- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
aSi:H/i-aSi:H/p+aSiGe:H Graded Band Gap Single Junction Solar Cell
摘要： In this paper, we present a single junction graded band gap thin film solar cell using heavily phosphorous doped amorphous silicon, intrinsic amorphous silicon and heavily boron doped amorphous silicon germanium. The first part of the work presents a rigorous analysis of J-V characteristics of recommended photovoltaic structure under short circuit (SC), open circuit (OC), dark and AM 1.5G illumination standard. Further, optimisation of thickness of active layers of the suggested n+aSi:H/i aSi:H/p+aSiGe:H solar cell structure is done using SCAPS1D solar simulator. The active layer thickness of the proposed solar cell is 430 nm only. Low active layer thickness and absence of multiple junctions reduces the material requirement, complexity and cost of the proposed solar cell. Furthermore, fabrication of individual layers and overall summary of their characterisation have been done. Finally, the proposed structure has been fabricated and validated its J-V characteristics. The fabricated solar cell has short circuit current density (Jsc) of 11.67 mA/cm2, open circuit voltage (Voc) of 1.18 V, fill factor (FF) of 0.857 and conversion efficiency (η) of 11.80 % which is on par with other announced single junction amorphous silicon solar cells. Here, we are reporting a single junction graded band gap solar cell using combination of aSi:H and aSiGe:H alloys with varying doping levels for the first time, which is better in conversion efficiency while compact and light.
关键词： SCAPS1D,graded bandgap,amorphous silicon germanium,J-V characteristics,PECVD,Amorphous Silicon Alloys
更新于2025-09-19 17:13:59
-
Quantitative remote and on-site Hg2+ detection using the handheld smartphone based optical fiber fluorescence sensor (SOFFS)
摘要： Di-n-butyl ether (DBE) is one of the most promising alternative biofuels for vehicles due to its superior physicochemical properties and because it is a renewable resource. This study investigated the effects of DBE addition on the spray macroscopic characteristics of diesel-biodiesel blends under various injection and ambient conditions. Three kinds of ternary blended fuels were prepared—(1) 72% diesel, 18% biodiesel, 10% DBE by volume (D72B18DBE10); (2) 64% diesel, 16% biodiesel, 20% DBE by volume (D64B16DBE20); and (3) 56% diesel, 14% biodiesel, and 30% DBE by volume (D56B14DBE30)—in order to compare their spray characteristics with those of an 80% diesel–20% biodiesel mix (D80B20) and conventional diesel (D100). The experiments were conducted in a constant volume chamber with a high-pressure common rail injection system using a high-speed photography method. The results show that D80B20 gives the longest spray tip penetration and the smallest cone angle and projected area among the five test fuels. With increased DBE blending ratio, the spray penetration length decreases slightly, and spray cone angle and projected area increase. When the DBE volume fraction in the ternary blend is 20%, the spray tip penetration, cone angle, and projected area are comparable to those of diesel. In addition, air entrainment characteristics were analyzed with the quasi-steady jet theory. It was found that the addition of DBE can improve the air entrainment characteristics of diesel-biodiesel blends, and D64B16DBE20 results in fuel-air mixing similar to that of D100.
关键词： Biodiesel,Diesel,Di-n-butyl ether,Spray characteristics
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 7th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Liepaja, Latvia (2019.11.15-2019.11.16)] 2019 IEEE 7th IEEE Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Phase and Attenuation Characteristics of Models of GaAs Semiconductor Waveguides in Case of Two Layers
摘要： Models of cylindrical multilayer semiconductor-anisotropic-semiconductor dielectric-anisotropic-semiconductor waveguides are presented in this paper. We have selected n-GaAs semiconductor and TM-15 dielectric as a core of the presented waveguides. Anisotropic TM-15 and Rb1?x(ND4)D2PO4 dielectrics and n-InAs1-xSbx semiconductor we used for the external layers of waveguides. The influence of different core materials and temperature to the waves phase characteristics and attenuation was evaluated. Differential Maxwell’s equations, coupled mode, and boundary condition methods were used during the investigation. The density of electrons was constant and equal to N = 5·1019 m–3 during all investigations. The temperature has varied in the range of 125–200 K. Results have showed that material of the core, external layers and temperature has a big impact on the phase and attenuation characteristics of the waveguide and these types of waveguides could be used in the manufacture of phase shifters and attenuators.
