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Electron self-injection threshold for the tandem-pulse laser wakefield accelerator
摘要： A controllable injection scheme is key to producing high quality laser-driven electron beams and x rays. Self-injection is the most straightforward scheme leading to high current and peak energies but is susceptible to variations in laser parameters and target characteristics. In this work, improved control of electron self-injection in the nonlinear cavity regime using two laser-pulses propagating in tandem is investigated. In particular, the advantages of the tandem-pulse scheme in terms of injection threshold, electron energy, and beam properties in a regime relevant to betatron radiation are demonstrated. Moreover, it is shown that the laser power threshold for electron self-injection can be reduced by up to a factor of two compared to the standard, single-pulse wakefield scheme.
关键词： tandem-pulse,nonlinear cavity regime,laser wakefield accelerator,electron self-injection,betatron radiation
更新于2025-09-23 15:19:57
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Toward reliable high performing organic solar cells: Molecules, processing, and monitoring
摘要： A steady surge in device efficiencies of organic solar cells (OSCs) along with improvement in associated features, such as stability and facile processing methods, is expected to provide a realistic, feasible commercial option. The introduction of high performing donor and acceptor molecules along with tailored buffer layers has provided the impetus for the resurgence of this field. Further options of ternary and tandem architectures of these OSC systems should push this technology to competitive levels. A major hurdle, which is expected when these devices are evaluated for long-term performance in all weather conditions, is the level of degradation. We examine and address these stability-limiting factors in this perspective article. Modifications in microstructure/morphology and interfaces with time and energy levels defining the molecules form some of the critical intrinsic degradation pathways. Various strategies that have been used to limit the associated pathways of degradation of the active layer will be discussed. One such strategy is electric field-assisted thermal annealing treatment, which concomitantly also brings in a favorable vertical phase segregated active layer morphology. We also emphasize the utility of photocurrent noise measurements to monitor the level of degradation and possibly forecast the trajectory of long-term performance of OSCs.
关键词： processing methods,photocurrent noise measurements,electric field-assisted thermal annealing,device efficiencies,degradation,donor and acceptor molecules,organic solar cells,stability,ternary and tandem architectures
更新于2025-09-23 15:19:57
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Thin-Film Tandem Organic Solar Cells With Improved Efficiency
摘要： Seeking high power conversion efficiency is always a striving pathway for many researchers to commercialize organic solar cells (OSCs). Thus, it is essential to achieve high conversion efficiency to make solar oriented devices as truly green energy resource. In this paper, we report novel tandem structures based on organic materials in which homo and hybrid schemes are utilized. The homo tandem structures involve the well-known organic materials such as P3HT: PCBM and PTB7: PCBM as top and bottom absorber layers, while the hybrid tandem structure is made by the combination of P3HT: PCBM and PTB7: PCBM, respectively. Due to different absorption coefficients, simulation results indicate that the hybrid tandem structure exhibit large values for current density Jsc=22.60mA/cm2, open circuit voltage Voc= 0.85V, fill factor FF=68.21%, and efficiency ?=13.96%, compared to homo tandem cell and proves to be more efficient and highly stable towards high temperatures, which indicates that the proposed structure is more suitable for practical applications.
关键词： Organic solar cell,efficiency,homo,hybrid,tandem
更新于2025-09-23 15:19:57
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Mechanically Stacked, Two-Terminal Graphene-Based Perovskite/Silicon Tandem Solar Cell with Efficiency over 26%
摘要： A novel configuration for high-performant perovskite/silicon tandem solar cells is demonstrated using a facile mechanical stacking of the sub-cells. The resulting champion perovskite/silicon tandem solar cell exhibits a stabilized efficiency of 25.9% over an active area of 1.43 cm2.
