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Colloidally synthesized defect-rich $$\hbox {MoSe}_{2}$$ MoSe 2 nanosheets for superior catalytic activity
摘要： Transition metal dichalcogenide (TMD) nanosheets (NSs) with defect-rich and vertically aligned edges are highly advantageous for various catalytic applications. However, colloidal synthesis of defect-rich NSs with thickness variation has been a challenging task. Here, we report a colloidal synthesis of 2H-MoSe2 NSs having a large number of defects and vertically aligned edges, where the thickness is varied by changing the amount of coordinating solvent. The Se-vacancies in these NSs have introduced defect sites which are corroborated by the presence of additional vibration modes in Raman spectra. These NSs exhibit electrocatalytic hydrogen evolution reaction performances with a low overpotential (210–225 mV) at 10 mA cm?2 current density and a small Tafel slope (54–68 mV per decade). Moreover, these MoSe2 NSs are also employed as counter electrodes (CEs) for the fabrication of dye sensitized solar cells via a cost-effective and simplified procedure. The power conversion efficiencies of 7.02 ± 0.18%, comparable with Pt CE (7.84 ± 0.10%) could be routinely achieved. These results demonstrate a novel synthetic strategy to prepare layered TMDs with superior catalytic applications.
关键词： counter electrode,Transition metal dichalcogenides,dye sensitized solar cells,MoSe2 nanosheets,hydrogen evolution reaction
更新于2025-11-19 16:56:35
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Phase engineering and optical properties of 2D MoSe2: Promise and pitfalls
摘要： Phase engineering monolayer MoS2, selectively controlling the MoS2 2H to 1T′ transition via lithium intercalation, has driven recent excitement in the nanoscale electronics field, due to resultant MoS2 contact resistance reduction and the compatibility of MoS2 with CMOS device architecture. Here, we report the “on-chip” 2H to 1T′ transition for the related MoSe2 system, which has a smaller 1.55 eV 2H bandgap, and for which the 1T′ phase transformation should be more energetically favorable. We report the first on-chip 2H to 1T′ transformation of monolayer MoSe2 on both SiO2 and sapphire substrates. The on-chip 1T′eMoSe2 shows higher transparency despite an increased number of metallic states, indicating tunable optoelectronic properties with potential applications in transparent electrodes and energy harvesting. We also describe the challenges introduced by on-chip phase engineering via n-butyllithium exposure. Density functional theory (DFT) calculations indicate that Li+ ions are required on both sides of the MoSe2 monolayer to create a strong thermodynamic driving force for the 1T′ transformation. We observe that patterned n-butyllithium exposures can be inconsistent, with widely variable kinetics. Due to manifest n-butyllithium-engineered 1T′ MoSe2 stability concerns we propose the process is an unreliable processing technique for 2D electronics.
关键词： MoSe2,2D materials,Phase engineering,Nanomaterials
更新于2025-09-23 15:23:52
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Modulating electronic and magnetic properties of zigzag MoSe2 nanoribbons with different edge structures
摘要： In this paper, we performed the first-principles calculations to investigate the effect of different edge structures on stability, electronic and magnetic properties of zigzag MoSe2 nanoribbons and their corresponding variation by saturating the ribbon edges with H. We have taken twelve patterns of edge structure into consideration due to the chemical nonequivalence of Mo and Se atoms. We found that H-NR-u and H-NR-s have the highest stability by analysing binding energies. Specially, all of the zigzag MoSe2 nanoribbons exhibit obvious metallicity, whether they are hydrogenated or not. What's more, the pristine and hydrogenated zigzag nanoribbons have stable ferrimagnetism with a wide range of total magnetic moment 0.27–3.59 μB. The Mo-terminated nanoribbon has the largest magnetic moment and hydrogenation can significantly reduce the magnetic moment of nanoribbons. We also reveal zigzag MoSe2 nanoribbons with same terminal have very similar stability, electronic and magnetic properties, which have nothing to do with the symmetry of the system. Above all, these unique properties of zigzag MoSe2 nanoribbons have the great potential for electronic, spintronic and magnetoresistive nano-devices in the future.
