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The fabrication of graphene-polypyrrole composite for application with dye-sensitized solar cells
摘要： This research is to study the preparation of graphene-monodispersed polypyrrole composite materials for uses as a counter electrode in dye-sensitized solar cells (DSSCs). The preparation started with the synthesis of graphene oxide (GO), followed by the preparation of composite films by polymerization method and the GO reduction process by ascorbic acid. The characterizations included thermal-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR), raman spectroscopy, X-ray diffraction (XRD), field-emission electron microscopy (FESEM) and cyclic voltammetry (CV). The DSSCs’ efficiency tests were also conducted and analyzed. Based on the test results, it was found that DSSCs prepared from PPy/RGO-5 composite films with 5% by weight of reduced graphene oxide (RGO) could give an optimal efficiency. Nevertheless, the efficiency of such solar cells was much less than that of DSSCs with platinum counter electrode. This could be due to incomplete reduction of graphene oxide, resulting low electron transfer ability and electrocatalytic activity toward the reduction of electrolyte solution.
关键词： Reduced graphene oxide,Polypyrrole,Dye-sensitized solar cells,Counter electrode
更新于2025-09-16 10:30:52
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Screen printed tin selenide films used as the counter electrodes in dye sensitized solar cells
摘要： In this work, the scalable screen printing process has been adopted to prepare low-cost and earth-abundant tin selenide (SnSe) films to study as the counter electrode in dye-sensitized solar cells (DSSCs). The SnSe powder was synthesized by solid state reaction method and corresponding films were fabricated by screen printing technique. The electrocatalytic activity of SnSe for redox iodide/triiodide (I?/I3?) couple and charge transfer resistance at the CE/electrolyte interface were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The DSSC with SnSe counter electrode exhibited with power conversion efficiency (PCE) of ~5.76% with open-circuit voltage of 0.63 V and short circuit current density of 12.39 mA/cm2 whereas the DSSC with platinum counter electrode showed PCE of 8.09% with open-circuit voltage of 0.68 V and short circuit current density of 14.77 mA/cm2. Thus, earth abundant and low cost SnSe films fabricated by screen printing technique could be an alternative to costly platinum counter electrode in DSSC.
关键词： Counter electrode,SnSe films,DSSC,Chalcogenides,Screen printing
更新于2025-09-16 10:30:52
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Highly Efficient Flexible Perovskite Light-Emitting Diodes Using Modified PEDOT:PSS Hole Transport Layer and Polymer-Silver Nanowires Composite Electrode
摘要： Metal halide perovskites have been actively studied as promising materials in optoelectronic devices because of their superior optical and electrical properties, and have also shown considerable potential for flexible devices because of their good mechanical properties. However, the large hole injection barrier and exciton quenching between the perovskite emitter and poly(3,4-ethylenedioxythiophene):poly-styrene sulfonate (PEDOT:PSS) can lead to the reduction in device efficiency. Here, a nonconductive fluorosurfactant, Zonyl FS-300 (Zonyl), is introduced into the PEDOT:PSS hole transport layer, which reduces the hole injection barrier and exciton quenching at the PEDOT:PSS/perovskite interface. Moreover, a flexible perovskite light-emitting diode with a polymer–silver nanowire composite electrode is demonstrated, showing a maximum current efficiency (CEmax) of 17.90 cd A–1, and this is maintained even after 1,000 cycles of bending with a 2.5 mm bending radius.
