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Modeling and design for low‐cost multijunction solar cell via light‐trapping rear texture technique: Applied in InGaP/GaAs/InGaAs triple junction
摘要： To realize high efficiency in parallel with low cost, a light‐trapping rear texture was proposed to be implemented in substrate‐free thin‐film multijunction (MJ) cells. A detailed‐balance theory was formulated taking account of the finite light absorption in thin subcells. Such presented absorption model is general and useful to optimize the subcell thickness for MJ solar cells with light‐trapping design. It is applied for InGaP/GaAs/InGaAs triple‐junction solar cells to simulate subcell photocurrents and to obtain the current‐matching (minimum requisite) subcell thicknesses combinations. Furthermore, the detailed‐balance conversion efficiency was estimated for both radiative limit and the cases with below‐unity internal radiative efficiency. For InGaP/GaAs/InGaAs MJ cells with InGaP subcell thickness less than 600 nm, adding a random‐textured rear reflector can enhance light absorption so significantly that over 90% of InGaAs‐cell thickness and even 50% of GaAs‐cell thickness would be cut without any penalty in conversion efficiency, compared with the subcell thicknesses in traditional MJ cells with flat rear reflectors. Additionally, the thickness combination, (InGaP, GaAs, and InGaAs) = (450 nm, 333 nm, and 26 nm), is recommended to achieve both high conversion efficiency and low material cost. This work provides a very important theoretical guidance for the development on low‐cost and high‐efficiency MJ devices.
关键词： detailed‐balance limit,low cost,multijunction solar cell,texture surface,light trapping
更新于2025-09-12 10:27:22
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Double-sided pyramid texturing design to reduce the light escape of ultrathin crystalline silicon solar cells
摘要： Reducing the light absorption loss of ultrathin crystalline silicon (c-Si) solar cells is significant to achieve high photocurrent density and photoelectric conversion efficiency. Here, we designed and simulated ultrathin c-Si cells with front pyramids and double-sided pyramids. By adjusting the shape of pyramids, the maximum photocurrent densities reach 36.23 and 37.71 mA/cm2 for the cells with front pyramids and double-sided pyramids, respectively. The reflectivity spectrum indicates that the double-sided pyramidal architecture remarkably suppresses light escape and then enhances the light absorption in long wavelength range, which makes the absorption approach the Yablonovitch limit. The calculated conversion efficiencies of planar, front and double-sided textured cells are 16.94%, 19.65% and 20.45% respectively. Additionally, the difference between randomly and periodically textured cells was investigated and the results show that although the randomly front pyramid texture has a better light absorption in the range of 900–1200 nm, the periodically double-sided pyramids texture exhibit almost the same light absorption in the whole range as the random one. Besides, the solar cells with double-sided pyramids show extremely small angular dependence of incident light. Thus, the double-sided light trapping structure designed in the present work provides an alternative pathway to improve the performance of ultrathin c-Si cells.
关键词： Conversion efficiencies,Double-sided texture,Angular dependence,Ultrathin c-Si solar cells,Photocurrent density
更新于2025-09-12 10:27:22
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Laser dimple texturing – applications, process, challenges, and recent developments: a review
摘要： Laser dimple texturing has been a surge in the surface to surface contact applications like the cutting tool/workpiece interaction, piston-cylinder assembly, bearings, prosthetic hip & knee joints, blanking punch- die assembly, etc. to control the friction and wear between the interactions. In this article, the first part presented about a broad literature review on an effect of dimple texture in various industrial applications like bio-implant components and cutting tools. In the second part, detailed information has discussed on a process of laser dimple texturing and influence of laser process parameters such as laser wavelength, laser energy, number of pulses, pulse duration and focal distance on dimple geometry. The third part describes a comprehensive literature review on challenges/limitations of laser dimple texturing process like heat affected zone, tensile residual stresses, bulges around the dimple, etc. Finally, in the fourth part, proper attention has given on recent developments like laser shock peen texturing, laser texturing under water and post-processing techniques to overcome the limitations of laser surface texturing process.