关键词： phase characteristics,microwave devices,attenuation,semiconductor waveguides
更新于2025-09-19 17:13:59
-
CaOH Molecular Emissions in Underwater Laser-Induced Breakdown Spectroscopy: Spatial–Temporal Characteristics and Analytical Performances
摘要： Recently, molecular emissions from the laser-induced plasma in ambient gas have gained increasing interest; however, very little is known about the case in water solutions. In this work, we investigated the spatiotemporal characteristics of molecular emissions, CaOH for instance, in underwater laser-induced breakdown spectroscopy (LIBS) by using time-resolved spectroscopy, spectral-resolved imaging, and shadowgraph techniques. It was shown that clear CaOH molecular bands can be observed in the spectrum at very early times after the laser pulse and presented a much longer lifetime and more homogeneous emission distribution compared with the Ca I and Ca II lines. Such unique characteristics of CaOH molecular emission inspired us to improve the performances of underwater LIBS by using the CaOH molecular bands instead of Ca I and Ca II lines. We demonstrated the excellent quanti?cation results of CaOH with higher stability, less self-absorption, and reduced matrix e?ect. Meanwhile, the limit of detection (LOD) of Ca with the CaOH molecular band (2.46 ppm) is comparable to that with the atomic line of Ca I (2.07 ppm), and much lower than that with the ionic line of Ca II (13.81 ppm), indicating a good sensitivity of CaOH. This work gives not only some insights into the molecule formation mechanisms in underwater plasmas, but also provides new ideas to improve the analytical performances of underwater LIBS.
关键词： analytical performances,CaOH molecular emissions,underwater laser-induced breakdown spectroscopy,spatiotemporal characteristics
更新于2025-09-19 17:13:59
-
Occurrence frequencies and regional variations in Visible Infrared Imaging Radiometer Suite (VIIRS) global active fires
摘要： Active fires are considered to be the key contributor to, and critical consequence of, climate change. Quantifying the occurrence frequency and regional variations in global active fires is significant for assessing carbon cycling, atmospheric chemistry, and post-fire ecological effects. Multi-scale variations in fire occurrence frequencies have still never been fully investigated despite free access to global active fire products. We analyzed the occurrence frequencies of Visible Infrared Imaging Radiometer Suite (VIIRS) active fires at national, pan-regional (tropics and extra-tropics) to global scales and at hourly, monthly, and annual scales during 2012-2017. The results revealed that the accumulated occurrence frequencies of VIIRS global active fires were up to 12,193×104, yet exhibiting slightly fluctuations annually and with respect to the 2014-2016 El Ni?o event, especially in 2015. 35.52% of VIIRS active fires occurred from July to September, particularly in August (13.06%), and typically between 10:00 Greenwich Mean Time (GMT) and 13:00 GMT (42.96%) and especially at 11:00 GMT (17.65%). The total counts conform to a bimodal pattern with peaks in 5°-11°N (18.01%) and 5°-18°S (32.46%), respectively, alongside a unimodal distribution in terms of longitudes between 15°E and 30°E (32.34%). Tropical annual average of active fire (1,496.81×104) accounted for 75.83%. Nearly 30% were counted in Brazil, the Democratic Republic of the Congo (DRC), Indonesia and Mainland Southeast Asia (MSEA). Fires typically occurred between June (or August) and October (or November) with far below-average rainfall in these countries, while those in MSEA primarily occurred between February and April during the dry season. They were primarily observed between 00:00 GMT and 02:00 GMT, between 12:00 and 14:00 within each Zone Time. We believed that VIIRS global active fires products are useful for developing fire detection algorithms, discriminating occurrence types and ignition causes via correlation analyses with physical geographic elements, and assessment their potential impacts.
关键词： Active fires,Tropical region,Occurrence frequency,Spatio-temporal characteristics,Visible Infrared Imaging Radiometer (VIIRS)
更新于2025-09-19 17:13:59
-
Series DC Arc Simulation of Photovoltaic System Based on Habedank Model
摘要： Despite the rapid development of photovoltaic (PV) industry, direct current (DC) fault arc remains a major threat to the safety of PV system and personnel. While extensive research on DC fault arc has been conducted, little attention has been paid to the long-time interactions between the PV system and DC arc. In this paper, a simulation system with an arc model and PV system model is built to overcome the inconvenience of the fault-arc experiments and understand the mechanism of these interactions. For this purpose, the characteristics of the series DC arc in a small grid-connected PV system are ?rst investigated under uniform irradiance. Then, by comparing with di?erent arc models, the Habedank model is selected to simulate the fault arc and a method to determine its parameters under DC arc condition is proposed. The trends of simulated arc waveforms are consistent with the measured data, whose ?tting degree in adjusted R-squared is between 0.946 and 0.956. Finally, a phenomenon observed during the experiment, that the negative perturbation of the maximum power point tracking (MPPT) algorithm can reduce the arc current, is explained by the proposed model.
