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Preparation and characterization of bismuth oxychloride/reduced graphene oxide for photocatalytic degradation of rhodamine B under white-light light-emitting-diode and sunlight irradiation
摘要： Facile and template-free two-step synthesis of bismuth oxychloride/graphene oxide (BiOCl/GO) and bismuth oxychloride/reduced graphene oxide (BiOCl/rGO) photocatalysts for degradation of rhodamine B (RhB) under low-power white light–emitting diode (wLED) irradiation (1.6 W/cm2) and sunlight is demonstrated. These photocatalysts were characterized by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray di?raction, and micro-Raman, Fourier-transform infrared, X-ray photoelectron, and UV–Vis di?use re?ectance spectroscopy. Under wLED irradiation, the prepared BiOCl/rGO photocatalysts exhibited excellent photodegradation activity toward RhB through chromophore cleavage mechanism and toward phenol in the presence of RhB with notable dye-sensitized e?ect. Through scavenging experiments, superoxide radicals were notably involved in RhB degradation. With the highest charge separation e?ciency and lowest recombination rate, the photocatalytic activity of BiOCl/rGO reached a maximum rate constant of 0.1899 min?1, 2.0 and 3.0 times higher than those of BiOCl/GO and BiOCl, respectively. In the stability study, only a slight loss (4.5%) in photodegradation was observed after BiOCl/rGO was used in ?ve cycles of photodegradation runs. Compared with commonly used photocatalyst such as TiO2 (P25), BiOCl/rGO demonstrated superior photocatalytic activity and stability under wLED irradiation for various dyestu?s (rhodamine 6 G, methylene blue, and fast green FCF) in di?erent environmental water samples (lake, pond, and sea water).
关键词： wLED-induced photodegradation,Rhodamine B,Reduced graphene oxide,Phenol,Sunlight irradiation,Bismuth oxychloride
更新于2025-09-19 17:15:36
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Reduction of electrical power loss in a photovoltaic chain in conditions of partial shading
摘要： The paper presents the problem of losses of electrical power in photovoltaic chains during partial shading. Photovoltaic modules work best when the illumination is uniform over the entire light-sensitive surface. If a part of this surface is illuminated to a lesser extent, it often ceases to be a part of the electricity generator, but constitutes a resistance. To minimize this phenomenon, PV modules use bypass diodes, e.g. covering several dozen cells in a photovoltaic chain. In addition, parts of the photovoltaic module surface with lower exposure to sunlight may be additionally illuminated with a mirror positioned to reflect light. The analysis uses a photovoltaic chain model implemented in MATLAB/Simulink. The model describes the processes of electrical power generation in photovoltaic modules. The model corresponds to a laboratory photovoltaic system located in AGH in Cracow. In the presented model, each individual part may be illuminated with different light intensity. The light incident on the cells is a direct sunlight or light reflected from the mirror. The model allows for the analysis of the electrical power generated depending on the light profile of the photovoltaic system. The results of the model analysis may be applied in optimization of the PV modules’ configuration.
关键词： Partial shading,Modelling,Photovoltaic system,Sunlight reflection,Maximum power point tracking (MPPT)
更新于2025-09-19 17:13:59
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SILICA a?? CARBON QUANTUM DOTS DECORATED TITANIUM DIOXIDE AS SUNLIGHT-DRIVEN PHOTOCATALYST TO DIMINISH ACETAMINOPHEN FROM AQUATIC ENVIRONMENT
摘要： The presence of pharmaceutical compound (i.e., acetaminophen) in aquatic environment has been declared as environmental issue since researchers found that it has potential risk to human health. Photocatalytic process as a promising method for waste degradation commonly employs titanium dioxide, TiO2. However, TiO2 has narrow light absorption and rapid charge recombination resulting in ineffective photocatalytic activity. In this study, silica – carbon quantum dots (Si-CQDs) from rice husk are decorated into TiO2 matrix through facile mixing approach to minimize the limitations of TiO2. Preliminary studies regarding TiO2 transformation and Si-CQDs incorporation in various amount were systematically investigated. It is observed that 1 wt% is the optimum amount of Si-CQDs in composite in order to maximize the photocatalytic ability of TiO2. Under sunlight irradiation, 1 wt% Si-CQDs/TiO2 composite is able to completely degrade 5 mg/L of acetaminophen within 240 min (33.3% faster than pure TiO2). The excellent performance of the composite is attributed to synergistic effect of Si-CQDs addition on TiO2 surface, which acted as photo sensitizer and electron trapper. Si-CQDs extend light absorption of TiO2 by reducing band gap energy from 3.20 to 3.12 eV, as confirmed by UV-Vis Diffuse Reflectance Spectroscopy (DRS) spectra. Photoluminescence (PL) spectra and N2 sorption isotherm reveal that Si-CQDs addition prolongs the lifetime of charge separation and improves surface area (17% larger than TiO2), respectively. The composite of Si-CQDs/TiO2 also demonstrates good stability which is beneficial for pharmaceutical waste removal in the future.
