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g-C3N4 nanosheets functionalized silicon nanowires hybrid photocathode for efficient visible light induced photoelectrochemical water reduction
摘要： We report the fabrication of hybrid Si nanowires @ g-C3N4 nanosheets based photocathode using metal assisted chemical etching and facile liquid exfoliated process. The g-C3N4 nanosheets on Si nanowires form hybrid heterojunction photocathode, which exhibits an enhanced photon induced water reduction activity enabling higher photocurrent density of 22 mA cm?2 with applied bias photocurrent conversion efficiency of 4.3% under visible light irradiation. The onset potential of cathodic photocurrent is positively shifted from 41 to 420 mV vs. RHE with the short circuit current density, Jsc of 0.50 mA cm?2 owing to superior charge transport in hybrid photocathode as compared to pristine Si nanowires for hydrogen evolving reaction at pH～7. The electrochemical impedance spectroscopy measurement elucidates the interface layer of g-C3N4 nanosheets form hybrid heterojunction with Si nanowires that result significant increment in solar water reduction activity owing to low charge transferred resistance with high life time of excited electrons in conduction band. This strategy may open to design a new low cost stable hybrid heterostructure photocathode for solar induced water reduction.
关键词： Solar water reduction,Si nanowires,Photocathode,g-C3N4 nanosheets,Interface
更新于2025-11-21 11:01:37
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Plasmonic nickel nanoparticles decorated on to LaFeO3 photocathode for enhanced solar hydrogen generation
摘要： Plasmonic Ni nanoparticles were incorporated into LaFeO3 photocathode (LFO-Ni) to excite the surface plasmon resonances (SPR) for enhanced light harvesting for enhancing the photoelectrochemical (PEC) hydrogen evolution reaction. The nanostructured LFO photocathode was prepared by spray pyrolysis method and Ni nanoparticles were incorporated on to the photocathode by spin coating technique. The LFO-Ni photocathode demonstrated strong optical absorption and higher current density where the untreated LFO film exhibited a maximum photocurrent of 0.036 mA/cm2 at 0.6 V vs RHE, and when incorporating 2.84 mmol Ni nanoparticles the photocurrent density reached a maximum of 0.066 mA/cm2 at 0.6 V vs RHE due to the SPR effect. This subsequently led to enhanced hydrogen production, where more than double (2.64 times) the amount of hydrogen was generated compared to the untreated LFO photocathode. Ni nanoparticles were modelled using Finite Difference Time Domain (FDTD) analysis and the results showed optimal particle size in the range of 70e100 nm for Surface Plasmon Resonance (SPR) enhancement.
关键词： LaFeO3,Finite difference time domain,Surface plasmon resonance,Ni nanoparticle,Photocathode,Photoelectrochemical water splitting
更新于2025-10-22 19:40:53
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Benthic microbial fuel cell equipped with a photocatalytic Cu2O-coated cathode
摘要： In this study, a photocatalytic benthic microbial fuel cell was developed and the cell performance was tested. A photocathode was fabricated by electrodeposition of Cu2O photocatalysts on carbon felt; with a proper deposition time of 15 min, a photocathode with optimal Cu2O compactness and an average Cu2O particle size of 0.97 μm was fabricated and was then covered with an amorphous carbon thin layer. Photoelectrochemical test results prove the pronounced visible light response of the fabricated photocathode. Results show that the coating of carbon thin layer could protect the Cu2O from self-reduction and also improve the photoelectrochemical performance of Cu2O crystalline grains. The photo-benthic microbial fuel cell (BMFC) produces a maximum power density of 249.0 mW m ? 2 and 186.7 mW m?2 under light irradiation and in the dark, which is 17.8 and 13.3 times higher than the common BMFC using carbon felt cathode in parallel, demonstrating the catalytic and photocatalytic effect of the fabricated photocathode. Polarization and EIS results prove the decrease of internal resistance by using the photocathode. The fabricated photocathode could improve the oxygen reduction rate on the cathode side, thus reduce the internal resistance and enhance the BMFC performance.