关键词： Hydrogenation,Nanoribbon,Ferrimagnetism,First-principle calculation,MoSe2
更新于2025-09-23 15:23:52
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Interface Engineering of Au(111) for the Growth of 1T′-MoSe <sub/>2</sub>
摘要： Phase-controlled synthesis of two-dimensional transition metal dichalcogenides (TMDCs) is of great interest due to the distinct properties of the different phases. However, it is challenging to prepare metallic phase of group-VI TMDCs due to their metastability. At the monolayer level, interface engineering can be used to stabilize the metastable phase. Here, we demonstrate the selective growth of either single-layer 1H or 1T’-MoSe2 on Au(111) by molecular beam epitaxy; the two phases can be unambiguously distinguished using scanning tunnelling microscopy and spectroscopy. While the growth of 1H-MoSe2 is favourable on pristine Au(111), the growth of 1T’-MoSe2 is promoted by the pre-deposition of Se on Au(111). The selective growth of 1T’-MoSe2 phase on Se-pretreated Au(111) is attributed to Mo intercalation-induced stabilization of the 1T’ phase, which is supported by density functional theory calculations. In addition, 1T’ twin boundaries and 1H-1T’ heterojunctions were observed and found to exhibit enhanced tunnelling conductivity. The substrate pre-treatment approach for phase-controlled epitaxy should be applicable to other group-VI TMDCs grown on Au (111).
关键词： phase control,heterojunction,scanning tunnelling microscopy/spectroscopy,interface engineering,transition metal dichalcogenides,MoSe2
更新于2025-09-23 15:23:52
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Mechanically tuned molybdenum dichalcogenides (MoS2 and MoSe2) dispersed supramolecular hydrogel scaffolds
摘要： An intriguing way of tuning the mechanical efficiency of a supramolecular hydrogel network (SHGel) has been achieved by dispersing MoS2 and MoSe2. Depending upon the nature of chalcogens, the rheological properties of molybdenum dichalcogenides dispersed supramolecular hydrogel are varied. According to the variation of rheological properties, the morphologies of diverse molybdenum dichalcogenides dispersed hydrogel networks are changed. MoS2 enhances the mechanical performances of a supramolecular hydrogel. The incorporation of MoSe2 nano-fillers in the MoS2 dispersed supramolecular hydrogel lowers the mechanical properties gradually compared to the dispersion of pure MoS2. The dispersion of pure MoSe2 exclusively lowers the mechanical efficiency of the supramolecular hydrogel resulting in a drastic alteration of the morphological pattern of MoSe2 nano-fillers dispersed hydrogel under ambient condition.
关键词： MoSe2,Mechanical tuning,MoS2,Hydrogel,Microstructure
更新于2025-09-23 15:21:21
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Ultrathin Circular Polarimeter Based on Chiral Plasmonic Metasurface and Monolayer MoSe2
摘要： Two-dimensional materials are ideal platforms for intriguing physics and optoelectronic applications because of their ultrathin thicknesses and excellent properties in optics and electronics. Further studies on enhancing the interaction between light and two-dimensional materials by combining metallic nanostructures have generated broad interests in recent years, such as enhanced photoluminescence, strong coupling and functional optoelectronics. In this work, an ultrathin circular polarimeter consisting of chiral plasmonic metasurface and monolayer semiconductor is proposed to detect light with different circular polarization within a compact device. A designed chiral plasmonic metasurface with sub-wavelength thickness is integrated with monolayer MoSe2, and the circular-polarization-dependent photocurrent responses of right and left circularly polarized light for both left- and right-handed metasurfaces are experimentally demonstrated. The photoresponse circular dichroism is also obtained, which further indicates the remarkable performance of the proposed device in detecting and distinguishing circularly polarized light. This design offers a great potential to realize multifunctional measurements in an ultrathin and ultracompact two-dimensional device for future integrated optics and optoelectronic applications with circularly polarized light.
关键词： circular polarimeter,chiral plasmonic metasurface,MoSe2,photocurrent responses,two-dimensional materials
更新于2025-09-23 15:21:01
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Enhanced Photocatalytic Activity of 2 <i>H</i> -MoSe <sub/>2</sub> by 3 <i>d</i> Transition Metal Doping
摘要： To develop MoSe2-based photocatalysts, increasing the catalytic activity of 2H-MoSe2 is essential. In this work, the electronic and photocatalytic properties of 3d transition metal (TM) doped (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) 2H-MoSe2 were investigated by first-principles calculations. The results indicate that Sc, Ti, V, Cr, Mn, Fe and Co atoms tend to substitute the Mo atoms under Se-rich condition, while Ni, Cu and Zn atoms prefer to occupy the interstitial positions. More importantly, Sc- and Ti-doped 2H-MoSe2 can enhance the photocatalytic activity by increasing the oxidizability of photogenerated holes, suppressing the recombination of photogenerated carriers and increasing the number of catalytic active sites.
