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Enhancement of efficiency of single walled carbon nanotubes-n-type silicon solar cells using molybdenum disulfide
摘要： This study focuses on the improvement of ef?ciency of single walled carbon nanotubes and n-type silicon (SWCNTs-n-type-Si) based solar cells using molybdenum disul?de (MoS2). Initially, different hybrid MoS2/SWCNTs-n-type-Si ?lms were fabricated and optimized the best performing cell. The ?lms were tested through scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy to check their surface morphology, topography, and elemental characteristics, respectively. The long cylinder shape for SWCNTs and crystal sheet for MoS2 were observed, where the SWCNTs were distributed randomly among the MoS2 ?akes. Raman spectra showed the characteristics peaks of SWCNTs, Si, and MoS2. The addition of MoS2 in optimized ?lm has improved the ef?ciency of SWCNTs-n-type-Si solar cells approximately 49%.
关键词： Energy diagram,MoS2,Solar cells,Silicon,Morphology,SWCNTs
更新于2025-09-19 17:13:59
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A molybdenum disulfide quantum dots-based ratiometric fluorescence strategy for sensitive detection of epinephrine and ascorbic acid
摘要： In this paper, a novel and sensitive ratiometric fluorescence strategy for the detection of epinephrine (EP) and ascorbic acid (AA) was established based on the fluorescence resonance energy transfer (FRET) between the molybdenum disulfide quantum dots (MQDs) and the fluorescent oxidative polymerization product (PEP-PEI) of EP in polyethyleneimine (PEI) aqueous solution. The continuous formation of PEP-PEI can lead to the fluorescence quenching of MQDs at 414 nm while the fluorescence of PEP-PEI at 522 nm gradually increased. The introduction of AA can inhibit the oxidative polymerization process of EP due to the strong reducibility of AA, resulting in the fluorescence recovery of MQDs at 414 nm and the fluorescence decreasing of PEP-PEI at 522 nm. Therefore, EP and AA can be monitored by measuring the ratio of the fluorescence intensities at 522 nm and 414 nm. A good linear calibration of I522/I414 versus EP and AA concentrations were obtained within 0.2e40 mM and 0.5e40 mM, respectively. And the detection limit was 0.05 mM for EP and 0.2 mM for AA. Furthermore, the developed ratiometric fluorescence method with high sensitivity and selectivity was applied for EP in human urine samples and AA in human serum samples determination with satisfactory results obtained.
关键词： Epinephrine,Polyethyleneimine,Ascorbic acid,MoS2 quantum dots,Ratiometric fluorescence
更新于2025-09-19 17:13:59
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Transparent MoS <sub/>2</sub> /PEDOT Composite Counter Electrodes for Bifacial Dye-Sensitized Solar Cells
摘要： Dye-sensitized solar cells (DSSCs) are solar energy conversion devices with high efficiency and simple fabrication procedures. Developing transparent counter electrode (CE) materials for bifacial DSSCs can address the needs of window-transparent-type building-integrated photovoltaics (BIPVs). Herein, transparent organic?inorganic hybrid composite films of molybdenum disulfide and poly(3,4-ethylenedioxythiophene) (MoS2/PEDOT) are prepared to take full advantage of the conductivity and electrocatalytic ability of the two components. MoS2 is synthesized by hydrothermal method and spin-coated to form the MoS2 layer, and then PEDOT films are electrochemically polymerized on top of the MoS2 film to form the composite CEs. The DSSC with the optimized MoS2/PEDOT composite CE shows power conversion efficiency (PCE) of 7% under front illumination and 4.82% under back illumination. Compared with the DSSC made by the PEDOT CE and the Pt CE, the DSSC fabricated by the MoS2/PEDOT composite CE improves the PCE by 10.6% and 6.4% for front illumination, respectively. It proves that the transparent MoS2/PEDOT CE owes superior conductivity and catalytic properties, and it is an excellent candidate for bifacial DSSC in the application of BIPVs.
