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Study of Electrophotophysical Characteristics of IR Photodetectors Based on PbS Colloidal Quantum Dots
摘要： The electrophotophysical characteristics of laboratory samples of IR photodetectors obtained by dip coating of PbS colloidal quantum dots with the subsequent exchange of oleic acid molecules that compose their ligand shell by S2? ions have been studied.
关键词： thin layers,electrophysical characteristics of layers,spectral and luminescent properties,dip-coating method,near infrared region,PbS colloidal quantum dots,ligand exchange,IR photodetectors
更新于2025-09-16 10:30:52
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Solar Engineering of Thermal Processes, Photovoltaics and Wind || Radiation Characteristics of Opaque Materials
摘要： This chapter begins with a detailed discussion of radiation characteristics of surfaces. For many solar energy calculations only two quantities are required, the solar absorptance and the long-wave or infrared emittance, usually referred to as just absorptance and emittance. Although values of these two quantities are often quoted, other radiation properties may be the only available information on a particular material. Since relationships exist between the various characteristics, it may be possible to calculate a desired quantity from available data. Consequently, it is necessary to understand exactly what is meant by the radiation terms found in the literature, to be familiar with the type of information available, and to know how to manipulate these data to get the desired information. The most common type of data manipulation is illustrated in the examples, and readers may wish to go directly to Section 4.5.
关键词： selective surfaces,solar energy,infrared emittance,solar absorptance,radiation characteristics
更新于2025-09-16 10:30:52
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SILAR Controlled CdS Nanoparticles Sensitized CdO Diode Based Photodetectors
摘要： In this research, we have produced Al/CdS nanoparticles-CdO/p-si/Al photodetetor and investigated its optical and electrical characteristics for various optoelectronic applications. The CdO thin film was covered by using sol-gel spin coating method onto the silicon, followed by CdS nanoparticles constitution by the help of SILAR technique. In order to examine the morphological and optical characteristics of fabricated photodetector, the field emission scanning electron microscopy and UV-Vis spectroscopy were utilized, and the band gap of the prepared film was determined as 2,17 eV with the help of these analyzes. The current behavior against the varying voltage values were investigated for the different intensities of solar light conditions and the significant diode parameters were computed by the use of this measurements. As a result of this computation, the barrier height value was found to be 0.49 eV while the ideality factor value was 3.2, and the photoresponse of the photodetector was measured as approximatelly 2.65 × 103. Besides, the transient photocurrent and photocapacitance charactersitics were examined for distinct light conditions. Finally, the interface states were calculated from the capacitance/conductance–voltage (C/G–V) measurements.
关键词： Optical characteristics,SILAR method,Sol-gel method,CdO thin film,Electrical characteristics,CdS nanoparticles
更新于2025-09-12 10:27:22
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A Comprehensive Study on a Stand-Alone Germanium (Ge) Solar Cell
摘要： The effect of temperature on the performance parameters [short-circuit current density (JSC), open-circuit voltage (VOC), ?ll factor (FF), and conversion ef?ciency (g)] of stand-alone germanium (Ge) solar cells has been theoretically investigated. Although JSC increased with increasing temperature, g decreased due to a decrease in VOC and the associated decrease in the FF. The performance parameters JSC, VOC, FF, and g of a fabricated stand-alone Ge solar cell were determined from current–voltage (I–V) measurements. The signi?cant differences between the obtained theoretical and experimental data may be related to both the use of idealized cases in the theoretical studies and the loss mechanisms considered to adversely affect the performance of the fabricated stand-alone Ge solar cell.
关键词： current–voltage characteristics,Temperature,germanium solar cell,solar cell performance
更新于2025-09-12 10:27:22
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Study on electronic blocking layer of 403 nm GaN-based vertical cavity surface emitting lasers
摘要： In order to obtain good optical characteristics in the GaN-based vertical-cavity surface-emitting laser (VCSEL), different kinds of AlGaN electron blocking layers (EBL) were introduced. These were inserted coherently near the active region to limit electron leakage into the p-doped side. The research was conducted by photonic integrated circuit simulator in three-dimensional (PICS3D). The simulated results reveal that an EBL can improve the optical characteristics of a VCSEL effectively. All the advantages are due to a reduction in the electron leakage in the quantum wells. While the voltage of the five-layer EBLs LD is lower than the voltage of the seven-layer EBLs LD, the output power of the two is approximately the same, so the five-layer EBLs is the best choice for comprehensive structure analysis as the epitaxial structure can be grown more easily on it.
关键词： PICS3D,optical characteristics,GaN-based VCSEL,electron blocking layer
更新于2025-09-12 10:27:22
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Microwave Vortex Imaging Based on Dual Coupled OAM Beams
摘要： This paper investigates electromagnetic (EM) vortex imaging based on dual coupled orbital angular momentum (OAM) beams. An OAM-generating scheme is proposed to generate radio waves carrying various dual coupled OAM at the X-frequency band and the experimental results of radar imaging in an anechoic chamber are illustrated for the first time. The uniform circular array (UCA) is exploited to generate dual coupled OAM beams and the radiated fields are presented by both theoretical analysis and full-wave EM simulation. Subsequently, the mathematical imaging model is established and the target reconstruction method is proposed. The relative imaging error (RIE) is introduce to evaluate the imaging performance. The imaging results indicate that the proposed method can have a better performance than EM vortex imaging without OAM-multiplexing and save half time of OAM beams transmitting. Moreover, the imaging experimental results in the anechoic chamber validate the effectiveness of the proposed method. This paper applies OAM-multiplexing beams to radar imaging and improves the vortex imaging efficiency, which can benefit the applications of OAM beams and the design of OAM-based radar systems.