关键词： photocatalytic activity,2H-MoSe2,3d transition metal doping,electronic properties,first-principles calculations
更新于2025-09-23 15:21:01
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Influence of WSe2 buffer layer at back electrode on performance of Cu2ZnSn(S,Se)4 solar cells
摘要： CZTSSe-based solar cells with a structure of Al/ITO/ZnO/CdS/CZTSSe/p-WSe2/Mo (denoted as WSe2-CZTSSe solar cell) were prepared on the Mo-coated soda-lime glass (SLG) with a pre-sputtering metal tungsten (W) layer. Comparing with the conventional CZTSSe solar cell with a structure of Al/ITO/ZnO/CdS/CZTSSe/n-MoSe2/Mo (denoted as CZTSSe solar cell), the WSe2-CZTSSe solar cell shows a significant improvement in open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF), and so its power conversion efficiency (PCE) enhances. The largest enhancement of the PCE is from 4.13% of the CZTSSe solar cell to 5.45% of the WSe2-CZTSSe solar cell. The increased VOC and JSC are mainly due to the enhancement of photogenerated current density (JL) and decrease of reversion saturation current density (J0), while the increased FF is ascribed to the increase of shunt resistance (RSh). The influence mechanism of the WSe2 buffer layer on JL, J0 and RSh is also investigated in detail. Our results present a route of increment of PCE by reducing and even removing back contact barrier between CZTSSe and MoSe2 layers.
关键词： Cu2ZnSn(S,Se)4,Solar cell,MoSe2,Contact potential barrier,Interface,WSe2
更新于2025-09-23 15:19:57
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Sonochemical synthesis of a 2D–2D MoSe <sub/>2</sub> /graphene nanohybrid electrode material for asymmetric supercapacitors
摘要： Molybdenum selenide (MoSe2) nanosheets are prepared by a simple and facile sonochemical route. To optimize the synthesis process, the sonication is tested at three different time durations (15, 30 and 45 min) with a constant power of 500 W. In order to improve the electrochemical performance of the exfoliated MoSe2 nanosheets, we report the hybridization of 2D-MoSe2 with 2D-graphene by a simple solvothermal method. The exfoliated MoSe2 nanosheets are perpendicularly oriented on the surface of the graphene nanosheets. These MoSe2 nanosheet edges have a large number of electrochemically active sites, and the graphene sheets provide effective mass transportation of ions at the electrode–electrolyte interface. Cyclic voltammetry reveals the pseudocapacitive behaviour of a MoSe2/graphene nanohybrid based electrode. From galvanostatic charge–discharge studies, the specific capacitance is found to be 945 F g?1 at a current density of 1 A g?1. An asymmetric supercapacitor (ASC) device is fabricated, which delivers a specific capacitance of 75 F g?1 (@1 A g?1) with an energy density of 26.6 W h kg?1 and a power density of 0.8 kW kg?1, and it retains 88% of its capacitance even after 3000 cycles.
关键词： MoSe2,asymmetric supercapacitor,sonochemical synthesis,graphene,nanohybrid,electrochemical performance
更新于2025-09-19 17:15:36
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Successes and Issues in the Growth of Moad and MoSe2 on Ag(111) by the E-ALD Method
摘要： This paper explores the conditions for the electrodeposition of Moad (molybdenum adlayer) on Ag(111) from alkaline aqueous solution. Moreover, the first stages of the growth of MoSe2 are also presented, performing the deposition of Sead on the deposited Moad. The deposition of Moad on Sead/Ag(111) was also explored. MoSe2 is of interest due to its peculiar optoelectronic properties, making it suitable for solar energy conversion and nanoelectronics. In this study, electrodeposition techniques were exploited for the synthesis process as more sustainable alternatives to vacuum based techniques. The electrochemical atomic layer deposition (E-ALD) method emerges as a suitable technique to grow inorganic semiconductor thin films thanks to its fulfillment of the green energy predicament and a strict structural and morphological control, and this approach has gathered the attention of the scientific community. Indeed, E-ALD exploits surface limited reactions (SLRs) to alternate the deposition of chemically different atomic layers constituting a compound semiconductor. Thus, E-ALD is one of the most promising electrodeposition techniques for the growth of thin-film of compound semiconductors under a strict structural and morphological control. On this ground, E-ALD can be considered an ideal technique for the growth of 2D materials.
关键词： 2D materials,MoSe2,nanoelectronics,E-ALD
更新于2025-09-19 17:15:36