关键词： building-integrated photovoltaics,transparent counter electrode,MoS2/PEDOT composite,bifacial illumination,Dye-sensitized solar cells
更新于2025-09-19 17:13:59
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Oxygen doped MoS <sub/>2</sub> quantum dots for efficient electrocatalytic hydrogen generation
摘要： In this study, we report an oxygen-doped MoS2 quantum dot (O–MoS2 QD) hybrid electrocatalyst for the hydrogen evolution reaction (HER). The O–MoS2 QDs were prepared with a one-pot microwave method by hydrazine-mediated oxygen-doping. The synthetic method is straightforward, time-saving, and can be applied in large scale preparation. Ultra-small O–MoS2 QDs with the average size of 5.83 nm and 1–4 layers can be uniformly distributed on the surface of reduced graphene oxide (RGO). Benefited from the unique structure and the doping effect of oxygen in the MoS2 QDs and the great number of active sites, the O–MoS2 QD hybrid displayed outstanding electrocatalytic performance toward HER. A low overpotential of 76 mV at 10 mA/cm2 and a Tafel slope of 58 mV/dec were obtained in an acidic solution toward HER. Additionally, the resultant O–MoS2 QD hybrid also exhibited excellent stability and durability toward HER, displaying negligible current density loss after 1000 cycles of cyclic voltammetry. The design and synthesis of the electrocatalyst in this work open up a prospective route to prepare active and stable electrocatalysts toward substituting precious metals for hydrogen generation.
关键词： electrocatalytic hydrogen generation,oxygen-doped MoS2 quantum dots,microwave synthesis,reduced graphene oxide,hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Exploring conduction mechanism and photoresponse in <i>P-</i> GaN <i>/n-</i> MoS <sub/>2</sub> heterojunction diode
摘要： Mixed-dimensional heterostructures have shown their potential in electronic devices. However, their functionality is limited by a complete understanding of the contacts and the current transport behavior. Here, we explore the electrical properties of the P-n heterojunction diode fabricated using p-type gallium nitride and layered molybdenum disulfide. The resulting P-n diode is rectifying in nature with current rectification of three orders of magnitude. The careful choice of Ohmic contacts on both the semiconductors reveals distinctly rectifying behavior of the heterojunction diode. The as-fabricated diode is tested at various temperatures, and the conduction mechanism in the device is analyzed based on the temperature dependent electrical characterizations. In addition, photoresponse characterization reveals that the P-n heterojunction is highly sensitive to a 405 nm laser with a high responsivity of 444 A/W at a reverse bias voltage of 5 V and shows photovoltaic behavior. The heterojunction diode acts as a self-powered photodetector. Our findings show the potential of the MoS2/GaN heterojunction in highly efficient photodetector applications.
关键词： conduction mechanism,heterojunction diode,photoresponse,P-GaN,n-MoS2
更新于2025-09-19 17:13:59
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Laser annealing towards high-performance monolayer MoS2 and WSe2 field effect transistors
摘要： The transition metal dichalcogenides (TMDCs) have been intensively investigated as one of promising nanoelectronic and optoelectronic materials. However, the pervasive adsorbates on the surface of monolayer TMDCs, including oxygen and water molecules from the ambient environments, predominately degrade the device performance, thus hindering the precise applications. In this work, we report the effect of laser irradiation on the transport and photoresponse of monolayer MoS2 and WSe2 devices, and this laser annealing process is demonstrated as one straightforward approach to remove the physically adsorbed contaminations. Compared with vacuum pumping and in-situ thermal annealing treatments, the field-effect transistors after the laser annealing show more than one order of magnitude higher on-state current, and no apparent degradation of device performance at low temperature. The mobility of monolayer WSe2 devices can be enhanced by 3-4 times, and for single-layered MoS2 devices with the commonly used SiO2 as the back-gate, the mobility increases by 20 times, reaching 37 cm2 ? V?1 ? s?1. The efficient cleaning effect of the laser annealing is also supported by the reduction of channel and contact resistances revealed by the transmission line experiment. Further, the enhanced photocurrent by a factor of 10 has been obtained in the laser annealed device. These findings pave the way for the high-performance monolayer TMDCs-based electronic and optoelectronic devices with the clean surface and intrinsic properties.
关键词： TMDCs,monolayer MoS2,photoresponse,field-effect transistors,laser annealing,monolayer WSe2
更新于2025-09-19 17:13:59
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17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS <sub/>2</sub> as a Replacement for PEDOT:PSS
摘要： The application of liquid-exfoliated 2D transition metal disulfides (TMDs) as the hole transport layers (HTLs) in nonfullerene-based organic solar cells is reported. It is shown that solution processing of few-layer WS2 or MoS2 suspensions directly onto transparent indium tin oxide (ITO) electrodes changes their work function without the need for any further treatment. HTLs comprising WS2 are found to exhibit higher uniformity on ITO than those of MoS2 and consistently yield solar cells with superior power conversion efficiency (PCE), improved fill factor (FF), enhanced short-circuit current (JSC), and lower series resistance than devices based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and MoS2. Cells based on the ternary bulk-heterojunction PBDB-T-2F:Y6:PC71BM with WS2 as the HTL exhibit the highest PCE of 17%, with an FF of 78%, open-circuit voltage of 0.84 V, and a JSC of 26 mA cm?2. Analysis of the cells’ optical and carrier recombination characteristics indicates that the enhanced performance is most likely attributed to a combination of favorable photonic structure and reduced bimolecular recombination losses in WS2-based cells. The achieved PCE is the highest reported to date for organic solar cells comprised of 2D charge transport interlayers and highlights the potential of TMDs as inexpensive HTLs for high-efficiency organic photovoltaics.
