MoS2,photocatalyst,visible light responsive
更新于2025-09-04 15:30:14