关键词： Benthic microbial fuel cells,Photocathode,Nanostructured catalyst,Visible light,Cu2O
更新于2025-09-23 15:23:52
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The cost-effective deposition of ultra-thin titanium(IV) oxide passivating layers for improving photoelectrochemical activity of SnS electrodes
摘要： The structures of tin monosulfide (SnS) with the surface modified by ultrathin titanium(IV) oxide layers for potential photoinduced water splitting were successfully fabricated. SnS thin films were deposited onto glass/Mo substrates using high vacuum evaporation (HVE) method, and then a simple and cost-effective deposition-annealing cycling process was used to prepare titanium(IV) oxide passivated SnS structures. The resulting compositional properties were studied using X-ray diffractometry (XRD), Raman spectroscopy, high resolution scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The effects of titanium(IV) oxide layers on the photo-electrochemical (PEC) activity of fabricated p-type SnS thin-film electrodes were examined in this study. The SnS layers passivated with titanium(IV) oxide exhibited reducing the SnS-electrolyte interface resistance, increasing the photocurrent and improving the efficiency of PEC cells as deleterious reactions are inhibited. The various electrochemical methods such as current-voltage measurements, cyclic voltammetry, and electrochemical impedance spectroscopy were used to characterise and analyse SnS structures modified by titanium(IV) oxide.
关键词： Photocathode,Solar energy,Tin sulfide,Titanium dioxide,Water splitting
更新于2025-09-23 15:22:29
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Optimized chemical cleaning procedure for enhancing photoemission from GaAs photocathode
摘要： To obtain cleaner GaAs photocathode surface, various wet chemical cleaning methods to remove the oxides and carbon contaminations from the surface of GaAs photocathode are investigated, and an improved chemical etching method is presented to further enhance the cathode photoemission performance. By means of X-ray photoelectron spectroscopy analysis, characteristics of these methods are summarized. HF solution can effectively reduce surface oxides, but it does not effectively act on the absorbed carbon contaminations. The mixed solution of HCl and isopropanol scores well in removing carbon contaminations, but the ability of removing oxides is relatively weaker. The mixed solution of HCl and deionized water right after the mixed solution of H2SO4, H2O2 and deionized water is unfavorable to reduce Ga oxides. The improved chemical etching method, which uses HF solution followed by the mixture of HCl and isopropanol has more advantages in removing oxides and carbon contaminations at the same time. Moreover, a hydrophobic surface is obtained by using the improved method, which also plays a role in the contaminations removal. The quantum efficiencies of GaAs photocathode undergoing various wet chemical cleaning procedures are compared after subsequent heat treatment and activation. The results show that the chemical treatment of HF solution followed by the mixture of HCl and isopropanol can help GaAs photocathode obtain higher activated photocurrent and quantum efficiency.
关键词： Chemical cleaning,GaAs photocathode,Quantum efficiency,X-ray photoelectron spectroscopy
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Coherent pulse beam in spin-polarized TEM using an NEA photocathode
摘要： Pulse beam emission in a spin-polarized pulse-TEM (SP-TEM) was performed using a combination of a semiconductor photocathode and an ultra-short pulse laser, which has an ability of a time-resolved measurement. The photocathode has high quantum efficiency of the order of 10-3 comparing with other metal-type photocathode, which can realize a wide range of the pulse duration from a continuous emission to a pico-second pulse emission. The SP-TEM has several advantages of a high brightness of 3.1×108 A cm-2 sr-1, a narrow energy width of 114meV and a long coherence length of 200 nm in a continuous mode. Time-resolved TEM image and pulsed interference fringes were also conducted successfully with a stroboscopic technique. Consequently, instead of a high current density, the pulsed electron beam emitted from the photocathode has enough coherence to realize a time-resolved holography that can observe phase information in a temporal space.