关键词： liquid exfoliation,2D transition metal disulfides,nonfullerene organic solar cells,hole transport layers,MoS2,WS2
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 19th International Conference on Nanotechnology (IEEE-NANO) - Macao (2019.7.22-2019.7.26)] 2019 IEEE 19th International Conference on Nanotechnology (IEEE-NANO) - Pulsed Laser Deposited MoS <sub/>2</sub> for the Fabrication of MoS <sub/>2</sub> /Graphene Photodetector
摘要： Since the 21st century, with the continuous development of technology, much tremendous progress has been made in the microelectronics industry. When the channel of the device is reduced to the nanometer scale, the silicon-based semiconductor has approached its physical limit, and the performance begins to decrease, so the traditional silicon-based semiconductor industry has entered the research bottleneck. Compared with traditional silicon-based semiconductors, two-dimensional materials are increasingly used in the semiconductor industry due to their ultra-thin atomicity and semiconductor characteristics. As a typical representative of two-dimensional materials, MoS2 is widely used for device preparation, including gas sensors, phototransistors, flexible thin film transistors, lithium-ion battery electrodes and heterojunction diodes. However, achieving high-quality, controllable large-area preparation of MoS2 is still a major problem, which seriously hinders the development of MoS2 in the application field. In this paper, pulsed laser deposition is used to prepare large-sized MoS2 by controlling different deposition time.
关键词： Atomic layer deposition,MoS2,pulsed laser deposition
更新于2025-09-19 17:13:59
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MoS2/Ni-CoSx porous nanocubes derived from Ni–Co prussian-blue analogs as enhanced Pt-free electrode catalysts for high-efficiency dye-sensitized solar cells
摘要： Owing to the modifiable compositions and morphologies, high-efficiency clean energy catalysts with complex functional structures attract wide-ranging attention. Herein, this report focuses on the controllably morphological MoS2-doped NiS2/Co3S4 nanocubes which are derived from nickel-cobalt Prussian-blue analogs. After annealing in N2 flow, MoS2/Ni-CoSx porous nanocubes are prepared via regulating the reactant ratios (1/2, 1/1 and 2/1) between (NH4)2MoS4 and Ni–Co Prussian-blue analogs. In the synthesis progress, (NH4)2MoS4 is applied as a bifunctional dopant source, which can expediently offer Mo and S elements simultaneously. The quaternary porous MoS2/Ni-CoSx (1/1) with the reasonable chemical composition, considerable specific surface area (86.7 m2 g?1) and excellent electrocatalytic property can be selected as the representative counter electrode catalyst in dye-sensitized solar cells. Furthermore, the solar cell with MoS2/Ni-CoSx (1/1) exhibits a higher power conversion efficiency (9.80%) than that of Pt (8.19%) under a standard irradiation.
关键词： Prussian-blue analogs,Dye-sensitized solar cells,(NH4)2MoS4,Nanocubes,MoS2/Ni-CoSx,Electrocatalytic property
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 5th International Conference for Convergence in Technology (I2CT) - Bombay, India (2019.3.29-2019.3.31)] 2019 IEEE 5th International Conference for Convergence in Technology (I2CT) - Growth of Different Microstructure of MoS <sub/>2</sub> through Controlled Processing Parameters of Chemical Vapor Deposition Method
摘要： The anisotropic bonding in layered materials crystallize to form different structure such as smooth films, nanotubes, and fullerene-like nanoparticles. Here, the growth of different microstructure of MoS2 via chemical vapor deposition (CVD) method through controlled processing parameters is reported. Scanning electron microscopy and Raman spectroscopy ascertained the MoS2 on insulating substrate (SiO2/Si). It was observed that poor sulfur environment and slow vapor flow were unable to induce complete transition from MoO3-x to MoS2 and formed intermediate MoO2.The MoS2 and MoO2/MoS2 heterostructure were synthesized via single step. In addition, by adjustment of heating rate with temperature of centre zone and vapor flow, flower like structure of MoS2 was achieved.
关键词： Sulfurization,CVD,MoS2,Layered materials,2D materials
更新于2025-09-19 17:13:59