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Tunable Spreading and Shrinking on Photocontrolled Liquid Substrate
摘要： Droplets of n-hexadecane were observed to shrink under ultraviolet (365 nm) and spread under blue light (475 nm) irradiation on an aqueous solution of photosensitive surfactant AzoTAB. We demonstrate that the change of wettability of n-hexadecane droplet on the solution depends on the change of oil?water interface tension. According to the addition of ethanol into the substrate, the change of relative diameter ΔD/D exceeds 20%, much larger than the system without ethanol. With light-emitting diode (LED) light as a sole power source, without any other triggers, we provide a contactless and isothermal method to realize photocontrolled alternative spreading and shrinking of a droplet on a liquid surface, which provides a basis for a chromocapillary-based optical zoom liquid lens.
关键词： photosensitive surfactant AzoTAB,oil?water interface tension,optical zoom liquid lens,n-hexadecane,UV/blue light irradiation,chromocapillary effect
更新于2025-09-12 10:27:22
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Impact of Proton and Electron Irradiation-Induced Defects on the Dark Current of GaAs Solar Cells
摘要： The same amount of non-ionizing energy is deposited in GaAs solar cells through 1 MeV proton and electron radiation at specific fluence values. The defects created are detected and characterized via temperature-dependent dark I–V analysis, and the energy levels are correlated to trap states observed via admittance spectroscopy. A remarkable difference is observed between the defect energy levels introduced in the proton and electron cases: in the former, the recombination centers lie around the mid-gap position, while in the latter they are spread over a wider energy range in the band-gap. This induces a profound difference in the degradation of the recombination current in the space-charge region. On the other hand, the degradation of the diffusion current in the neutral regions is found to be determined by the recombination velocities at the back and front hetero-interfaces of the solar cell. They depend only on the displacement damage dose and are independent of the particle type.
关键词： recombination current,semiconductor device modeling,surface recombination,Displacement damage,irradiation-induced defect,GaAs solar cell
更新于2025-09-12 10:27:22
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Generation of microcones on reaction-bonded silicon carbide by nanosecond pulsed laser irradiation
摘要： Silicon carbide (SiC) is heavily used in the industry due to its resistance to chemical wear and excellent mechanical properties such as high hardness and high stiffness. However, these properties make it difficult to produce micro and nanostructures on the surface of SiC by conventional methods. In this study, high-density microcones that protrude ~ 10 μm above the initial surface have been fabricated by nanosecond pulsed Nd:YAG laser irradiation (λ = 532 nm) on reaction-bonded SiC. Geometrically aligned cones were also fabricated by modifying the laser scanning path, and effect of different parameters such as pulse frequency, laser fluence was studied. It was observed that the surface morphology of microcones was affected by the pulse width and beam overlap. X-ray spectroscopy and Raman spectroscopy showed that the microcones were mainly composed of silicon. Formation of these cone structures made the surface highly superhydrophilic with a contact angle of ~ 0°.
关键词： Laser irradiation,Microcone,Surface texturing,Reaction-bonded silicon carbide,Superhydrophilic surface
更新于2025-09-12 10:27:22
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Diffusion of Oxygen and Nitrogen into Titanium under Laser Irradiation in Air
摘要： This paper examines the dynamic interactions between pure titanium and ambient air under transient laser processing conditions. The microstructures and composition distributions of the reaction products on and within the titanium samples are reported, which lead to the estimation of high-temperature diffusion coefficients for nitrogen and oxygen into the titanium substrate. In-situ synchrotron X-ray diffraction testing is conducted to reveal the high temperature reaction steps between titanium and air. The formation mechanisms of both titanium nitrides and titanium oxides are discussed.
关键词： titanium oxidation,titanium nitridation,synchrotron X-ray diffraction.,in-situ phase transformation,laser irradiation
更新于2025-09-12 10:27:22
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Laser Irradiation of Mung Bean ( <i>Vigna radiata</i> L.) at Two Wavelengths for Enhanced Seedling Development
摘要： Two laser sources operating at wavelengths of 632.8 nm (He-Ne) and 488 nm (Ar+) are used in examining the effects of coherent, low-power, continuous wave exposure on the development of Vigna radiata L. Presowing laser irradiation of seeds leads to an improvement of mung bean seedling characteristics, with increased values of hypocotyl length (an increase of up to 22.5%), root length (an increase of up to 28.8%), and seedling mass (a maximum increase of 29.2%). Measured parameters between seedlings from laser-irradiated seeds and from control samples are statistically different at a level of significance equal to 0.05. For both laser wavelengths, an optimal exposure time of 2 minutes is determined for enhanced growth of mung bean seedlings.
关键词： Ar+ laser,He-Ne laser,laser irradiation,mung bean,seedling development
更新于2025-09-12 10:27:22
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Performance enhancement of photovoltaic system using genetic algorithm- based maximum power point tracking
摘要： In recent years, enormous progress has been made on power generation using photovoltaic (PV) system. Solar power is one of the most promising renewable energy sources that is providing its benefit specifically in rural areas. With the increasing need for solar energy, it becomes necessary to extract maximum power from the PV array. The output power of the solar cells varies directly with the ambient temperature and Irradiation. Therefore, the challenge is to track maximum power from the PV array when environmental factors change. This paper focuses on increasing the efficiency of a PV array by incorporating artificial intelligence techniques. The genetic algorithm-based optimization technique is developed in order to track maximum power at given ambient conditions. The performance of the algorithm was tested under various environmental conditions using MATLAB/Simulink. A comparative study is done on the PV system using the conventional perturb & observe algorithm and genetic algorithm. The results show that the proposed MPPT technique is capable of tracking maximum power from the PV array with reduced oscillation and fast tracking speed.