关键词： flexible perovskite light-emitting diodes,hole transport layer,flexible electrode,silver nanowires (AgNWs),poly(3,4-ethylenedioxythiophene):poly-styrene sulfonate (PEDOT:PSS)
更新于2025-09-16 10:30:52
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Paper-Based Flexible Electrode Using Chemically-Modified Graphene and Functionalized Multiwalled Carbon Nanotube Composites for Electrophysiological Signal Sensing
摘要： Flexible paper-based physiological sensor electrodes were developed using chemically-modified graphene (CG) and carboxylic-functionalized multiwalled carbon nanotube composites (f@MWCNTs). A solvothermal process with additional treatment was conducted to synthesize CG and f@MWCNTs to make CG-f@MWCNT composites. The composite was sonicated in an appropriate solvent to make a uniform suspension, and then it was drop cast on a nylon membrane in a vacuum filter. A number of batches (0%~35% f@MWCNTs) were prepared to investigate the performance of the physical characteristics. The 25% f@MWCNT-loaded composite showed the best adhesion on the paper substrate. The surface topography and chemical bonding of the proposed CG-f@MWCNT electrodes were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The average sheet resistance of the 25% CG-f@MWCNT electrode was determined to be 75 ?/(cid:3), and it showed a skin contact impedance of 45.12 k? at 100 Hz. Electrocardiogram (ECG) signals were recorded from the chest and fingertips of healthy adults using the proposed electrodes. The CG-f@MWCNT electrodes demonstrated comfortability and a high sensitivity for electrocardiogram signal detection.
关键词： solvothermal-treated,flexible dry electrode,graphene-based composites,electrocardiogram,functionalized MWCNTs
更新于2025-09-16 10:30:52
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In-depth study of annealed porous silicon: Understand the morphological properties effect on negative LiB electrode performance
摘要： Silicon (Si) used as negative electrode in a Li-ion battery (LIB) is highly attractive for its high energy density, safe cycling, and nontoxicity. However its alloying mechanism with Li induces material pulverization, which leads to a rapid capacity fade. In this work, annealing post treatment was used in order to tune the morphological properties of porous silicon. Playing on annealing temperature, the morphological modification induces electrochemical behavior changes in LIB. The porosification is an interesting way to accommodate the volume expansion occurring during the alloying process. Increase of the annealing temperature leads to porous Si pores and walls reorganization, which has a positive impact on battery performance likely due to a higher wettability of the Si electrode with electrolyte. 700 °C appeared to be the optimized annealing temperature.
关键词： Negative electrode,Morphological properties,Li-ion battery,Annealing,Silicon,Electrochemical behavior,Porous silicon
更新于2025-09-16 10:30:52
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Surfactant mediated TiO2 photoanodes and Cu2ZnSnS4 counter electrodes for high efficient dye sensitized solar cells
摘要： Highly crystallized kesterite Cu2ZnSnS4 (CZTS) nanoparticles with an energy band gap of 1.54 eV and desired elemental compositions were prepared by hydrothermal method. CZTS thin films were prepared on titanium tetrachloride (TiCl4) treated fluorine doped tin oxide (FTO) substrate by doctor blade coating method. Morphological developments of hydrothermal synthesized, sodium dodecyl sulfate (SDS) mediated, TiO2 nanostructured thin films on TiCl4 treated FTO substrate were investigated. The CZTS/FTO counter electrodes (CSs) and TiO2 nanostructured photoanodes were employed in dye sensitized solar cells (DSSCs). DSSCs device with power conversion efficiency of 6.24% have been fabricated. The TiCl4 treated CZTS CEs and SDS mediated TiO2 nanostructure photoanodes provides suitable electrodes for low cost and high efficient dye sensitized solar cells.
关键词： Thin films,CZTS counter electrode,Energy storage and conversion,Nanocrystalline materials,Dye sensitized solar cell
更新于2025-09-16 10:30:52
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Bimetallic PtSe nanoparticles incorporating with reduced graphene oxide as efficient and durable electrode materials for liquid-junction photovoltaic devices
摘要： In this work, we introduce the synthesis of PtSe alloys with the different stoichiometric ratio of Pt and Se in PtSe alloy on reduced graphene oxide (RGO). And, then the developed nanohybrid materials are employed for the first time as counter electrodes (CEs) for efficient third-generation solar cells. As a result, PtSe nanoalloys is located on the surface of RGO without any agglomerations. Furthermore, the developed materials also provide a porous three-dimensional network structure, suggesting rapid electron transfer paths. Therefore, the highest efficiency of 6.26% was obtained for a cell fabricated with Pt0$74Se0.26/RGO electrode that is due to the lowest charge-transfer resistance of 0.89 U and diffusion impedance of 0.88 U. The optimized efficiency is also higher than those of 4.98% and 4.34% for devices assembled with Pt/RGO and Se/RGO CEs, respectively. This work presents a general strategy for designing and fabricating porous PtSe alloy/RGO CEs for energy conversion devices.
