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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
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- University of Huddersfield
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Fabrication of high efficiency visible light Z-scheme heterostructure photocatalyst g-C3N4/Fe0(1%)/TiO2 and degradation of rhodamine B and antibiotics
摘要： We have prepared and studied a novel low cost catalyst of g-C3N4/Fe0(1%)/TiO2, using a simple process involving the formation of zero valence iron by chemical reduction. This ternary catalyst g-C3N4/Fe0(1%)/TiO2 was characterized using XRD (X-Ray diffraction), UV–vis spectrum, EDS (Energy Dispersive spectrum) and TEM (transmission electron microscopy), it demonstrated high-visible-light activity in a wide range of pH condition, it can photo-catalytically degraded Rhodamine B (RhB), Tetracycline (TC), and Berberine hydrogen chloride (BH) (～98% in 90 min) under visible light. The high activity arises from the increased harvest of more visible light and the improved separation of photo-excited electrons and holes via Z-scheme and heterojunctions mechanism. Also, the time required to remove 100% RhB, TC, and 96% BH can be shortened from 90 min to 60 min by introducing 3.18 mM Na2SO3 to this photocatalysis system that assisted the generation of reactive oxidizing species and pollutant degradation. The results showed promising application prospect for this developed catalyst and the tested photocatalysis pollutant degradation system.
关键词： Antibiotics,z-scheme heterostructure,Rhodamine B,g-C3N4/Fe0(1%)/TiO2 photocatalyst,Visible-light
更新于2025-09-23 15:23:52
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TiO2/MoS2 heterojunctions-decorated carbon fibers with broad-spectrum response as weaveable photocatalyst/photoelectrode
摘要： The development of efficient and recyclable photocatalysts with wide spectrum response has drawn much attention. Herein, we prepared TiO2/MoS2 heterostructures on carbon fibers (CFs) by a two-step hydrothermal method. CFs/TiO2/MoS2 exhibits a strong and wide absorption spectrum from ultraviolet to near-infrared region (> 1200 nm). Under the irradiation of visible-light, CFs/TiO2/MoS2 could degrade 97.6% Rhodamine B (RhB) after 100 min, 94.2% Acid Orange 7 (AO7) or 93.4% tetracycline hydrochloride (TC) after 60 min, and 88.7% 4-chlorophenol (4-CP) after 180 min. Moreover, CFs/TiO2/MoS2 bundles can be further weaved into a cloth (area: 4 × 4 cm2). CFs/TiO2/MoS2 cloth as a working electrode exhibits significant photocurrent (7.53 × 10?6 A/cm2) and enhanced photoelectrocatalytic efficiency (100% TC) comparing with only photocatalysis (90.7% TC) or electrocatalysis (47% TC). In particular, CFs/TiO2/MoS2 cloth shows excellent stability. Therefore, CFs/TiO2/MoS2 cloth has great potential to be used as flexible and weaveable photocatalyst/photoelectrode for degrading various pollutants.
关键词： Photoelectrocatalysis,Photocatalyst,Carbon fibers,Visible-light,TiO2/MoS2
更新于2025-09-23 15:23:52
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One-pot synthesis of visible-light-driven photocatalyst for degradation of Rhodamine B: graphene based bismuth/bismuth(III) oxybromide
摘要： A ternary photocatalyst, graphene based bismuth modified bismuth(III) oxybromide (Bi/BiOBr/G), was synthesized via a facile one-step solvothermal method using only ethylene glycol as both solvent and reducing reagent. Bi/BiOBr/G exhibits higher photocatalytic activity than bismuth(III) oxybromide (BiOBr) on degradation of Rhodamine B under visible-light illumination, and the photodegradation rate is 4.9 times that of BiOBr. The enhanced photocatalytic activity is attributed to the synergistic effect among Bismuth, graphene and BiOBr, which can effectively promote the visible-light absorption of Bi/BiOBr/G and the separation of photogenerated charge carriers. The conditions influencing the photocatalytic performance of Bi/BiOBr/G were also investigated in detail, as well as the photocatalytic mechanism of the degradation.