关键词： genetic algorithm,Irradiation,optimization
更新于2025-09-12 10:27:22
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Radiation hardness of cadmium telluride solar cells in proton therapy beam mode
摘要： We evaluated the durability of cadmium telluride (CdTe) solar cells upon proton beam irradiation as well as the possibility of achieving a dosimeter usable in proton beam therapy by applying 100 MeV of pencil beam scanning (PBS) irradiation. Specifically, a 100 MeV proton PBS beam was applied at irradiation doses of 0, 1012, 1013, 1014, and 1015 cm-2. According to the results, the remaining factors (defined as the ratio of the degraded value to the initial value) of open-circuit voltage (Voc), short-circuit current (Jsc), fill-factor (FF), and efficiency (?) which are solar cell performance parameters, were approximately 89%, 44%, 69%, and 30%, respectively, compared to those of the reference cell (without irradiation) at the highest dose of 1×1015 cm-2. In particular, the conversion efficiency, which is the main factor, was approximately 70% of that of the reference cell even at a high fluence of 1×1014 cm-2. In addition, we observed the projected range of the hydrogen atoms based on the PBS beam energy using the Tool for Particle Simulation software and assessed the amount of fluence accumulated in a CdTe cell. As the energy increased, the fluence accumulated inside the cell tended to decrease owing to the characteristics of the Bragg peak of the proton. Thus, the radiation damage to the cell induced by the proton beam was reduced. The results of this study are expected to provide valuable reference information for research on dosimetry sensors composed of thin-film solar cells, serving as the basis for future application in proton beam therapy with CdTe solar cells.
关键词： radiation hardness,proton therapy,dosimetry sensors,PBS irradiation,CdTe solar cells
更新于2025-09-12 10:27:22
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Enhancement of solar cell efficiency via luminescent downshifting by an optimized coverglass
摘要： A novel approach to enhance the solar cell efficiency via employing a luminescent downshifting mechanism is presented in this work. Gold metal ions were diffused into a commercially available sodalime silicate glass using a versatile field-assisted solid-state ion diffusion technique under different experimental conditions. Some of these samples were irradiated with ns-laser to segregate the diffused ions into dimers and trimers to enhance their luminescence characteristics. The consequent structural modifications in the glass matrix were examined using Fourier transform infrared spectroscopy. Optical absorption and luminescence measurements were performed to check the presence of resonant plasmonic absorption of nanoclusters and suitability of the samples as luminescent downshifters, respectively. At UV excitation wavelengths (260 and 340 nm), the doped samples downshifted the solar spectrum compared to their undoped counterparts. Furthermore, ns-laser irradiation of the doped samples significantly enhanced the luminescence intensity in comparison to the unirradiated samples. Real-time performance of these samples was tested by measuring the output power of a Si solar cell covered with the treated coverglass when illuminated with a solar simulator. Finally, the Vicker's micro-indentation was applied to conclude that ionic diffusion increased the glass hardness as well.
关键词： Vicker's hardness,Ionic diffusion,Power conversion efficiency,Solar cell coverglass,Luminescent downshifting,Ns-laser irradiation
更新于2025-09-12 10:27:22
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Fabrication and performance of dye sensitized solar cell based on spin coated ZnS nanoparticles
摘要： ZnSx nanoparticles (NPs) with different ratios of sulfur, x = 0.5, 1 and 2, were prepared by solvothermal technique. The structural analyses, based on XRD and FTIR, show that for sulfur content x = 0.5 two phases were formed ZnS and ZnO NPs with cubic and hexagonal structure, respectively. While for sulfur content x = 1 and 2 only ZnS NPs with cubic structure was observed. The crystallites size was study before and after annealing at 500 °C. SEM images show that the prepared samples have nanocrystalline nature. Absorbance spectrum was used to calculate the optical band gap of the powder samples dispersed in potassium hydroxide solution. All samples have direct optical band gap which was inversely proportional to the sulfur content. ZnS NPs were irradiated by different doses of γ-rays and the effect on optical band gap was studied. The resulting from solvothermal preparation technique was served as precursor solution to deposit ZnSx layers onto the fluorine-doped tin oxide coated glass substrates by spinning process. The deposited ZnS NPs layers were successfully used as photoelectrode materials in dye-sensitized solar cells and the I–V characteristics were measured under illumination and in dark. An improvement in the efficiency was observed after annealing the ZnSx layers, x = 0.5 and 1, photoelectrode materials.
关键词： Dye-sensitized solar cells,Solvothermal technique,ZnS nanoparticles,γ-irradiation,Optical band gap
更新于2025-09-12 10:27:22
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Nano-sized SnO <sub/>2</sub> by a facile nanosecond laser irradiation in aqueous solution
摘要： A green and facile route was devised for the synthesis of SnO2 nanoparticles (NPs) using pulse laser irradiation of an aqueous solution of stannous chloride dihydrate and sodium hydroxide. The process employed ascorbic acid as a passivating agent, and SnO2 was obtained without any hazardous chemical reducing agent or high temperature calcination process. A nanosecond laser generating pulses with a peak wavelength of 355 nm and pulse repetition rate of 10 Hz was employed. Structural characterisations of the as-synthesized nanoparticles were carried out. The morphology of the SnO2 NPs were mostly spherical and their average crystalline sizes in the range 48.0–62.5 nm as obtained from the TEM images. The particles size showed a direct relationship with the irradiation time, and a decrease in the monodispersity was observed with increase in the time of exposure to the laser beam. The photocatalytic activity of the NPs, obtained with the least time of exposure to the laser beam, was evaluated for the photodegradation of methylene blue under visible light. The nanoparticles achieved about 84% efficiency towards the degradation of the dye within 180 min.
关键词： methylene blue,SnO2,laser irradiation,photocatalysis,nanoparticles
更新于2025-09-12 10:27:22