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21.
As a critical component of grid security, secure and efficient grid authentication needs to be well addressed. However, the most widely accepted and applied grid authentication is based on public key infrastructure （PKI） and X.509 certificates, which make the system have low processing efficiency and poor anti-attack capability. To accommodate the challenge of grid authentication, this article aims at designing a secure and efficient method for grid authentication by employing identity-based cryptography （IBC）. Motivated by a recently proposed secure and efficient identity-based encryption （IBE） scheme without random oracles, an identity-based signature （IBS） scheme is first proposed for the generation of private key during grid authentication. Based on the proposed IBS and the former IBE schemes, the structure of a novel grid authentication model is given, followed by a grid authentication protocol described in detail. According to the theoretical analysis of the model and the protocol, it can be argued that the new system has improved both the security and efficiency of the grid authentication when compared with the traditional PKI-based and some current IBC-based models. 相似文献
22.
María Recamn Payo Niels Posthuma Angel Uruea de Castro Maarten Debucquoy Jef Poortmans 《Progress in Photovoltaics: Research and Applications》2014,22(7):711-725
The present research and development activities in crystalline silicon photovoltaics include the exploration of doping technologies alternative to the mainstream diffusion process. The goal is to identify those technologies with potential to increase the solar cell efficiency and reduce the cost per watt peak. In that respect, this work presents the selective epitaxial growth of silicon as a candidate for boron doping; showing the results of the evaluation of boron‐doped silicon epitaxial emitters on slurry and diamond‐coated wire‐sliced Czochralski material, their integration in interdigitated back contact solar cells, and the development of a novel process sequence to create the interdigitated rear junction of these devices using selective epitaxial growth. Boron‐doped silicon epitaxy is demonstrated to perform in the high efficiency range (>22%), and the use of selective epitaxial growth is proposed as a route for the simplification of the interdigitated back contact solar cell flow. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
23.
Nasim Rezaei Paul Procel Marcel Simor Zeger Vroon Miro Zeman Olindo Isabella 《Progress in Photovoltaics: Research and Applications》2020,28(9):899-908
An interdigitated back‐contacted (IBC) configuration is proposed for submicron copper indium gallium (di)selenide (CIGS). In a modelling platform, the structure was opto‐electrically optimized for maximum efficiency. The results are compared with a reference front/back‐contacted (FBC) solar cell with similar absorber thickness and exhibiting 11.9% efficiency. The electrical passivation at the front side is accomplished by an Al2O3 layer, which is endowed with negative fixed charges. The results indicate that with an optimal geometry and engineered bandgap grading, the efficiency of the new IBC structure can reach 17%. Additionally, with a reasonably low defect density in the absorber layer, efficiencies as high as 19.7% and open‐circuit voltage comparable with that of the record solar cell are possible with the IBC structure. 相似文献
24.
Paul Procel Haiyuan Xu Aurora Saez Carlos Ruiz‐Tobon Luana Mazzarella Yifeng Zhao Can Han Guangtao Yang Miro Zeman Olindo Isabella 《Progress in Photovoltaics: Research and Applications》2020,28(9):935-945
The contact resistivity is a key parameter to reach high conversion efficiency in solar cells, especially in architectures based on the so‐called carrier‐selective contacts. The importance of contact resistivity relies on the evaluation of the quality of charge collection from the absorber bulk through adjacent electrodes. The electrode usually consists of a stack of layers entailing complex charge transport processes. This is especially the case of silicon heterojunction (SHJ) contacts. Although it is known that in thin‐film silicon, the transport is based on subgap energy states, the mechanisms of charge collection in SHJ systems is not fully understood yet. Here, we analyse the physical mechanisms driving the exchange of charge among SHJ layers with the support of rigorous numerical simulations that reasonably replicate experimental results. We observe a connection between recombination and collection of carriers. Simulation results reveal that charge transport depends on the alignment and the nature of energy states at heterointerfaces. Our results demonstrate that transport based on direct energy transitions is more efficient than transport based on subgap energy states. Particularly, for positive charge collection, energy states associated to dangling bonds support the charge exchange more efficiently than tail states. The conditions for optimal carrier collection rely on the Fermi energy of the layers, in terms of activation energy of doped layers and carrier concentration of transparent conductive oxide. We observe that fill factor (FF) above 86% concurrently with 750‐mV open circuit voltage can be attained in SHJ solar cells with ρc lower than 45 mΩ·cm2 for p‐contact and 20 mΩ·cm2 for the n‐contact. Furthermore, for achieving optimal contact resistivity, we provide engineering guidelines that are valid for a wide range of silicon materials from amorphous to nanocrystalline layers. 相似文献
25.
