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Metala??organic framework nanosheets for enhanced performance of organic photovoltaic cells
摘要： Metal-organic nanosheets (MONs) are an emerging class of two-dimensional materials whose diverse and readily tunable structures make them ideal for use in optoelectronic applications. Here, liquid exfoliation is used to synthesize ultrathin zinc-porphyrin based MONs with electronic and optical properties ideally suited for incorporation into a polythiophene-fullerene (P3HT-PCBM) organic solar cell. Remarkably, the addition of MONs to the photoactive layer of a photovoltaic device results in a power conversion efficiency of 5.2%, almost twice that for reference devices without nanosheets with a simultaneous improvement of Jsc, Voc and FF. Our analysis indicates that the complimentary electronic, optical and structural properties of the MONs allows them to act as a surface to template the crystallization of P3HT leading to a doubling of the absorbance, a tenfold increase in hole mobility and reduced grain size. These results demonstrate the potential of MONs as a tunable class of two-dimensional materials for enhancing the performance of a broad range of organic solar cells and other electronic devices.
关键词： Metal-organic nanosheets,organic photovoltaic cells,power conversion efficiency,liquid exfoliation,zinc-porphyrin
更新于2025-09-19 17:13:59
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Heating Rate-Controlled Thermal Exfoliation for Foldable Graphene Sponge
摘要： Foldable supercapacitors are desired for the next generation of wearable electronics. In this study, highly foldable graphene sponges with a honeycomb structure are prepared at 300 °C using the convenient thermal exfoliation process. A slow heating rate (5?10 °C·min?1) around 200 °C and an external con?nement force are critical to a favorable exfoliation degree and uniform thickness of the graphene sponges. After being annealed at 1050 °C for 1 h, the conductivity of the graphene sponge has been improved from 2700 to 6900 S·m?1 without degrading its ?exibility. The capacitance of the annealed graphene sponge has been measured in an aqueous electrolyte solution of 1 M Na2SO4. Its best capacitance is 138.74 F·g?1, and it reduces by 3.6% at a half-fold state and by 8.9% at a quarter-fold state.
关键词： wearable electronics,Foldable supercapacitors,honeycomb structure,thermal exfoliation,graphene sponges
更新于2025-09-19 17:13:59
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Size-controlled MoS<sub>2 </sub>nanosheet through ball milling exfoliation: parameter optimization, structural characterization and electrocatalytic application
摘要： Unique properties and potential applications of 2D materials draw much attention for mass production of thin-layer 2D materials. Ball milling exfoliation of 2D materials has been rarely used, in spite of a promising dry phase production method, because of the superficial information in the mechanism and the effect of the operating parameters on the yield, size and thickness. Here, we investigate systematically the ball milling operating parameters in the exfoliation of bulk MoS2 in the presence of sodium cholate (SC) as an exfoliant. The yield and dimensions of the exfoliated MoS2 nanosheet were monitored by changing the parameters such as the weight ratio of bulk MoS2 and SC (SC/MoS2), the filling ratio in the volume of milling ball and container (!), milling ball size (dB), milling revolution speed (nR), and initial mass of bulk MoS2 (mMoS2). The yield of exfoliation is found to be 95% at the optimum ball milling conditions (SC/MoS2 = 0.75, ! = 50%, mMoS2 = 0.20 g). In addition, yield and size of the exfoliated MoS2 were controlled by the conditions of the ball milling. As for the evaluation of size and thickness of the ball-milled MoS2 powder with less than 30% difference from those determined by the well-known absorption method. Finally, the size and thickness of the MoS2 nanosheets prepared by ball milling exfoliation were correlated with their electrocatalytic and photoelectrocatalytic activities.
