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- 2018
- imgae sensor
- internet of things
- drone
- visible light ID
- Signal-to-Noise Ratio (SNR)
- Infinite Gain Multiple Feedback (IGMF)
- Visible Light Communications (VLC)
- LED
- Trans-Impedance Amplifier (TIA)
- Optoelectronic Information Science and Engineering
- Tohoku University
- University of Northumbria
- University of Huddersfield
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Phthalocyanine Zinc‐catalyzed Hydroxylation of Aryl Boronic Acids under visible Light
摘要： A visible-light-promoted aerobic oxidative hydroxylation of boronic acids using phthalocyanine zinc as an easily available photosensitizer has been developed. It provided a direct access to synthesize aliphatic alcohols and phenols from boronic acids. The advantages of this approach included the low catalyst loading (0.5 mol %), high efficient, the use of O2 as an oxygen source, wide substrate range, the simple operational process, and mild conditions.
关键词： phenols,phthalocyanine zinc,visible light,boronic acids,aerobic oxidative hydroxylation
更新于2025-09-04 15:30:14
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Enhancing the Secrecy Performance of the Spatial Modulation Aided VLC Systems with Optical Jamming
摘要： In order to enhance the secrecy performance of the spatial modulation (SM) aided visible light communication (VLC) system, an optical jamming aided secrecy enhancement scheme is proposed in this paper, in which transmitter (Alice) sends the optical jamming signals and the con?dential signals simultaneously with amplitude and power constraints, wherein the truncated Gaussian distribution is adopted by the optical jamming signals for the considered constraints. Additionally, with ?nite discrete support set of the channel inputs’ distribution, the corresponding secrecy performance is systematically analyzed for the optical jamming aided SM-VLC system, which includes the average mutual information (AMI), the lower bound on AMI and its closed-form expression approximation and the achievable secrecy rate. Furthermore, the power allocation problem for the proposed SM-VLC systems with optical jamming is considered. Finally, extensive simulation results are presented to validate our analytical results and the secrecy versus bit error ratio (BER) trade-off is characterized.
关键词： physical layer security (PLS),Visible light communication (VLC),spatial modulation (SM),power allocation,achievable secrecy rate,optical jamming
更新于2025-09-04 15:30:14
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Cascade electronic band structured zinc oxide/ bismuth vanadate/ three-dimensional ordered macroporous titanium dioxide ternary nanocomposites for enhanced visible light photocatalysis
摘要： Ternary zinc oxide/ bismuth vanadate/ three-dimensional ordered macroporous titanium dioxide (ZnO/BiVO4/3DOM TiO2) heterojuncted nanocomposites with cascade electronic band structures were successfully designed and synthesized for visible light photodegradation of two different molecules: Rhodamine B (RhB) and Tartrazine. The photocatalytic active species have been investigated by using electron scavenger (AgNO3) and hole scavenger (Triethanolamine: TEOA). The band edge positions of each component in tenary nanocomposites have been measured by using photoelectrochemical Mott-Schottky method and valence band XPS (VB-XPS) spectroscopy. Within the heterojunction, charges are favorably and spatially separated through the gradient potential at the interfaces. This largely suppresses the recombination of photogenerated electrons and holes. Furthermore, 3DOM inverse opal structure is beneficial for high diffusion efficiency and highly accessible surface area of reactants and light and multiple scattering for light harvesting. Consequently, these heterojuncted nanocomposites exhibit highly enhanced photocatalytic performance compared with pure BiVO4 nanostructure, and binary BiVO4/3DOM TiO2, ZnO/BiVO4 nanocomposites. A detailed mechanism of charge transfer is proposed for these ternary ZnO/BiVO4/3DOM TiO2 nanocomposites on the basis of a large series of spectroscopic and photocatalytic results. Our work demonstrates clearly that coupling multicomponent semiconductors with different energy levels of conduction and valence bands can significantly increase the photogenerated charge carriers through the efficient charge separation across their multiple interfaces. This work gives some new ideas on developing new visible light responsive nanocomposites for highly efficient solar energy utilization.