关键词： Nanocomposites,Semiconductors,Carbon materials,Photocatalytic activity,Visible light
更新于2025-09-23 15:23:52
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Numerical study of a wide-angle and polarization-insensitive ultrabroadband metamaterial absorber in visible and near-infrared region
摘要： An ultrabroadband metamaterial absorber structure based on a periodic array of metallic-dielectric multilayered conical frustums is numerically investigated and proposed. The metamaterial absorber indicated an absorptivity of higher than 90%, which covered the visible and near-infrared region at 480-1480 nm, and a relative absorption bandwidth of 102%. The high absorptivity can be maintained with large incident angles up to 60° under both transverse electric and transverse magnetic polarizations. Furthermore, the proposed absorber exhibits polarization insensitivity owing to its rotational symmetry structure. Compared with the previously reported ultrabroadband metamaterial absorbers, the design in this work indicates high practical feasibility in terms of compact structure for large bandwidth, wide incident angle and polarization insensitivity, thereby suggesting its promising application, for example, in solar cells and thermal emitters.
关键词： Metamaterial,Absorber,Visible,Ultrabroadband,Near-Infrared
更新于2025-09-23 15:23:52
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Optimization of Non-Orthogonal Multiple Access based Visible Light Communication Systems
摘要： In Visible Light Communication (VLC), the data is transmitted by modulating the Light Emitting Diode (LED). The data-rate is throttled by the narrow modulation bandwidth of LEDs which results as a barrier in attaining high transmission rates. Non-Orthogonal Multiple Access (NOMA) is a new Multiple Access (MA) scheme envisioned to improve the system capacity. In addition to MA schemes, optimization techniques are applied to further improve the data-rate. In this letter, convex optimization is applied on NOMA-based VLC system for downlinks. The proposed optimization system is analyzed in terms of the Bit Error Rate (BER) and the sum-rate.
关键词： Sum-rate maximization,Visible Light Communication,Non-Orthogonal Multiple Access (NOMA),Convex Optimization,5G
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - High Speed Novel Hybrid Modulation Technique of Visible Light Communication Based on Artificial Neural Network Equalizer
摘要： Visible light communication (VLC) which realizes data transmission and universal illumination simultaneously has attracted much attention recently. However, the transmission rate of the VLC remains low due to the low bandwidth performance and inter-symbol interference (ISI). Therefore, a hybrid approach using pulse amplitude modulation and pulse width modulation in conjunction with an artificial neural network (ANN) equalizer is proposed, which can theoretically increase the transmission rate by 4 times compared with the traditional way, and provide variable brightness to realize the integration of data transmission and illumination control. In addition, an artificial neural network equalizer is proposed to undo the effects of ISI, considering that the bandwidth of the LED is only 3MHz. Without the ANN equalizer, the maximum transmission rate of the proposed hybrid modulation link only reaches 36 Mbps under the condition of no signal processing; however, with the ANN equalizer, the transmission speed can up to 2.6 Gbps. The proposed system not only achieves a genuine combination of data transmission and control illumination levels, but also realizes a high data rate with less complexity.
关键词： code division multiple access,pulse amplitude modulation,visible light communication,artificial neural network equalizer
更新于2025-09-23 15:23:52
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Facile fabrication of phosphorus-doped g-C3N4 exhibiting enhanced visible light photocatalytic degradation performance toward textile dye
摘要： Phosphorus-doped graphitic carbon nitride (P-g-C3N4) was facilely fabricated by in situ thermal copolymerization of urea and triphenylphosphine source materials. The P-g-C3N4 exhibited an enhanced photocatalytic performance than pristine g-C3N4 counterpart for the degradation of rhodamine B and acid blue D-2BR textile dye under visible light irradiation. X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption isotherms, X-ray photoelectron spectra (XPS), and diffuse reflection spectroscopy (DRS) techniques were used to characterized the structure and property of P-g-C3N4 photocatalyst. The phosphorus doping enhanced visible light harvesting and surface area, but also substantially changed the electronic property of g-C3N4 material that could suppress the recombination of photogenerated charge carriers, and thus improved photocatalytic performance.