关键词： PtSe/graphene,Hybrid materials,Counter electrode,Dye-sensitized solar cells
更新于2025-09-16 10:30:52
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A brief introduction to the selective laser melting of Ti6Al4V powders by supreme-speed plasma rotating electrode process
摘要： In the present study, Ti6Al4V spherical powders were prepared by supreme-speed plasma rotating electrode process and the particle size fit log-normal distribution. The average diameter of the powders was successfully determined by a model developed in this work, suggesting that the particle size distribution is mainly affected by the rotating speed. The log-normal distribution factor of the particle size distribution maintains stable as the rotating speed ω varies. The particle size distribution indicates that the main atomization mode of Ti6Al4V under supreme-speed plasma rotating electrode process is of the characteristics of direct drop formation. The mechanical properties of the samples prepared by selective laser melting of Ti6Al4V powders were characterized, indicating that such Ti6Al4V samples with isotropy structure exhibit high yield strength and good ductility.
关键词： Atomization,Ti6Al4V,Selective laser melting,Rapid solidification,Particle size distribution,Plasma rotating electrode process
更新于2025-09-16 10:30:52
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Fabricating Strongly Coupled V2O5@PEDOT Nanobelts/Graphene Hybrid Films with High Areal Capacitance and Facile Transferability for Transparent Solid-State Supercapacitors
摘要： Transparent energy-storage devices are of enormous significance to the continued growth of flexible and wearable electronics in the foreseeable future. The development of transparent supercapacitive electrodes that possess not only high optical transmittance but also intriguing features of energy-storage capability, transferability and outstanding durability, remains a remarkable challenge. Here we demonstrate a polymer-glued strategy to fabricate the conjugated transparent hybrids of V2O5 and graphene, whereby the poly(3,4-ethylenedioxythiophene) (PEDOT) forms a conformal coating on the surface of V2O5 nanobelts and functions as a glue. Interestingly, the PEDOT-glued V2O5/graphene (VP-G) is easy-transferrable onto various flat and even curved substrates. When served as a transparent supercapacitive electrode, the VP-G exhibits a high areal capacitance of 22.4 mF cm?2 at an optical transparency of 70%. As unveiled by experimental results and density functional theory (DFT) calculations, both the kinetic blocking of the PEDOT layer and the anchoring capability of graphene upon soluble vanadium ions contribute synergistically to the unusual electrochemical stability. Transparent, high-energy-density solid-state supercapacitors made of the as-fabricated hybrids are constructed, exhibiting a high energy density of 0.18 μWh cm?2 at 11 μW cm?2. As expected, the constructed transparent supercapacitors demonstrate an excellent cycling stability over 50 000 cycles with capacitance retention of 92.4%. These results show its great potential as promising transparent devices.
关键词： transparent supercapacitors,high stability,high areal capacitance,strongly coupled nanocompsites,transferable electrode
更新于2025-09-16 10:30:52
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Ni3S2@MWCNTs films for effective counter electrodes of dye-sensitized solar cells
摘要： Composite films nickel sulfide (Ni3S2) nanoparticles were grown on multiwall carbon nanotubes (MWCNTs) and in situ coated onto conducting glass substrates by the hydrothermal process at 170 °C. These Ni3S2@MWCNTs films were applied for counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). In this work, nanostructure, crystalline structure, electrochemical activities and electron-charge transfer resistance of CEs were studied. In addition, the effective surface areas of CEs were analyzed and discussed as well. The power conversion efficiency (PCE) enhancement of up to 7.48%, compared with that of Ni3S2-DSSC, was demonstrated for a Ni3S2@MWCNTs DSSC.
关键词： Counter electrode,Ni3S2,Dye-sensitized solar cell,Hydrothermal method,Multiwall carbon nanotubes
更新于2025-09-16 10:30:52