- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Topology Optimization-Based Inverse Design of Plasmonic Nanodimer with Maximum Near-Field Enhancement
摘要： The near-field enhancement factor is one of the most significant parameters to evaluate the performance of plasmonic nanostructures. Numerous efforts have been made to maximize the enhancement factor through optimizing the size, shape, and spatial arrangement of metallic nanostructures with simple geometries, such as disk, triangle, and rod. This work implements topology optimization to inversely design a metallic nanoparticle dimer with the goal of optimizing the near-field enhancement factor in its sub-10 nm gap. By optimizing the material layout within a given design space, the topology optimization algorithm results in a plasmonic nanodimer of two heart-shaped particles having both convex and concave features. Full-wave electromagnetic analysis reveals that the largest near-field enhancement in the heart-shaped nanoparticle dimer is originated from the greatest concentration of surface charges at the nano-heart apex. Inversely designed heart-, bowtie-, and disk-shaped nanodimers are fabricated by using focused helium ion beam milling with a “sketch and peel” strategy, and their near-field enhancement performances are characterized with nonlinear optical spectroscopies at the single-particle level. Indeed, the heart-shaped nanodimer exhibits much stronger signal intensities than the other two structures. The present work corroborates the validity and effectiveness of topology optimization-based inverse design in achieving desired plasmonic functionalities.
关键词： topology optimization,near-field enhancement,plasmonic nanostructures,inverse design,nonlinear optics
更新于2025-09-23 15:21:01
-
Sputtered p-type Cu <sub/>x</sub> Zn <sub/>1-x</sub> S back contact to CdTe solar cells
摘要： As thin film cadmium telluride (CdTe) solar cells gain prominence, one particular challenge is optimizing contacts and their interfaces to transfer charge without losses in efficiency. Back contact recombination is still significant and will prevent CdTe solar technology from reaching its full potential in device efficiency, and transparent back contacts have not been developed for bifacial solar technology or multijunction solar cells. To address these challenges, this study investigates sputtered CuxZn1-xS as a p-type semi-transparent back contact material to thin film polycrystalline CdTe solar cells, at Cu concentrations x = 0.30, 0.45 and 0.60. This material is selected for its high hole conductivity (160 to 2,120 S cm-1), wide optical band gap (2.25 to 2.75 eV), and variable ionization potential (approximately 6 to 7 eV) that can be aligned to that of CdTe. We report that without device optimization, CdTe solar cells with these CuxZn1-xS back contacts perform as well as control cells with standard ZnTe:Cu back contacts. We observe no reduction in external quantum efficiency, low contact barrier heights of approximately 0.3 eV, and carrier lifetimes on par with those of baseline CdTe. These cells are relatively stable over one year in air, with VOC and efficiency of the x = 0.30 cell decreasing by only 1% and 3%, respectively. Using SEM and STEM to investigate the CuxZn1-xS?CdTe interface, we demonstrate that the CuxZn1-xS layer segregates into a bilayer of Cu-Te-S and Zn-Cd-S, and thermodynamic reaction calculations support these findings. Despite its bilayer formation, the back contact still functions well. This investigation explains some of the physical mechanisms governing the device stack, inspires future work to understand interfacial chemistry and charge transfer, and elicits optimization to achieve higher efficiency CdTe cells.
关键词： solar cell back contact design,transparent semiconductors,copper zinc sulfide,solar cell interfaces,CdTe photovoltaics
更新于2025-09-23 15:21:01
-
An Efficient Ultra-Flexible Photo-Charging System Integrating Organic Photovoltaics and Supercapacitors
摘要： Flexible and biocompatible integrated photo-charging devices consisting of photovoltaic cells and energy storage units can provide an independent power supply for next-generation wearable electronics or biomedical devices. However, current flexible integrated devices exhibit low total energy conversion and storage efficiency and large device thickness, hindering their applicability towards efficient and stable self-powered systems. Here, a highly efficient and ultra-thin photo-charging device with a total efficiency approaching 6% and a thickness below 50 μm is reported, prepared by integrating 3-μm-thick organic photovoltaics on 40 μm-thick carbon nanotube/polymer-based supercapacitors. This flexible photo-charging capacitor delivers much higher performance compared with previous reports by tuning the electrochemical properties of the composite electrodes, which reduce the device thickness to 1/8 while improving the total efficiency by 15%. The devices also exhibit a superior operational stability (over 96% efficiency retention after 100 charge/discharge cycles for one week) and mechanical robustness (94.66% efficiency retention after 5000 times bending at a radius of around 2 mm), providing a high-power and long-term operational energy source for flexible and wearable electronics.