关键词： sunlight,photocatalyst,Titanium dioxide,acetaminophen,carbon quantum dots,pharmaceutical
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Up-Conversion Threshold under Concentrated Sunlight
摘要： We investigate the two-photon threshold of rare-earth up-conversion under concentrated sunlight, in a solar furnace that generates an irradiance of up to 2606 suns on the samples. One of the most efficient up-converters currently available, NaYF4: Er3+ was used. We established a threshold by experimentally observing the transition for up-conversion photoluminescence from a quadratic relation to linear relation as solar concentration was increased. We further investigated the role of energy transfer on the threshold, observing the same threshold for a higher Er3+ content of 50%, but a threshold that exceeds 2300 suns at 15% Er3+. In this way, a tangible limit for the benefit and effect of solar concentration on up-conversion can be obtained for photovoltaic and solar thermal applications.
关键词： photovoltaic,concentrated sunlight,up-conversion,photoluminescence,solar concentration,solar thermal applications
更新于2025-09-16 10:30:52
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Development of Sunlight LED Bollard Based on C/GFRP Floodlight Composite
摘要： It is safe and light because it uses carbon/glass fiber reinforced plastics (hereinafter referred to as C/GFRP) through this technological development. Moreover, sunlight LED luminous bollard, which was harmonized with the surrounding environment with diverse colors, was developed. Luminous bollard can reduce its weight and also increase its strength by adjusting the intensity and thickness of a product customized for each usage on the basis of the characteristics of C/GFRP composite. In addition, C/GFRP and steel pipe were compared for the compression test in order to compare the objective rigidity. As a result, this study could obtain a positive result graph of luminous bollard. To develop luminous bollard, the composite development process was configured through a fixture of pullout and filament winding. Diverse colors can be applied to luminous bollard. Hence, it is possible to select a color customized for each region. It is also possible to create an aesthetic harmony with a surrounding environment through LED lamps at night. The pipe, which was 50 percent lighter than stainless and also which had excellent tensile strength, was designed to develop the bollard that has superior convenience in terms of construction, maintenance and repair.
关键词： Sunlight,Elastic force,Bollard,C/GFRP (Carbon/Glass Fiber Reinforced Plastics)
更新于2025-09-16 10:30:52
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Enhanced photocatalytic degradation of antibiotics in water over functionalized N,S-doped carbon quantum dots embedded ZnO nanoflowers under sunlight irradiation
摘要： ZnO is widely used as a photocatalyst in industry, however, it is still a challenge to degrade refractory antibiotics in water. In this study, a novel surface-functionalized N,S-doped carbon quantum dot (N,S-CQD) was synthesized and embedded into ZnO for the formation of a new ZnO/N,S-CQDs hybrid nanoflower via one-pot hydrothermal process. The as-prepared ZnO/N,S-CQDs showed significantly enhanced photocatalytic activity under visible and near-infrared (NIR) light irradiation, in which 72.8% of MG was decomposed after 180 min under NIR light. In addition, approximately 92.9% and 85.8% of ciprofloxacin (CIP) were degraded by ZnO/N,S-CQDs under simulated sunlight for 20 min and natural sunlight for 50 min, respectively. Furthermore, the mechanism was investigated and the results show that the surface functionalization, electron transfer, up-converted luminescence properties of N,S-CQDs, together with the highly reactive facets of ZnO nanoflowers, made great contributions to the enhanced photocatalytic activity of ZnO/N,S-CQDs. Additionally, the results of active species trapping experiments indicated that the hydroxide free radicals, holes and superoxide radical anions all played certain roles in the photocatalytic reaction. Finally, ZnO/N,S-CQDs was employed for photodegradation of antibiotics in actual water, the degradation efficiency of antibiotics still remained above 60% after 120 min. We believe that the ZnO/N,S-CQDs nanoflower is a promising photocatalyst for the degradation of refractory antibiotics under sunlight irradiation. The relatively low cost and excellent photocatalytic performance of ZnO/N,S-CQDs is beneficial for industrial applications.