关键词： coherent,photocathode,pulse,electron microscope
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Study on Photoemission of Patterned Carbon Nanotubes Modified with Gold Nanoparticles
摘要： Employing the edge effect and localized surface plasmon resonance effect, an enhanced photoemission is obtained from a carbon nanotube (CNT) arrays modified with gold nanoparticles. Compared with the unpatterned CNTs, the quantum efficiency of patterned CNTs is improved from 3.69×10-6 to 1.85×10-5. After modification with gold nanoparticles, the quantum efficiency of patterned CNTs is further raised to 4.98×10-5. This work makes CNTs as a promising material for the high stability and high efficiency photocathode.
关键词： Patterning,Photocathode,Gold nanoparticles,CNTs
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - High-frequency photocathode based on CNT-yarn emitter and GaAs photoswitch
摘要： A high frequency photocathode based on a carbon nanotube (CNT)-yarn in series to a semi-insulating (s.i.) GaAs was fabricated and used for field electron emission in a diode configuration. This hybrid two-chip technology allows the separate optimization of the yarn emitter and the photoswitch. This concept can overcome the capacitance limitations of miniaturized high-frequency vacuum tubes. The used CNT yarn emitter with 20 μm diameter had a threshold electric fields of ~1.8 V/μm (defined at 1mA/cm2) with a stable field emitter current up to 400 μA. The high-voltage photomodulation was up to 100 MHz.
关键词： carbon nanotube,CNT yarn,photocathode,semi-insulating GaAs
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Bi-Alkali photocathode for a bunched electron beam
摘要： We have focused on Smith-Purcell superradiant (SPR) as one of the promising methods for THz wave generation. The ordinary SPR is a kind of spontaneous emission. SPR emits from an accelerated electron beam and an interactive metal circuit. Electric magnetic wave emits from the electric dipole oscillation and the output power is quite weak. In order to increase the radiation power, using a pre-bunched electron train beam has been proposed in our report. With pre-bunched electron beam, superradiant is expected. To realize superradiant, a cathode with a response time of less than 30 psec is required. In this study, an alkali photocathode which has a response time around several 10 picoseconds and high quantum efficiency more than 10% was adopted. We report on the fabrication of Sb-Cs and bi-alkali photocathode.
关键词： Smith Purcell superradiant,Alkali Photocathode
更新于2025-09-23 15:21:21
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Dual-photocathode array propelled lab-on-paper ratiometric photoelectrochemical sensing platform for ultrasensitive microRNA bioassay
摘要： In this work, a dual-photocathode array propelled lab-on-paper ratiometric photoelectrochemical (PEC) sensing platform integrated with DNA bridge nanostructure mediated electron-transfer tunneling distance regulation strategy was engineered for ultrasensitive assay of microRNA-141 (miRNA-141). Specifically, the spatial-resolved dual-photocathode array were comprised of a working electrode (PCE1) and internal reference electrode (PCE2), which were responsible for producing independent working signal (Iw) and internal reference signal (Ir). The dual-photocathode array was assembled with cascading multiple photosensitive structures enhanced rigidity remarkably increased the electron-transfer tunneling distance DNA probes from various concentrations of miRNA-141 induced duplex specific output DNA probes produced with a constant concentration of miRNA-141 were (NPs). With the proximity regulation of DNA hairpins H1 and H2, the amplified nanostructures on PCE1 and PCE2. Those formed DNA bridge nanostructures with consisting of pyramid-shaped Cu2O, graphene quantum dots, and AgI nanoparticles introduced onto PCE2, resulting in the formation of different amounts of DNA bridge photocurrent signals were obtained on PCE1 and PCE2. When target existed, the output nuclease-catalyzed target recycling reactions were introduced onto PCE1, while the Iw and constant Ir were ultimately collected. By monitoring the ratio of Iw and Ir, the different amounts of target-induced output DNA probes on PCE1 and PCE2, the variable between the sensing interface and AgI NPs immobilized on the terminals of H1 and H2, leading to noticeably decreased photocurrent signals. Based on the introduction of ultrasensitive bioassay of miRNA-141 was realized with high accuracy, selectivity, and practicability.
关键词： Pyramid-shaped Cu2O,Dual-photocathode array,DNA bridge nanostructure,Photoelectrochemical,Ratiometric
更新于2025-09-23 15:19:57