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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Impact of Relaxation Processes on Features of Laser Dyes
摘要： A method to precisely determine the quantum efficiency and primary photocurrent in avalanche photodiodes (APDs) is presented based on a linear relationship between excess noise factor F and gain, M. The new method is used to accurately compare performance of modern APD designs when nonlocal impact ionization effects govern the relationship between noise and gain.
关键词： Avalanche photodiode (APD),near-infrared detection,impact ionization,excess noise factor
更新于2025-09-23 15:19:57
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Design and Implementation of 150 W AC/DC LED Driver with Unity Power Factor, Low THD, and Dimming Capability
摘要： This paper presents the implementation of a two-stage light-emitting diode (LED) driver based on commercial integrated circuits (IC). The presented LED driver circuit topology, which is designed to drive a 150 W LED module, consists of two stages: AC-DC power factor correction (PFC) stage and DC/DC power converter stage. The implementation of the PFC stage uses IC NCP1608, which uses the critical conduction mode to guarantee a unity input power factor with a wide range of input voltages. The DC/DC power converter with soft-switching characteristics for the entire load range uses IC FLS2100XS. Furthermore, the design of an electromagnetic interference (EMI) filter for the LED driver and the dimming control circuit are discussed in detail. The hardware prototype, an LED lighting system, with a rated power of 150 W/32 V from a nominal 220 V/50 Hz AC voltage supply was tested to show the effectiveness of the design. The presented LED driver was tested for street lighting, and the experimental results show that the power factor (PF) was higher than 0.97, the total harmonics distortion (THD) was lower than 7%, and the efficiency was 91.7% at full load. The results prove that the performance of the presented LED driver complies with the standards: IEC61000-3-2 and CIRSP 15:2009.
关键词： EMI filter,power factor correction,LED driver,LLC resonant converter
更新于2025-09-23 15:19:57
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Altering alkyl-chains branching positions for boosting the performance of small-molecule acceptors for highly efficient nonfullerene organic solar cells
摘要： The emergence of the latest generation of small-molecule acceptor (SMA) materials, with Y6 as a typical example, accounts for the surge in device performance for organic solar cells (OSCs). This study proposes two new acceptors named Y6-C2 and Y6-C3, from judicious alteration of alkyl-chains branching positions away from the Y6 backbone. Compared to the Y6, the Y6-C2 exhibits similar optical and electrochemical properties, but better molecular packing and enhanced crystallinity. In contrast, the Y6-C3 shows a significant blue-shift absorption in the solid state relative to the Y6 and Y6-C2. The as-cast PM6:Y6-C2-based OSC yields a higher power conversion efficiency (PCE) of 15.89% than those based on the Y6 (15.24%) and Y6-C3 (13.76%), representing the highest known value for as-cast nonfullerene OSCs. Prominently, the Y6-C2 displays a good compatibility with the PC71BM. Therefore, a ternary OSC device based on PM6:Y6-C2:PC71BM (1.0:1.0:0.2) was produced, and it exhibits an outstanding PCE of 17.06% and an impressive fill factor (FF) of 0.772. Our results improve understanding of the structure-property relationship for state-of-the-art SMAs and demonstrate that modulating the structure of SMAs via fine-tuning of alkyl-chains branching positions is an effective method to enhance their performance.
关键词： power conversion efficiency,fill factor,small molecular acceptor,alkyl-chain branching position,organic solar cell
更新于2025-09-23 15:19:57
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Increased efficiency of 23% for CIGS solar cell by using ITO as front contact
摘要： In this paper, a CIGS material based solar cell structure is proposed. The ef?ciency of the designed structure is improved by considering ITO (Indium Tin Oxide) as a front contact. The detailed analysis of the device is carried out thoroughly using SILVACO ATLAS. Various design parameters such as open-circuit voltage (Voc), the voltage at maximum power density, short circuit current density (Jsc), maximum output power (Pm), and ?ll factor (FF), are calculated. CIGS solar cell with ITO as a front contact gives an improved ef?ciency of 23.074%. Thus, the proposed solar cell is a suitable candidate for ultra-high ef?ciencies.
关键词： Fill factor,Ef?ciency,ITO,CIGS,Solar cell,TCAD
更新于2025-09-23 15:19:57
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Design and optimization of perovskite plasmonic nano-laser for operation at room temperature
摘要： This work presents the design and optimization of a cascade nano-laser using CH3NH3PbI3 perovskite. Due to increasing threshold gain with decreasing device size and high Auger losses, the use of perovskite as the active medium in the cascade nano-laser was proposed, as the material possesses a high emission rate in the visible wavelength region, with relative ease of device fabrication. By optimizing the thickness of the perovskite, its width, and the thickness of the silica used, photonic and plasmonic modes were created, which were further considered to permit the generation of lasing, using their respective Purcell factors. The pump wavelength considered was 400 nm, with the laser emission then at 537 nm. For suitability of plasmonic lasing, a Purcell factor FP of 1.22 is reported here, with no possibility for photonic lasing due to its FP value being less than 1 in this design. However, mode-crossing effects were observed in the plasmonic mode at λ = 400 nm for two designs: at a silica thickness of 27.5 nm with perovskite thickness and width of 100 and 300 nm, respectively, and at a silica thickness of 30 nm with perovskite thickness and width of 95 and 300 nm, respectively. These mode-crossing effects can be further analyzed to use these devices in the design of potential new sensor systems, mainly for gas and chemical sensing, exploiting the refractive index sensing capability as a means to determine the concentration of the gases, or other chemicals, under study.