Teng Choon Kho Kean Chern Fong Matthew Stocks Keith McIntosh Evan Franklin Sieu Pheng Phang Wensheng Liang Andrew Blakers 《Progress in Photovoltaics: Research and Applications》2020,28(10):1034-1044
This work presents results of a laboratory‐scale interdigitated back contact (IBC) solar cell with an independently measured efficiency of 25.0%, featuring open‐circuit voltage of 716 mV, short‐circuit current of 43.0 mA.cm−2 and fill factor of 81.0%. Notably, the high efficiency was achieved based on significant improvements resulting from the optimised cell structure, excellent SiO2‐SiNx‐SiOx (ONO) surface passivation, detailed bulk lifetime management strategy and improved random pyramid texturing. Experimental details and analysis of the individual improvements over prior work are presented in‐depth. 相似文献
26.
Michael Riencker Emily L. Warren Manuel Schnabel Henning Schulte‐Huxel Raphael Niepelt Rolf Brendel Pauls Stradins Adele C. Tamboli Robby Peibst 《Progress in Photovoltaics: Research and Applications》2019,27(5):410-423
Multi‐junction cells can significantly improve the energy yield of photovoltaic systems over a single‐junction cell. The internal interconnection scheme of the subcells is an important aspect in determining the resulting levelized cost of electricity. For a dual‐junction cell, two approaches are commonly discussed: series‐connected tandem cells with two terminals or independently working subcells in a four‐terminal (4T) tandem device. In this paper, we explore the working principle and the operation modes of a third, rarely discussed option: a three‐terminal (3T) tandem cell using a back‐contacted bottom cell with 3Ts. We use current–voltage measurements of illuminated 3T interdigitated back contact cells and confirm that the front and rear base contacts are at similar quasi‐Fermi level positions, which enables the bottom cell to either efficiently collect surplus carriers, in the case of a current‐limiting or carrier injecting top cell, or inject majority carriers, in the case of a current‐limiting bottom cell. As a result, no current matching is needed. The power output of an idealized 3T bottom cell without resistive effects is independent of the current density applied from the top cell. These characteristics of the 3T bottom cells enable a 3T tandem to operate as efficiently as a 4T tandem, while being compatible with monolithic design and not requiring intermediate grids. We propose a simple equivalent circuit model including additional resistive effects, which describes a real 3T bottom cell and achieves excellent agreement to the experiment. We deduce design guidelines for a 3T bottom cell in different operation regimes. 相似文献
27.
Milan Padilla Christian Reichel Nikolaus Hagedorn Andreas Fell Roman Keding Bernhard Michl Martin Kasemann Wilhelm Warta Martin C. Schubert 《Progress in Photovoltaics: Research and Applications》2016,24(3):326-339
Highest efficiency solar cells in industrial and R&D environments are increasingly sensitive to local performance limiting processing faults, which are best characterised by spatially resolved characterisation techniques. This work contains a discussion on the processing faults related to contact resistance and finger interruptions in interdigitated back contact silicon solar cells, which are prime example for a complex cell structure. Using experimental and simulated current–voltage measurements and luminescence images, we explore the strongly non‐linear effect of poor local contact resistances on the global series resistance, fill factor, short circuit current density and efficiency. A good agreement between global and spatially resolved characterisation of faults is found, and potential artefacts are discussed. In conclusion, we present seven cases of contacting faults in interdigitated back contact cells with distinct characteristics that can be identified using a flow chart of experiments. The resulting guideline should assist silicon solar cell manufacturers in localising and quantifying local contacting faults that reduce the cells efficiency in manufacturing of complex solar cells. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
28.
《Progress in Photovoltaics: Research and Applications》2017,25(12):989-995
Gapless interdigitated back contact (IBC) solar cells were fabricated with phosphorous back surface field on a boron emitter, using an ion implantation process. Boron emitter (boron ion implantation) is counter doped by the phosphorus back surface field (BSF) (phosphorus ion implantation) without gap. The gapless process step between the emitter and BSF was compared to existing IBC solar cell with gaps between emitters and BSFs obtained using diffusion processes. We optimized the doping process in the phosphorous BSF and boron emitter region, and the implied Voc and contact resistance relationship of the phosphorous and boron implantation dose in the counter doped region was analyzed. We confirmed the shunt resistance of the gapless IBC solar cells and the possibility of shunt behavior in gapless IBC solar cells. The highly doped counter doped BSF led to a controlled junction breakdown at high reverse bias voltages of around 7.5 V. After the doping region was optimized with the counter doped BSF and emitter, a large‐area (5 inch pseudo square) gapless IBC solar cell with a power conversion efficiency of 22.9% was made. 相似文献
29.
30.
物联网普遍存在遭受网络攻击类型多样化、没有安全保护标准、数据极易被截获或破解等安全风险,核心问题在于缺乏设备、服务提供者、应用、数据、交易等物的安全认证机制。因此,有必要建立一种提供认证鉴权和数据保护的方案体系,建立物与物、物与人之间的信任。密码技术是解决核心安全问题的基础理论和技术,而传统的证书体系并不适应于物联网环境,基于商密SM9的算法才是目前物联网安全认证的最佳选择。物联网安全平台依赖商密SM9算法的优势,有效克服了传统算法中密钥分发安全性弱等问题,深入物联网行业终端与应用层面,建立了面向物联网业务的端到端安全。 相似文献