关键词： electrocatalyst,sodium cholate,nanosheet,exfoliation,Ball milling,molybdenum disulfide,XRD
更新于2025-09-19 17:13:59
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Facile large-scaled fabrication of graphene-like materials by ultrasonic assisted shear exfoliation method for enhanced performance on flexible supercapacitor applications
摘要： In this work, we have developed a rapid and simple approach for fabrication of graphene-like materials. It consisted of shearing commercial graphite in aqueous solution with the assistance of ultrasonication. The results showed that the graphene-like materials were successfully fabricated with not only similar flake structure of graphene, but also improved conductivity. For the applications of flexible supercapacitors, the as-prepared graphene-like materials showed better specific capacitance than commercial graphite as the working electrode. In addition, the rate capability of the flexible supercapacitor device is 80% and the capacitance retention reaches 90% after 10,000 cycles. The high flexibility of the as-fabricated graphene-like materials gives rise to high flexibility of all-solid-state supercapacitors, and the specific capacitance was not affected by bending state. The as-fabricated supercapacitor further demonstrated that it can drive the resistive pressure sensor and the voltage was stable at a fixed value under different values of pressure.
关键词： Graphene-like structure,Ultrasonic assisted shear exfoliation,Supercapacitor/resistive pressure sensor hybrids,Flexible supercapacitor
更新于2025-09-19 17:13:59
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Transferrable thin film of ultrasonically exfoliated MoSe2 nanocrystals for efficient visible-light photodetector
摘要： Two-dimensional transition metal dichalcogenides (2D TMDC’s) materials are the impactful candidates in nanotechnology for diverse applications such as electrocatalyst, sensing and energy storage. Many efforts have been accomplished to solve the problem of green production with the scaling of TMDCs materials. Here we demonstrated the two-step method including electrophoresis deposition (EPD) and direct transfer of MoSe2 nanocrystals (NCs) thin film for fabricating visible-light photodetector. High-resolution transmission electron microscopy and atomic force microscopy show that the liquid exfoliated MoSe2 NCs exhibits good crystalline nature with multi-layered thickness. Raman spectra, UV-Visible spectra, and X-ray photoelectron spectroscopy confirm the presence of 2H-phase of MoSe2 NCs. EPD deposited thin film is detached by dipping into the water and transferred onto the etched ITO substrate. Ag/MoSe2 NCs/ITO photodetector is fabricated which demonstrated the excellent performance in the visible range and demonstrate remarkable values of responsivity, EQE (%) and specific detectivity of 566 mAW-1, 155 % and 3.69 × 1011 Jones. Considering our results, the fabrication technique along with the photoresponse application of TMDC NCs presented here is the innovative and efficient way for developing the large-area optoelectronic devices.
关键词： MoSe2 nanocrystals,Liquid-phase exfoliation,Electrophoresis,Visible-light photodetector
更新于2025-09-19 17:13:59
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Photovoltaic activity of WSe2/Si hetero junction
摘要： Propelled by the development of layered transition metal dichalcogenides, heterojunctions have captivated tremendous attention due to various excitonic mechanisms assisted strong light-matter interaction. We demonstrate liquid phase exfoliation of WSe2 and fabrication of fast switchable WSe2/Si heterojunction. The heterojunction device showed obvious rectifying nature with ideality factor of 1.21 and it is explored under white illumination at power intensities varying from 5 to 18 mW/cm2. The WSe2/Si heterojunction photovoltaic device exhibited excellent transient photoresponse with highest responsivity of 86.11 mA/W and 23 ms response time under white light. Besides, heterojunction exhibited excellent photoresponse in broad spectral range from 390 to 1088 nm with highest photoresponsivity of 122.2 mA/W for 780 nm illumination. The device showed excellent response in temperature range 200 to 300 K. Eventually, the results advocate the huge significance of WSe2/Si heterojunction for photovoltaic cell and photodetection.