关键词： visible light,RhB and Tartrazine,Ternary ZnO/BiVO4/3DOM TiO2 nanocomposites,photogenerated electron–hole pairs,heterojunction structures
更新于2025-09-04 15:30:14
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Tetrathiafulvalene Scaffolds Based Sensitizer on Hierarchical Porous TiO <sub/>2</sub> : Efficient Light Harvesting Material for Hydrogen Production
摘要： In this work, a photochemical device that contains thioalkyl substituted tetrathiafulvalene dyes and hierarchical porous TiO2, has been designed and successfully employed in visible light-driven hydrogen production. The design strategy boost up the desirable photophysical properties of the catalysts and well supported from the optical, electrochemical and computational studies. The introduction of thioalkyl substituted tetrathiafulvalene dyes as light harvesting sensitizers onto the porous TiO2 triggers unprecedented high rate of hydrogen evolution. This study focuses on the role of thiafulvalene scaffold which can promote ultrafast interfacial electron injection from excited state dye into the hierarchical porous TiO2 conduction band. The purposeful construction of this integrated composite G3T3 (dye content 1.0 μmol in 10 mg Pt-TiO2 composite) significantly increases the hydrogen production rate of 24560 μmol.h-1g-1 cat with high apparent quantum yield (AQY) ~ 41%. In the study, both sensitizers absorption onset extends up to 500 nm in solution and 600 nm on hierarchical porous TiO2. Density functional theory (DFT) in the present study described that the HOMO levels are delocalized on anthracene as well as tetrathiafulvalene donor units, and LUMO covers on to the carboxylate anchoring group in both dyes. This study unveiled first time that a tetrathiafulvalene scaffolds in porous TiO2 attributes to positive synergistic effects in hydrogen production.
关键词： Tetrathiafulvalene,Hydrogen Production,Photocatalysis,Hierarchical Porous TiO2,Visible Light
更新于2025-09-04 15:30:14
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Selective Ferroelectric BiOI/Bi4Ti3O12 Heterostructures For Visible-light-driven Photocatalysis
摘要： Ferroelectric-photocatalyst/photocatalyst heterojunctions have very attractive photocatalytic activities. Beside enhanced charge carrier separation due to their internal electric fields, charge transfer could be even further enhanced by designing the heterojunction interface. In this work, the polarization-adsorption interaction that exists in ferroelectric materials was employed for successful deposition of BiOI on specific surfaces of Bi4Ti3O12 plates in the dark at room temperature, where the positively polarized region was found. The crystal structure, morphology, and composition of samples were confirmed by X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. Higher photocatalytic activity was achieved by the use of heterojunctions, with the reason behind the enhancement of activity confirmed to be the modified band structure, which contributed to the transfer of photoelectrons from Bi4Ti3O12 to BiOI, the increased visible light absorption, the increased active site area of positively polarized Bi4Ti3O12, and the elimination of the screening layer, which contributes impedance in charge transfer.
关键词： Visible-light-driven,Photocatalysis,Heterostructures,BiOI/Bi4Ti3O12,Ferroelectric
更新于2025-09-04 15:30:14
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Magnetically Recyclable MoS <sub/>2</sub> /Fe <sub/>3</sub> O <sub/>4</sub> Hybrid Composite as Visible Light Responsive Photocatalyst with Enhanced Photocatalytic Performance
摘要： Photocatalysis is one of the most promising technologies in wastewater treatment. However, the inactivity to visible light and the inconvenience to recycle severely limit its practical application. In this work, via a facile hydrothermal method, Fe3O4 NPs were integrated onto the surfaces of 3D ball-flower-like MoS2 microspheres as efficiently visible light responsive and magnetically recyclable photocatalysts. Experimental results indicate that, an optimal loading amount (20 wt.%) of Fe3O4 NPs can not only effectively enhance the photocatalytic ability of the MoS2/Fe3O4 (MF) hybrid composite with approximately 2 times better than pure MoS2, but also make it conveniently recycle from water by an external magnetic field. The photoelectrochemical studies also reveal that the incorporation of Fe3O4 NPs can effectively enhance the charge transfer rate and accelerate separation of photo-induced charge carriers. The surface catalytic mechanism of MF hybrid composite was also explored through XPS spectra. With both the excellent photocatalytic performance and magnetical recyclability, the 20wt%-MF hybrid composite is considered to be a promising and competitive photocatalyst for wastewater treatment utilizing solar energy.