关键词： PV arc fault,fault arc simulation,renewable energy,DC arc model,arc characteristics
更新于2025-09-19 17:13:59
-
Modelling solar cellsa?? S-shaped I-V characteristics with an analytical solution to lumped-parameter equivalent circuit model
摘要： In this paper, an analytical solution to three-diode lumped-parameter equivalent circuit model is proposed to simulate and present S-shaped I-V characteristics of next generation solar cells, which are observed frequently in perovskite and organic solar cells, and occasionally in other kinds of solar cells. In general, because complicated transcendental equation includes three exponent items resulting from three diodes, the absence of an analytical solution has become a bottleneck that limits the adoptions of solar cells’ three-diode lumped-parameter model into practical applications and device simulations. To break through the above bottleneck, the analytical solution is derived in the regional approach, completed in Matlab platform, and verified by reconstructed experimental data measured from real solar cells. Such an analytical solution processes the key feature with high precise and efficiency. High precise results from the mathematical operations of the analytical solution to lumped-parameter model and high efficiency results from the avoidance of numerical iteration methods. In addition, this analytical solution facilitates researchers to accurately determine short circuit current and open circuit voltage, quickly extract model parameters in lumped-parameter circuit, and in detail assess effects from model parameters on DC characteristics of solar cells. Finally, the proposed analytical solution is able to be used to reproduce S-shaped I-V characteristics of solar cells, assist in extracting fitting parameters in three-diode lumped-parameter equivalent circuit model, and complete implementation of model into semiconductor device and circuit simulators.
关键词： Lumped-parameter equivalent circuit model,S-shaped I-V characteristics,Solar cells,Analytical solution
更新于2025-09-19 17:13:59
-
Low-Power, Multimodal Laser Micromachining of Materials for Applications in sub-5 ?μm Shadow Masks and sub-10 ?μm Interdigitated Electrodes (IDEs) Fabrication
摘要： Laser micromachining is a direct write microfabrication technology that has several advantages over traditional micro/nanofabrication techniques. In this paper, we present a comprehensive characterization of a QuikLaze 50ST2 multimodal laser micromachining tool by determining the ablation characteristics of six (6) different materials and demonstrating two applications. Both the thermodynamic theoretical and experimental ablation characteristics of stainless steel (SS) and aluminum are examined at 1064 nm, silicon and polydimethylsiloxane (PDMS) at 532 nm, and Kapton? and polyethylene terephthalate at 355 nm. We found that the experimental data aligned well with the theoretical analysis. Additionally, two applications of this multimodal laser micromachining technology are demonstrated: shadow masking down to approximately 1.5 μm feature sizes and interdigitated electrode (IDE) fabrication down to 7 μm electrode gap width.
关键词： interdigitated electrodes,ablation characteristics,multimodal laser micromachining,shadow mask
更新于2025-09-19 17:13:59
-
Underwater wire-feed laser deposition of the Ti–6Al–4V titanium alloy
摘要： Underwater wire-feed laser deposition (UWLD) of the Ti-6Al-4V alloy was firstly carried out utilizing a laser deposition nozzle, and the deposition appearance, geometry characteristics, microstructure and microhardness of deposited tracks were studied. At a lower gas flow rate, the absorption of residual water and scattering of aerosol particles on laser beam caused UWLD instability and decreased molten metal wettability. Upon increasing the gas flow rate, the aerosol particle density decreased, increasing the laser density and decreasing the cooling rate of molten metal; thus, the height and deposition angle of UWLD track decreased as the corresponding width and fusion depth increased. The microstructures of the deposited metal at a gas flow rate of 10 L/min were composed of the coarse lath α phase in upper region and the acicular martensite α′ with different size scales in middle and bottom regions. With increasing the gas flow rate to 20 L/min, the microstructure was primarily acicular martensite along with a small amount of α phase, and the martensite exhibited a larger grain size and stronger texture. At a gas flow rate of 20 L/min, the deposited process was stable and uniform deposition track without oxidation layer was obtained for UWLD Ti-6Al-4V alloy.
关键词： Ti-6Al-4V alloy,Laser propagation mechanism,Microstructure,Microhardness,Underwater wire-based laser deposition,Geometrical characteristics
更新于2025-09-19 17:13:59
-
Counteracting the Photovoltaic Effect in the Top Intergenerator Part of GaInP/GaAs/Ge Solar Cells
摘要： The “top” intergenerator part situated between the GaInP and GaAs subcells (electric power generators) is analyzed. The shape of the light current–voltage characteristics and the Voc–Jsc (open-circuit voltage–short-circuit current) dependence are examined. It is found that the p+–n+ tunnel heterojunction situated in the “top” intergenerator part can operate as a photoelectric source counteracting the base p–n junctions. In this case, the Voc–Jsc characteristic has a descending part, and a sharp jump can be observed. This undesirable effect becomes weaker with increasing peak current of the tunnel junction.
关键词： current–voltage characteristics,counteracting electromotive force,tunnel diode,photovoltaic characteristics,multiple-junction solar cells,concentrated solar light
更新于2025-09-16 10:30:52