关键词： antibiotics,carbon quantum dots,ZnO nanoflowers,photocatalysis,sunlight irradiation
更新于2025-09-16 10:30:52
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Performance enhancement of bulk heterojunction organic solar cells using photon upconverter
摘要： In this article, we show that significant performance enhancement can be obtained by incorporating a photo upconverter layer in bulk heterojunction organic solar cells (BHJ OSCs). We systematically optimize the photon upconversion process for P3HT:PCBM, PSBTBT:PCBM, PBDTTT-C:PCBM and PTB7-Th:PCBM based BHJ OSCs using a simple numerical model followed by optoelectronic simulations. After verifying the integrated model of upconversion with experimental reports, we analyze each type of BHJ OSC incorporating photon upconversion layer having optimized spectral characteristics and estimate efficiency enhancement of ~30.8% (4.55% → 5.95%), ~24.3% (5.02% → 6.24%), ~28.9% (6.35% → 8.19%) and ~16.9% (10.55% → 12.34%) for P3HT:PCBM, PSBTBT:PCBM, PBDTTT-C:PCBM and PTB7-Th:PCBM based OSCs, respectively. We then show that effect of photon upconversion and localized surface plasmon resonance on the best performing OSC material considered in this work i.e. PTB7-Th:PCBM, is non-linear and predict a performance boost of mere ~2.3% (12.32% → 12.62%) from additional effort (due to plasmon resonance). Finally, we discuss possibility of extending the efficiency of PTB7-Th:PCBM based BHJ OSC beyond 16% using concentrated sunlight and a practically realizable upconverter layer.
关键词： Organic solar cell,Photon upconversion,Bulk heterojunction,Concentrated sunlight
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Compromise solutions for design and technology of Fresnel lenses as sunlight concentrators
摘要： In the paper, the approaches to the Fresnel lens design in a rectilinear (“classical”) and a curvilinear (“aspherical”) refracting profile versions are discussed regarding silicone-on-glass and 3D printing technology. The advantages of short-focus lenses with an increased Fresnel profile pitch are shown. The mathematical model used for concentrating solar radiation based on direct tracking of rays has made it possible to solve the problems of designing the concentrators and comparing their characteristics with due account for limitations of the manufacturing methods used and the Fresnel lens shape errors arising from manufacturing. Optimized design parameters of Fresnel lenses based on silicone (Wacker 604) and thermoplastic (Luxexcel Opticlear) materials are presented.
关键词： optical efficiency,silicone-on-glass,chromatic aberration,Fresnel lenses,sunlight concentrators,3D printing
更新于2025-09-11 14:15:04
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Amalgamation of N-graphene quantum dots with nanocubic like TiO2: an insight study of sunlight sensitive photocatalysis
摘要： In this work, a sunlight-sensitive photocatalyst of nanocubic-like titanium dioxide (TiO2) and N-doped graphene quantum dots (N-GQDs) is developed through a simple hydrothermal and physical mixing method. The successful amalgamation composite photocatalyst characteristics were comprehensively scrutinized through various physical and chemical analyses. A complete removal of bisphenol A (BPA) is attained by a synthesized composite after 30 min of sunlight irradiation as compared to pure TiO2. This clearly proved the unique contribution of N-GQDs that enhanced the ability of light harvesting especially under visible light and near-infrared region. This superior characteristic enables it to maximize the absorbance in the entire solar spectrum. However, the increase of N-GQDs weight percentage has created massive oxygen vacancies that suppress the generation of active radicals. This resulted in a longer duration for a complete removal of BPA as compared to lower weight percentage of N-GQDs. Hence, this finding can offer a new insight in developing effective sunlight-sensitive photocatalysts for various complex organic pollutants degradation.
关键词： Visible light,Near Infrared,Nanocubic-like TiO2,Bisphenol A,N-Graphene quantum dots,Sunlight
更新于2025-09-10 09:29:36
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MEDIUM SIZE DUAL-AXIS SOLAR TRACKING SYSTEM WITH SUNLIGHT INTENSITY COMPARISON METHOD AND FUZZY LOGIC IMPLEMENTATION
摘要： Nowadays, renewable energy such as solar power has become important for electricity generation, and solar power systems have been installed in homes. Furthermore, solar tracking systems are being continuously improved by researchers around the world, who focus on achieving the best design and thus maximizing the efficiency of the solar power system. In this project, a fuzzy logic controller has been integrated and implemented in a medium-scale solar tracking system to achieve the best real-time orientation of a solar PV panel toward the sun. This project utilized dual-axis solar tracking with a fuzzy logic intelligent method. The hardware system consists of an Arduino UNO microcontroller as the main controller and Light Dependent Resistor (LDR) sensors for sensing the maximum incident intensity of solar irradiance. Initially, two power window motors (one for the horizontal axis and the other for the vertical axis) coordinate and alternately rotate to scan the position of the sun. Since the sun changes its position all the time, the LDR sensors detect its position at five-minute intervals through the level of incident solar irradiance intensity measured by them. The fuzzy logic controller helps the microcontroller to give the best inference concerning the direction to which the solar PV panel should rotate and the position in which it should stay. In conclusion, the solar tracking system delivers high efficiency of output power with a low power intake while it operates.
关键词： Dual-axis tracker,sunlight intensity comparison method,solar renewable energy,fuzzy logic
更新于2025-09-10 09:29:36