关键词： Friction,Hip & knee joints,Wear,Cutting tool,Laser peen texturing,Heat affected zone,Laser dimple texture
更新于2025-09-12 10:27:22
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Applications of Laser-Induced Breakdown Spectroscopy for Soil Analysis, Part I: Review of Fundamentals and Chemical and Physical Properties
摘要： Laser-induced breakdown spectroscopy (LIBS) has become a prominent analytical technique in recent years for real-time characterization of soil properties. However, only a few studies of soil chemical and physical properties have been reported using LIBS until recently. The aims of this article are to: (1) provide the basic principles of LIBS for soil analysis and (2) present the use of LIBS for soil pH, soil texture, and humification degree of soil organic matter (SOM). The second article will cover soil classification and soil elemental analysis, including plant nutrients, carbon (C), and toxic elements. LIBS is a multi-element analytical technique based on atomic spectroscopy that employs a high-energy laser pulse focused onto a sample surface to create a transient plasma. It is a spectroscopic analytical technique that requires very little or no sample preparation, examines each sample in seconds, and offers a flexible platform for the examination of a broad array of elements in the sample. LIBS also can be used to infer soil chemical and physical properties if a relationship exists between the chemical composition and the soil properties. With proper calibration, LIBS has a great potential for real-time in-field soil analysis and precision farming that could lead to improved soil management and agricultural production, and reduced agricultural environmental impacts.
关键词： humification degree of soil organic matter,soil texture,precision agriculture,soil sensing,soil analysis,soil pH
更新于2025-09-11 14:15:04
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Enhance the solar cell efficiency by reduction of reflection losses
摘要： The enhancement of the solar cell efficiency field has been achieved in many methods due to the different factors and conditions that led to loss the solar energy .This work deals with the increasing of the efficiency of solar cell that made of single crystalline silicon .This increment achieved by the reduction of biggest type of losses of the conversion efficiency named reflection . by using two methods first ; forming grooves on the surface using pulse Nd:YAG laser with max energy 1J and pulse width 10ns, using the fast and accurate movement of the 3D optical galvo mirror scanning system to form the grooves , the second method was by deposition nanomaterials as Silver (Ag) and Cadmium telluride (CdTe) to constitute an antireflection layer for the incident solar spectrum . The effect of antireflection layer material type and the effect of incident light angle on the reflection had been studied in this work .The reflectance had been measured by a system designed and built to give the reflection for angles ranged 0 – 180 degree controlled by Microcontroller. The result inducate that increase in conversion efficiency was 28.3% for Ag/Si , and 32.9% for CdTe/Si than the original efficiency of Si solar cell.
关键词： silicon solar cell,reflectance,laser texture,nanoparticles,antireflection surfaces
更新于2025-09-11 14:15:04
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Variation of Surface Topography in Laser Powder Bed Fusion Additive Manufacturing of Nickel Super Alloy 625
摘要： This document provides details on the files available for download in the dataset “Variation of Surface Topography in Laser Powder Bed Fusion of Nickel Super Alloy 625.” The following sections provide details on the experiments, methods, and data files. The experiment detailed in this document methodically varies part position and surface orientation relative to the build plate and relative to the recoater blade. This dataset provides surface height data for analysis and development of correlations by the greater research community.
关键词： additive manufacturing,focus variation,IN625,surface texture,surface topography,nickel super alloy 625,laser powder bed fusion
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Powerful topographic analyzing method using fast Fourier transform for c-Si solar cells and advanced technologies
摘要： Roughness and texture analyses are an important topic for process development of high efficiency solar cells. Especially, strong improvement in Jsc was obtained by proper texturing of c-Si solar cells, which helped enhancing its infrared response. Usual pyramid size analysis relies on microscopy technique followed by image processing. One of the critical challenges to obtain an appropriate pyramid size distribution is to remove the initial contribution of background roughness, which is usually done by subtracting a polynomial background. This method holds strong limitation on physical meaning since the arbitrary chosen degree of the polynomial background will influence size distribution and can even provoke large errors. In this work, we present a method allowing to separate the contributions of different spatial frequencies and to filter the ones that need to be studied by applying Fast Fourier Transform (FFT). MountainsMap? software was used to study the roughness through a FFT treatment. A FFT spectrum was obtained in which selected frequencies were extracted to remove the noise and interferences from the initial confocal image. The resulted filtered topography image was obtained by the inverse FFT and analyzed to obtain the structural, morphological and geometrical characteristics of the surface. This methodology – applicable to several characterization methods – is particularly efficient when used with laser confocal scanning microscopy and opens the way to fast, automatic, accurate and non-destructive analysis that can be repeated at different positions of a sample with high throughput to enable statistical analysis.