关键词： ultra-thin design,photo-charging-capacitors,flexible devices,integration
更新于2025-09-23 15:21:01
-
Nonlinear Analysis Methods Applied on Grid-Connected Photovoltaic (PV) Systems Driven by Power Electronic Converters
摘要： A novel method of analysis is deployed in detail on the basis of nonlinear systems theory with aim to design suitable controllers with guaranteed stability for grid-connected photovoltaic (PV) systems driven by power converters. By this method, all the system nonlinearities are taken into account to allow a reliable analysis in a wide range of operation and to avoid instabilities that as shown in the paper can be occurred by inappropriate design. To this end, firstly a detailed accurate nonlinear dynamic model is presented for the PV system by including a cascade-mode control scheme. Then, taking into account the closed-loop system and incorporating the concept of input-to-state stability (ISS), a rigorous novel stability analysis is developed which achieves to prove asymptotic stability of the desired equilibrium point. A multi-step process is deployed in which the control loops operating in cascade-mode are involved. However, since the cascaded-mode control scheme and analysis is based on the time-scale separation principle, a systematic tuning method is conducted for the accurate gain selection of both inner-loop and outer-loop controllers which is based on the construction of suitable Lyapunov functions. To further validate the overall analysis, experimental results are carried out.
关键词： nonlinear analysis,grid-interaction,Photovoltaic systems,stability,power converter control design
更新于2025-09-23 15:21:01
-
Asymmetric Electron Acceptors for Higha??Efficiency and Lowa??Energya??Loss Organic Photovoltaics
摘要： Low energy loss and efficient charge separation under small driving forces are the prerequisites for realizing high power conversion efficiency (PCE) in organic photovoltaics (OPVs). Here, a new molecular design of nonfullerene acceptors (NFAs) is proposed to address above two issues simultaneously by introducing asymmetric terminals. Two NFAs, BTP-S1 and BTP-S2, are constructed by introducing halogenated indandione (A1) and 3-dicyanomethylene-1-indanone (A2) as two different conjugated terminals on the central fused core (D), wherein they share the same backbone as well-known NFA Y6, but at different terminals. Such asymmetric NFAs with A1-D-A2 structure exhibit superior photovoltaic properties when blended with polymer donor PM6. Energy loss analysis reveals that asymmetric molecule BTP-S2 with six chlorine atoms attached at the terminals enables the corresponding devices to give an outstanding electroluminescence quantum efficiency of 2.3 × 10?2%, one order of magnitude higher than devices based on symmetric Y6 (4.4 × 10?3%), thus significantly lowering the nonradiative loss and energy loss of the corresponding devices. Besides, asymmetric BTP-S1 and BTP-S2 with multiple halogen atoms at the terminals exhibit fast hole transfer to the donor PM6. As a result, OPVs based on the PM6:BTP-S2 blend realize a PCE of 16.37%, higher than that (15.79%) of PM6:Y6-based OPVs. A further optimization of the ternary blend (PM6:Y6:BTP-S2) results in a best PCE of 17.43%, which is among the highest efficiencies for single-junction OPVs. This work provides an effective approach to simultaneously lower the energy loss and promote the charge separation of OPVs by molecular design strategy.
关键词： asymmetric acceptors,molecular design strategies,nonfullerene acceptors,charge separation,organic photovoltaics
更新于2025-09-23 15:21:01
-
The application of image analysis technology in the extraction of human body feature parameters
摘要： With the improvement of living standards, personalized clothing customization has become a trend of people’s apparel demand. The key factor in personalized clothing customization is a three-dimensional human modeling. With the development of image analysis technology, it is possible to use image analysis technology to extract human characteristics. In this paper, two-dimensional human feature regions and characteristic parameter extraction methods of images are used. The backpropagation neural network (BP neural network) is used to curve the three-dimensional human characteristics, and the neck, chest, waist, and buttocks of 22 subjects are verified. The results show that the use of this method can well achieve the extraction of human characteristic parameters.