关键词： WSe2/Si heterojunction,Responsivity,Liquid phase exfoliation,Photovoltaic activity,Morse codes
更新于2025-09-16 10:30:52
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Random nanohole arrays and its application to crystalline Si thin foils produced by proton induced exfoliation for solar cells
摘要： We report high efficiency cell processing technologies for the ultra-thin Si solar cells based on crystalline Si thin foils (below a 50 μm thickness) produced by the proton implant exfoliation (PIE) technique. Shallow textures of submicrometer scale is essential for effective light trapping in crystalline Si thin foil based solar cells. In this study, we report the fabrication process of random Si nanohole arrays of ellipsoids by a facile way using low melting point metal nanoparticles of indium which were vacuum-deposited and dewetted spontaneously at room temperature. Combination of dry and wet etch processes with indium nanoparticles as etch masks enables the fabrication of random Si nanohole arrays of an ellipsoidal shape. The optimized etching processes led to effective light trapping nanostructures comparable to conventional micro-pyramids. We also developed the laser fired contact (LFC) process especially suitable for crystalline Si thin foil based PERC solar cells. The laser processing parameters were optimized to obtain a shallow LFC contact in conjunction with a low contact resistance. Lastly, we applied the random Si nanohole arrays and the LFC process to the crystalline Si thin foils (a 48 μm thickness) produced by the PIE technique and achieved the best efficiency of 17.1% while the planar PERC solar cell without the Si nanohole arrays exhibit 15.6%. Also, we demonstrate the ultra-thin wafer is bendable to have a 16 mm critical bending radius.
关键词： proton implant exfoliation,random Si nanohole arrays,PERC solar cells,ultra-thin Si solar cells,light trapping,laser fired contact
更新于2025-09-16 10:30:52
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Exfoliated MXene as a mediator for efficient laser desorption/ionization mass spectrometry analysis of various analytes
摘要： The exfoliated MXene (e-MXene) is systematically investigated as a mediator for laser desorption/ionization time-of-flight mass spectrometry (LDI-MS) analysis. Whereas un-exfoliated MXene has no activity for LDI-MS analysis, the e-MXene presents a high resolution, salt-tolerance and efficiency for LDI-MS analysis of various small molecules regardless of their polarity, aromaticity and molecular weight owing to its physicochemical properties such as high laser energy absorption, electrical conductivity and photothermal conversion. Based on our findings, it is clearly confirmed that e-MXene is a promising material for the development of an efficient platform for LDI-MS analysis of small molecules.
关键词： Metabolite,MXene,Mass spectrometry,Laser desorption ionization,Exfoliation
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Femtosecond Laser-assisted Fabrication of Fluorescent Boron Nitride Quantum Dots
摘要： As a kind of heavy metal-free quantum dot, boron nitride quantum dots (BNQDs) have attracted great interest due to their unique optical properties. Although there many synthesis methods of BNQDs, most of them require complex or time-consuming procedures, which limits the application of BNQDs. Here, we present a facile synthesizing method of few-layer BNQDs, which is based on liquid-phase ultra-short laser pulse ablation and ultrasonic-assisted exfoliation methods. The fabricated BNQDs are systematically characterized by atomic force microscope, transmission electron microscope, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The products possess an average size of about 2.1 nm with few-layer thickness. Because of the abundant surface functional groups, the BNQDs show bright luminescence emission under UV light irradiation.
关键词： femtosecond laser pulse ablation,ultrasonic-assisted exfoliation,boron nitride quantum dots
更新于2025-09-16 10:30:52
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Facile Preparation of Molybdenum Disulfide Quantum Dots Using a Femtosecond Laser
摘要： Molybdenum disulfide (MoS2) is rapidly emerging in a wide range of applications owing to its superior optical, electrical, and catalytic properties. In particular, aside from the current great interest in monolayer MoS2, MoS2 quantum dots (QDs) have received much attention in the electronics and optoelectronics fields owing to their inherent electrical and optical properties arising from the quantum confinement effect. Thus, various methods for producing MoS2 QDs, such as exfoliation, substrate growth, and colloidal synthesis, have been attempted. In this study, the method for manufacturing MoS2 QD with a size of 10 nm which is simpler than the conventional method was devised. On the basis of characterization of the prepared MoS2 QD samples, resistive switching devices was fabricated. These devices demonstrated stable unipolar resistive switching behavior without an electroforming process. This study provides a new approach for the mass production of MoS2 QD and one of their potential applications.
关键词： exfoliation,memristor,MoS2,quantum confinement effect,phase transition
更新于2025-09-16 10:30:52