关键词： Textile dye,Porous photocatalyst,Visible light,Degradation,Phosphorus-doped g-C3N4
更新于2025-09-23 15:23:52
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Effect of Co component in Co-Ag granular thin films on visible-light reflection applied by magnetic field
摘要： The reflection of visible light (wavelength from 350 to 800 nm) on magnetic granular thin films Cox-Ag1-x with x from 0 to 35 at % was studied. Dependence of reflection (R) is strong on magnetic and percentage of Co in the thin films, R strongly increase in wavelengths 560 and 660 nm. In this paper, some arguments relating to the spin-plasmon phenomenon were used to explain the results.
关键词： spin-plasmon,Granular magnetic thin films,visible light,reflection
更新于2025-09-23 15:23:52
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Nanocrystal-engineered thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of organic pollutant in aqueous solution
摘要： We design a thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of methylene blue (MB). Nanocrystal engineering of the photocatalyst is performed by sputtering with concurrent in-situ thermal treatment. The impacts of the in-situ thermal treatment temperature and sputtering conditions on the material properties of the thin CuO film photocatalyst are investigated in detail. Systematic characterization using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) indicates that deposition at elevated temperature and higher sputtering power significantly improves the surface structure and crystallinity of thin CuO film, which promotes charge transfer and ultimately results in better performance for MB photocatalytic degradation. The best-performing sample is the one sputtered at an elevated temperature of 300 °C and a sputtering power of 300 W. The photodegradation efficiency and physical durability of the samples were also analyzed after using for 5 cycles. The results indicate that in-situ thermal treatment and nanocrystal engineering of the thin CuO film significantly improve the physical durability.
关键词： Thin CuO film photocatalyst,Visible-light-driven photocatalytic degradation,Nanocrystal engineering
更新于2025-09-23 15:23:52
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Visible Light Driven Hydrogen Evolution by Molecular Nickel Catalysts with Time-Resolved Spectroscopic and DFT Insights
摘要： Hydrogen (H2) is a clean fuel that can potentially be a future solution for the storage of intermittent renewable energy. However, current H2 production is mainly dominated by the energy intensive steam reforming reaction, which consumes a fossil fuel, methane, and emits copious amounts of carbon dioxide as one of the byproducts. To address this challenge, we report a molecular catalyst that produces H2 from aqueous solutions, is composed of affordable, earth-abundant elements such as nickel, and has been incorporated into a system driven by visible light. Under optimized conditions, we observe a turnover number of 3880, among the best for photocatalytic H2 evolution with nickel complexes from water?methanol solutions. Through nanosecond transient absorption, electron paramagnetic resonance, and UV?vis spectroscopic measurements, and supported by density functional theory calculations, we report a detailed study of this photocatalytic H2 evolution cycle. We demonstrate that a one-electron reduced, predominantly ligand-centered, reactive Ni intermediate can be accessed under visible light irradiation using triethylamine as the sacrificial electron donor and reductive quencher of the initial photosensitizer excited state. In addition, the computational calculations suggest that the second coordination sphere ether arms can enhance the catalytic activity by promoting proton relay, similar to the mechanism among [FeFe] hydrogenases in nature. Our study can form the basis for future development of H2 evolution molecular catalysts that incorporate both ligand redox noninnocence and alternative second coordination sphere effects in artificial photosynthetic systems driven by visible light.
关键词： Proton relay,Second coordination sphere,DFT calculations,Time-resolved spectroscopy,Visible light photocatalysis,Hydrogen evolution,Molecular nickel catalysts
更新于2025-09-23 15:23:52