关键词： room temperature,plasmonic nano-laser,Purcell factor,perovskite,mode-crossing effects
更新于2025-09-23 15:19:57
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Efficiency Measurement and Factor Analysis of Chinaa??s Solar Photovoltaic Power Generation Considering Regional Differences Based on a FAHPa??DEA Model
摘要： Driven by the transformation of the energy structure, China’s photovoltaic (PV) power generation industry has made remarkable achievements in recent years. However, there are more than 30 regions (cities/provinces) in China, and the economic, policy, technological, and the environmental conditions of each region are significantly different, which leads to a huge discrepancy in PV power generation efficiency. To address the imbalance in the development of PV industry, first, this paper employed the integrated fuzzy analytic hierarchy process–data envelopment analysis (FAHP–DEA) model to evaluate the PV power generation efficiency of 30 regions in China. Second, Tobit regression model was used to examine the effects of 9 potential influencing factors. Third, a concrete analysis was conducted, and discussion based on the efficiency rankings and regression results was made. Additionally, the FAHP–DEA model proposed in this study can also be applied to the efficiency evaluation issues of other types of renewable energy.
关键词： photovoltaic,factor analysis,fuzzy analytic hierarchy process (FAHP),efficiency measurement,data envelopment analysis (DEA)
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Controlling Silicon Bottom Cell Lifetime Variance in II-VI/Si Tandems
摘要： This paper provides an overview of the main features of several bibliometric indicators which were proposed in the last few decades. Their pros and cons are highlighted and compared with the features of the well-known impact factor (IF) to show how alternative metrics are speci?cally designed to address the ?aws that the IF was shown to have, especially in the last few years. We also report the results of recent studies in the bibliometric literature showing how the scienti?c impact of journals as evaluated by bibliometrics is a very complicated matter and it is completely unrealistic to try to capture it by any single indicator, such as the IF or any other. As such, we conclude that the adoption of more metrics, with complementary features, to assess journal quality would be very bene?cial as it would both offer a more comprehensive and balanced view of each journal in the space of scholarly publications, as well as eliminate the pressure on individuals and their incentive to do metric manipulation which is an unintended result of the current (mis)use of the IF as the gold standard for publication quality.
关键词： impact factor,popularity indicators,prestige indicators,Eigenfactor,research evaluation,journal ranking,Bibliometrics
更新于2025-09-23 15:19:57
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Out-of-Plane Nanoscale Reorganization of Lipid Molecules and Nanoparticles Revealed by Plasmonic Spectroscopy
摘要： Lipid bilayers assembled on solid substrates have been extensively studied with single-molecule resolution as the molecules diffuse in 2D, however the out-of-plane motion is typically ignored. Here we present sub-nanometer out-of-plane diffusion of nanoparticles attached to hybrid lipid bilayers (HBLs) assembled on metal surfaces. The nanoscale cavity formed between Au nanoparticle and Au film provides strongly-enhanced optical fields capable of locally probing HBLs assembled in the gaps. This allows us to spectroscopically resolve the nanoparticles assembled on bilayers, near edges, and in membrane defects, showing the strong influence of charged lipid rafts. Nanoparticles sitting on the edges of the HBL are observed to flip onto and off the bilayer, with flip energies of 10 meV showing how thermal energies dynamically modify lipid arrangements around a nanoparticle. We further resolve the movement of individual lipid molecules by doping the HBL with low concentrations of Texas-red (TxR) dye-labeled lipids.
关键词： Purcell factor,Plasmonics,Single-molecule,Nano-assembly,Nanocavities,Lipid bilayers
更新于2025-09-23 15:19:57
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Device performance of standard strip, slot and hybrid plasmonic ??-ring resonator: a comparative study
摘要： In this paper, we presented three μ-ring resonator structures based on the standard strip, slot and hybrid plasmonic waveguides based on the SOI platform. A standard strip waveguide is formed by depositing a silicon core on a silica substrate. Whereas the slot waveguide is tailored by keeping a narrow air gap between two silicon strip waveguides. Finally, the hybrid plasmonic waveguide is composed of Metal-Air-Silicon structure, where the E-field is significantly enhanced in the narrow air gap. The ring radius is kept at 1.5 μm for the three designs. The transmission spectrum and E-field distribution of these structures are simulated using the finite element method (FEM). Silicon strip waveguide-based ring resonators are easy to fabricate but their sensitivity is quite low as compared to the other two designs. μ-ring resonator based on hybrid plasmonic waveguide shows the best sensitivity of 333.3 nm/RIU. While, slot waveguide based μ-ring resonator showed the best performance in the quality factor, the figure of merits and limit of detection. We believe that this comparative study will facilitate the researchers to choose the suitable waveguide design for ring resonators depending on their preferred application and fabrication technology available.
关键词： Conventional ring resonator,hybrid plasmonic ring resonator,sensitivity,figure of merit,limit of detection,Q-factor,slot ring resonator
更新于2025-09-23 15:19:57
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Effects on surface-enhanced Raman scattering from copper nanoparticles synthesized by laser ablation
摘要： In this work, we report the synthesis of Cu nanoparticles (NPs) by laser ablation technique using 532 nm and 1064 nm wavelength in ethylene glycol. The optical and morphological studies of as-prepared NP colloids were characterized using UV–Visible absorption , photoluminescence spectrometers and transmission electron microscope (TEM) techniques. Cu NPs synthesized at 532 nm and 1064 nm were spherical with an average size of 3.2 ± 0.1 nm and 4.3 ± 0.1 nm respectively. Furthermore, surface-enhanced Raman scattering (SERS) studies were performed on methylene blue (MB) using Cu NPs as SERS platform. In addition, the effects of size, shape and localized surface plasmon resonance (LSPR) of Cu NPs as well as the Raman excitation wavelength used for SERS measurement were investigated and discussed to give insight into the factors affecting their SERS enhancement factor.
关键词： enhancement factor,SERS,optical properties,Cu NPs
更新于2025-09-23 15:19:57