关键词： Human characteristics,BP neural network,Image analysis,Feature extraction,Computer-aided design (CAD)
更新于2025-09-23 15:21:01
-
Photonic Design, Verification, and Implementation
摘要： The requirement of different sectors such as healthcare, telecommunications, and industry for new systems that will provide higher performance and lower foot-print has triggered the development of many new photonic-based solutions. A key aspect of the development of an optical system is the design and verification before its production to reduce failure and, as consequence, the time-to-market. There are commercial software solutions able to simulate and to analyze the packaging of optical systems, photonic integrated circuits (PICs) based devices, transmission systems & networks, and fiber-optic lasers & amplifiers. Also, it is possible to take into account thermal and mechanical issues by multiphysics simulations. In this article, we explore the different available solutions to simulate your optical design before the production at the component level including free-form optics and photonic integrated circuits (PICs) and also at the system level.
关键词： photonic integrated circuits,multiphysics simulations,photonic-based solutions,optical system design
更新于2025-09-23 15:21:01
-
Design and investigation of cooling system for high-power LED luminaire
摘要： This paper is concerned with development of cooling system for high-power LED luminaire, including design, simulation, production and investigation. Dimension, shape, and topology optimization algorithms and their program realization are developed with the use of MathCad. Thermal design by Comsol Multiphysics showed that the system on the base of heat pipes is the most effective system for cooling of high-power LED luminaire. The numerical simulation was employed to valid the designed-in engineering solution of cooling system for high-power LED luminaire under elevated temperature operating conditions and different orientation in space. In accordance to simulation data cooling system on the base of heat pipes is designed. Theoretical results are well validated by experimental data and numerical simulation and can be widely utilized for designing of cooling system related to various LED products.
关键词： Cooling system,Heat pipe,Thermal design,High-power LED luminaire
更新于2025-09-23 15:21:01
-
[Communications in Computer and Information Science] Advances in Computing and Data Sciences Volume 905 (Second International Conference, ICACDS 2018, Dehradun, India, April 20-21, 2018, Revised Selected Papers, Part I) || Assessing the Performance of CMOS Amplifiers Using High-k Dielectric with Metal Gate on High Mobility Substrate
摘要： With the increase in demand for high-performance ICs for both memory and logic applications, scaling has been continued down to 14 nm node. To meet the performance requirements, high-k dielectrics such as HfO2, ZrO2 have replaced SiO2 in the conventional MOS structure for sub-45 nm node. Correspondingly, the polysilicon gate electrode has been replaced by metal gate electrode in order to enable integration with high-k. Furthermore, the standard silicon substrate has been replaced by high mobility substrate in order to obtain desired transistor performance. While the fabrication technology for CMOS has advanced rapidly the traditional design tools used for designing circuits continues to use conventional MOS structure and their properties. This paper aims to analyze frequency response of CMOS common source ampli?er(CSA) and di?erential ampli?er by simulating in MATLAB using metal gate/high-k/Ge structure and to compare with traditionally used ampli?er design using standard MOS structure.
关键词： CMOS - Complementary Metal Oxide Semiconductor,EOT - E?ective Oxide Thickness,CSA - Common Source Ampli?er,UGB - Unity Gain Bandwidth,High-k dielectrics based ampli?er design
更新于2025-09-23 15:21:01
-
Effect of Laser Beam Conditioning on Fabrication of Micro-Channels in Al <sub/>2</sub> O <sub/>3</sub> Bio-ceramics Using Nd:YAG Laser
摘要： In the present study, laser micro-milling tests were carried out to fabricate micro-channels on Alumina bio-ceramics (Al2O3), using a Q-Switched 30W Nd:YAG pulsed laser. A systematic approach based on a full factorial Design of Experiment (DoE) has been successfully applied with the aim to detect which and how the key input laser process parameters affect the channel dimensional accuracy. The examined process parameters were the laser beam scanning speed, the pulse frequency and the pulse intensity. Optical microscope was used to analyze the channel geometries responses (i.e. channel's top width, bottom width, depth, and taper wall angle). Moreover, mathematical models for predicting the micro-channel geometries are successfully proposed for controlled micro-milling of micro-channels in Al2O3. Results reveal that, the change of scanning speed and laser intensity significantly affected the ablated channel’s geometries. Further it is observed that the channel depth and width increase linearly with increasing of laser intensity and decreasing of scanning speed and not much affected by changing of pulse frequency. Finally, the experimental results bear a good agreement with the proposed prediction models.
关键词： micro-channels,Nd:YAG laser,Al2O3 bio-ceramics,Design of Experiment,Laser micro-milling
更新于2025-09-23 15:21:01