关键词： topography analysis,Fast Fourier Transform,c-Si solar cells,roughness,texture
更新于2025-09-11 14:15:04
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The effect of laser surface texturing to inhibit stick-slip phenomenon in sliding contact
摘要： Stick-slip phenomenon in some mechanical structures, especially in machine tools, should be eliminated or inhibited, otherwise the vibration will occur and the position error will inevitably be obtained. In this study, different kinds of surface textures were carried out on the lower samples of the pin-on-disk contact. The starting process of the machine tools was simulated on an Rtec-Multi-Function Tribometer. The stick-slip phenomenon was observed in each kind of samples. However, the stick-slip phenomenon of smooth sample is larger than that of the textured samples. The bulge-textured surface shows excellent anti-stick-slip effect, and the critical stick-slip speed of bulge-textured surface is 95.9% lower than that of the smooth surface. Simultaneously, the anti-stick-slip effect of bulge-textured surface is superior to that of the dent-shaped texturing surface. What’s more, when the amount of lubricating oil is 15 mL, the standard deviation values of friction coefficient and critical speed of stick-slip phenomena (rotational speed when the standard deviation of friction coefficient is abrupt) are the lowest at different rotational speeds. It can be predicted that the bulge textures and adequate amount of lubricating oil (15 mL) can eliminate stick-slip phenomenon when processed in the surface of the machine tool because the bulge textures and adequate amount of lubricating oil can improve frictional state effectively and avoid the slip of the contact surface.
关键词： machine tool,laser surface texturing,Stick-slip phenomenon,critical stick-slip speed,bulge texture
更新于2025-09-11 14:15:04
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P‐3.3: High Definition OLED‐on‐Silicon Micro‐display Based on Human Visual Characters
摘要： As users demand higher refresh rates and frame rates, the amount of data in the virtual reality field is also growing. There is a large visual perception redundancy in the image source transmitted by the micro-display system. In this paper, an OLED-on-silicon micro-display system based on human visual characters is designed to solve the problem of high data bandwidth transmission in head-mounted virtual reality applications. The experimental results show the multi-resolution image fusion compression algorithm based on the visual perception of human eye has the good data compression ratio. The proposed method meets the visual perception of the human eye. It has good rendering quality, which meets real-time rendering requirements of the OLED-on-silicon micro-display in the virtual reality embedded environment.
关键词： Micro-display,Data transmission,Human visual characters,Texture pyramid
更新于2025-09-11 14:15:04
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Effect of Surface and Subsurface Defects on Fatigue Behavior of AlSi10Mg Alloy Processed by Laser Powder Bed Fusion (L-PBF)
摘要： The fatigue behaviour of an AlSi10Mg alloy processed by laser powder bed fusion (L-PBF) and subjected to different surface finishing processes was investigated paying special attention to the residual defects on the surface and the dominant fatigue failure mechanisms. Roughness measurements and qualitative surface morphology analysis showed smooth surfaces in the case of vibro-finishing and machining followed by polishing. The fatigue performance did not reveal to be directly related to surface roughness, but residual intrusions left on the finished surfaces. Post-mortem analysis showed single- or multiple-crack nucleation from pores opened on the surface, un-melted powders, or spatters considered as typical L-PBF defects. A fatigue limit of 195 MPa for machined and polished samples was obtained by substantial removal of surface and subsurface defects.
关键词： surface texture,laser powder bed fusion,AlSi10Mg alloy,surface finishing,fatigue strength
更新于2025-09-11 14:15:04