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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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Hydrogen Plasma–Treated MoSe2 Nanosheets Enhance the Efficiency and Stability of Organic Photovoltaics
摘要： In this paper we report the effect on the power conversion efficiency (PCE) and stability of photovoltaic devices after incorporating hydrogenated two-dimensional (2D) MoSe2 nanosheets into the active layer of bulk heterojunction (BHJ) organic photovoltaics (OPV). The surface properties of 2D MoSe2 nanosheets largely affect their dispersion in the active layer blend and, thus, influence the carrier mobility, PCE, and stability of corresponding devices. We treated MoSe2 nanosheets with hydrogen plasma and investigated their influence on the polymer packing and fullerene domain size of the active layer. For the optimized devices incorporating 37.5 wt% of untreated MoSe2, we obtained a champion PCE of 9.82%, compared with the champion reference PCE of approximately 9%. After incorporating the hydrogen plasma–treated MoSe2 nanosheets, we achieved a champion PCE of 10.44%—a relative increase of 16% over that of the reference device prepared without MoSe2 nanosheets. This PCE is the one of the highest ever reported for OPVs incorporating 2D materials. We attribute this large enhancement to the enhanced exciton generation and dissociation at the MoSe2–fullerene interface and, consequently, the balanced charge carrier mobility. The device incorporating the MoSe2 nanosheets maintained 70% of its initial PCE after heat-treatment at 100 °C for 1 h; in contrast, the PCE of the reference device decreased to 60% of its initial value—a relative increase in stability of 17% after incorporating these nanosheets. We also incorporated MoSe2 nanosheets (both with and without treatment) into a polymer donor (PBDTTBO)/small molecule (IT-4F) acceptor system. The champion PCEs reached 7.85 and 8.13% for the devices incorporating the MoSe2 nanosheets with and without plasma treatment, respectively—relative increases of 8 and 12%, respectively, over that of the reference. These results should encourage a push toward the implementation of transition metal dichalcogenides to enhance the performances of BHJ OPVs.
关键词： hydrogen plasma treatment,organic photovoltaics,stability,MoSe2 nanosheets,power conversion efficiency
更新于2025-09-11 14:15:04
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TiO2 nanoparticles modified with 2D MoSe2 for enhanced photocatalytic activity on hydrogen evolution
摘要： As an emerging two-dimensional (2D) nanomaterial, 2D MoSe2 nanosheets has the advantages of wide light response and rapid charge migration ability. In this work, 2D MoSe2/TiO2 nanocomposites were successfully synthesized through a simple hydrothermal method. The microstructure and photocatalytic activity of the nanocomposites were systematically investigated and determined. The corresponding Raman peaks and crystal planes of MoSe2 were analysed by Raman spectroscopy and transmission electron microscopy respectively, demonstrating the successful combination of the MoSe2 nanosheets and TiO2 nanoparticles. UV-vis diffused re?ectance spectra demonstrated that the introduction of MoSe2 did increase the light absorption ability of the nanocomposites. A lower recombination of electrons and holes was demonstrated for the MoSe2/TiO2 heterojunction from photoluminescence results. The photocatalytic hydrogen evolution test showed that the hydrogen production rate was 4.9 mmol h?1 for the sample with 0.1 wt.% MoSe2, 2 times higher than that of bare TiO2. This work provides a novel strategy for improving the photocatalytic properties of semiconductor photocatalyst.
关键词： Water splitting,MoSe2 nanosheets,Two dimensional,Photocatalysis,TiO2
更新于2025-09-10 09:29:36