关键词： magnetical recyclability,Fe3O4 NPs,MoS2,photocatalyst,visible light responsive
更新于2025-09-04 15:30:14
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Visible light thiocyanation of <i>N</i> -bearing aromatic and heteroaromatic compounds using Ag/TiO <sub/>2</sub> nanotube photocatalyst
摘要： In this study, Ag/TiO2 nanotubes (Ag/TNT) were synthesized via simple hydrothermal process, and this photocatalyst was successfully exploited in thiocyanation reactions at room temperature under visible light irradiation. Four classes of important heterocyclic compounds including indole, aniline, pyrrole and 2-amino thiazole derivatives via Ag/TNT treated with ammonium thiocyanate formed the corresponding thiocyano compounds in moderate to excellent yields. Plasmonic property and catalytic performance of Ag nanoparticles (which mainly deposited on the surface of TNT) in absorbing species containing sulfur atoms were key components for the reactions to proceed. This potent, simple and versatile protocol reported for the first time afforded thiocyanation reactions of aniline, pyrrole and 2-amino thiazole derivatives under visible light. The reactions proceeded through a radical pathway by applying air molecular oxygen as a low-cost and environmentally friendly terminal oxidant.
关键词： thiocyanation,photocatalyst,visible light,heterocyclic compounds,Ag/TiO2 nanotubes
更新于2025-09-04 15:30:14
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Study of silicon photomultiplier performance in external electric fields
摘要： We report on the performance of silicon photomultiplier (SiPM) light sensors operating in electric field strength up to 30 kV/cm and at a temperature of 149 K, relative to their performance in the absence of an external electric field. The SiPM devices used in this study show stable gain, photon detection efficiency, and rates of correlated pulses, when exposed to external fields, within the estimated uncertainties. No visible damage to the surface of the devices was caused by the exposure.
关键词： Cryogenic detectors,Double-beta decay detectors,Photon detectors for UV, visible and IR photons (solid-state) (PIN diodes, APDs, Si-PMTs, G-APDs, CCDs, EBCCDs, EMCCDs etc),Noble liquid detectors (scintillation, ionization, double-phase)
更新于2025-09-04 15:30:14
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Green synthesis of g-C <sub/>3</sub> N <sub/>4</sub> -Pt catalyst and application to photocatalytic hydrogen evolution from water splitting
摘要： The g-C3N4-Pt photocatalyst was successfully prepared by the combination of a biosynthesis method and sol deposition, which were used for hydrogen evolution from water splitting. The layers of g-C3N4 are thinned and the Pt nanoparticles simultaneously become tightly bound to g-C3N4 by secondary calcination in the process of synthesizing the g-C3N4-Pt photocatalyst. Analysis of the morphological structure and instrumental characterization of the optical performance revealed that the Pt nanoparticles were successfully loaded and well dispersed on the surface of g-C3N4. Furthermore, the absorption wavelength range of the g-C3N4-Pt photocatalyst in visible light was widened and the absorption increased. The activity and photostability of the g-C3N4-Pt photocatalyst for hydrogen evolution under visible light irradiation (λ≥420 nm) were excellent. The rate of H2 evolution reached 582.4 mmol h?1 g?1, and the quantum efficiency (QE) reached 2.70% at 420 nm.
关键词： green synthesis,hydrogen evolution,visible-light photocatalysis,G-C3N4-Pt photocatalyst
更新于2025-09-04 15:30:14
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Facial synthesis of a novel Ag <sub/>4</sub> V <sub/>2</sub> O <sub/>7</sub> /g‐C <sub/>3</sub> N <sub/>4</sub> heterostructure with highly efficient photoactivity
摘要： A novel Ag4V2O7/g-C3N4 heterostructure was synthesized by a facial etching method in ammonia solution using Ag2VO2PO4/g-C3N4 as a self-sacrifice precursor. With the concentration of ammonia solution increasing from 0.05 to 0.2 M, phase transformation took place, described as: Ag2VO2PO4/g-C3N4 → Ag2VO2PO4/Ag4V2O7/g-C3N4 → Ag4V2O7/g-C3N4. Compared with pristine Ag2VO2PO4/g-C3N4, the etched samples of Ag4V2O7/g-C3N4 and Ag2VO2PO4/Ag4V2O7/g-C3N4 exhibited dramatically improved activity for the degradation of methylene blue (MB), methyl orange (MO) and imidacloprid under visible light irradiation. When etched with 0.15 M ammonia solution, an Ag4V2O7/g-C3N4 heterostructure was obtained that exhibited the highest photoactivity. This photocatalyst was nearly 9.1, 3.0, and 24.3 times more efficient than pristine Ag2VO2PO4/g-C3N4 for degradation of MB, MO and imidacloprid, respectively. The excellent photocatalytic performance can be ascribed to the as-obtained well-defined Ag4V2O7/g-C3N4 heterojunction, which improves the separation and transfer efficiency and prolongs the lifetime of photoinduced charges. In addition, the stability and dominant radicals were investigated.
关键词： photocatalyst,heterostructure,Ag4V2O7/g-C3N4,visible light
更新于2025-09-04 15:30:14