关键词： dual coupled OAM beam,mode characteristics analysis,orbital angular momentum,Electromagnetic vortex imaging
更新于2025-09-12 10:27:22
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[IEEE 2019 8th International Symposium on Next Generation Electronics (ISNE) - Zhengzhou, China (2019.10.9-2019.10.10)] 2019 8th International Symposium on Next Generation Electronics (ISNE) - Simulation based IV Characteristics Analysis of GaAs and InP Solar Cell
摘要： This paper presents the simulation of current- and voltage characteristics of III-V semiconductors, Gallium Arsenide (GaAs) and Indium Phosphide (InP) homojunction solar cell under standard illumination AirMass-1.5D spectrum using MicroTec-simulator. The IV characteristics curves signify the use of GaAs with 86.22% Fill Factor (FF) and 28.5% efficiency than InP with 82.48% FF and 24% efficiency in photovoltaic (PV) unit. The influence of change in doping profile and temperature of GaAs solar cell is simulated for improving the device performance. Due to the substantial increase in base doping concentration, increase in Maximum Power Output (Pm), FF and efficiency have been noticed. We have observed 0.684% per °C decrease in Pm along with 0.1% per °C decrease in efficiency from the GaAs photovoltaic cell.
关键词： Maximum Power Output,IV characteristics,solar cell,Photovoltaic
更新于2025-09-12 10:27:22
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Existence of an Infinite Spectrum of Damped Leaky TE Waves in an Open Inhomogeneous Cylindrical Metal–Dielectric Waveguide
摘要： We consider the problem about leaky waves in an inhomogeneous waveguide structure. This problem is reduced to a boundary value problem for the longitudinal components of the electromagnetic ?eld in Sobolev spaces. A variational problem statement is used to determine the solution. The variational problem is reduced to studying an operator function. The properties of this operator function necessary for analyzing its spectral characteristics are investigated. Theorems about the discreteness of the spectrum and the distribution of the characteristic numbers of the operator function on the complex plane are proved. The existence of in?nitely many damped leaky waves in a cylindrical waveguide is established.
关键词： operator function,spectral characteristics,Sobolev spaces,damped leaky waves,leaky waves,inhomogeneous waveguide
更新于2025-09-12 10:27:22
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Efficient Method of Fabricating Polymeric Solar Cells in Multilayered Configuration Using Electrospray
摘要： Electrospray deposition (ESD) for the fabrication of multilayered (ML) bulk heterojunction polymeric solar cells via direct/inverted configurations was investigated. The active layer heterojunction (P3HT/PCBM) is deposited both in single and multilayered architectures. In ML configuration, the P3HT/PCBM blend film is sandwiched between thin donor (P3HT) and acceptor (PCBM) layers. In ZnO-based inverted solar cells, ZnO film synthesized by sol–gel process was deposited on ITO substrate using spin coatinng. Solar cells were fabricated via ESD and spin coating and the device’s performance parameters were compared. Higher efficiency was obtained in the case of (ML) ESD device (direct structure). Post thermal treatment showed that ESD devices exhibit a power conversion efficiency (PCE) of 1.85% ML and 1.64% SL in direct structure while in the case of inverted structure PCEs of 1.30% ML and 0.82% SL were obtained as compared to 1.64% from the spin coated device at 120°C. The ML ESD devices have shown an overall efficiency enhancement of 13% (direct) and 58% (inverted) over the single layer (SL) ESD devices. The enhanced performance in ML devices is because there is a spatially uninterrupted pathway to the charge carrier transport towards their respective electrodes.
关键词： J–V characteristics,Polymeric solar cells,ZnO based Inverted organic solar cells,electrospray deposition,multilayered films
更新于2025-09-12 10:27:22
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Impact of Bypass Diode Forward Voltage on Maximum Power of a Photovoltaic System under Partial Shading Conditions
摘要： The maximum power of a photovoltaic system can reduce significantly under partial shading conditions. Bypass diodes can be used in photovoltaic systems to bypass the shaded photovoltaic modules during partial shading. The bypass diode possesses a forward voltage that introduces a voltage drop in the photovoltaic system upon activation. Therefore, the maximum power of a photovoltaic system can reduce further during partial shading due to the forward voltage of the bypass diode. This paper presents an investigation into the effect of bypass diode forward voltage on the maximum power of a photovoltaic system under partial shading conditions. The results indicated that the forward voltage of the bypass diode did not necessarily decrease the maximum power of the photovoltaic system. This depends on whether the maximum power is delivered at a lower or higher voltage. When the maximum power is delivered at a higher voltage, it is insusceptible to the forward voltage. Conversely, when the maximum power is delivered at a lower voltage, it is susceptible to the forward voltage. In the worst-case scenario, the forward voltage of the bypass diode reduced the maximum power of the photovoltaic system by 16.48%, which was already subject to partial shading loss.
关键词： P-V characteristics,solar energy,Photovoltaic,bypass diode,partial shading
更新于2025-09-12 10:27:22