关键词： graphene doping,stabilized efficiency,perovskite/silicon tandem solar cells,mechanical stacking
更新于2025-09-23 15:19:57
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Ligand engineering of colloid quantum dots and their application in all-inorganic tandem solar cells
摘要： How to effectively utilize the energy of the broad spectrum of sunlight is one of the basic problems in the research of tandem solar cells. Due to their size effect, quantum confinement effect and coupling effect, colloidal quantum dots (QDs) exhibit new physical properties that bulk materials don’t possess. CdX (X=Se, S, etc.) and PbX (X=Se, S, etc.) QDs prepared by hot-injection methods have been widely studied in the areas of photovolitaic devices. However, the surfactants surrounding QDs seriously hinder the charge transport of QDs based solar cells. Therefore, how to fabricate high-performance tandem solar cells via ligands engineering has become a major challenge. In this paper, the latest progress of colloidal QDs in the research of all-inorganic tandem solar cells was summarized. Firstly, the improvement of QDs surface ligands and the optimization of ligands engineering were discussed, and the control of the physical properties of QDs films were realized. From the aspects of colloidal QDs, ligand engineering, and solar cell preparation, the future development direction of colloidal QDs solar cells was proposed, providing technical guidances for the preparation of low-cost and high-efficiency nanocrystalline solar cells.
关键词： Tandem solar cell,Colloidal quantum dots,Hot-injection method,Ligand engineering
更新于2025-09-23 15:19:57
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A Taxonomy for Three-Terminal Tandem Solar Cells
摘要： Tandem and multijunction solar cells offer the only demonstrated path to terrestrial 1-sun solar cell efficiency over 30%. Three-terminal tandem (3TT) solar cells can overcome some of the limitations of tandem solar cell designs. However, the coupled nature of the cells adds a degree of complexity to the devices themselves and the ways that their performance can be measured and reported. While many different configurations of 3TT devices have been proposed, there is no standard taxonomy to discuss the device structure or loading topology. This Perspective proposes a taxonomy for 3TT solar cells to enable a common nomenclature for discussing these devices and their performance. It also provides a brief history of three-terminal devices in the literature and demonstrates that many different 3TT devices can work at efficiencies above 30% if properly designed.
关键词： efficiency,three-terminal tandem solar cells,nomenclature,design,taxonomy
更新于2025-09-23 15:19:57
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Atomic layer deposition of metal oxides for efficient perovskite single-junction and perovskite/silicon tandem solar cells
摘要： Aluminum-doped and undoped zinc oxide films were investigated as potential front and rear contacts of perovskite single and perovskite/silicon tandem solar cells. The films were prepared by atomic layer deposition (ALD) at low (<200 °C) substrate temperatures. The deposited films were crystalline with a single-phase wurtzite structure and exhibit excellent uniformity and low surface roughness which was confirmed by XRD and SEM measurements. Necessary material characterizations allow for realizing high-quality films with low resistivity and high optical transparency at the standard growth rate. Spectroscopic ellipsometry measurements were carried out to extract the complex refractive index of the deposited films, which were used to study the optics of perovskite single junction and perovskite/silicon tandem solar cells. The optics was investigated by three-dimensional finite-difference time-domain simulations. Guidelines are provided on how to realize perovskite solar cells exhibiting high short-circuit current densities. Furthermore, detailed guidelines are given for realizing perovskite/silicon tandem solar cells with short-circuit current densities exceeding 20 mA cm?2 and potential energy conversion efficiencies beyond 31%.
关键词： Zinc oxide,Tandem solar cells,Perovskite solar cells,Atomic layer deposition,Optical simulations
更新于2025-09-23 15:19:57
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Passivating contacts and tandem concepts: Approaches for the highest silicon-based solar cell efficiencies
摘要： The efficiency of photovoltaic energy conversion is a decisive factor for low-cost electricity from renewable energies. In recent years, the efficiency of crystalline silicon solar cells in mass production has increased annually by about 0.5–0.6%abs per year. In order to maintain this development speed, new technologies must be developed and transferred to industrial production. After the transition from full area Al back surface field cells to passivated emitter and rear contact cells, passivating contacts are an important step to get as close as possible to the efficiency limit of single junction Si solar cells. The theoretical background and the two prominent technologies for passivating contacts are presented and discussed. After implementing passivating contacts, the fundamental limit of single junction Si solar cells of 29.4% is in reach. Multi-junction solar cells are the most promising option to achieve efficiencies greater than 30%. Tandem technologies based on crystalline silicon as bottom cells have the advantage that they are based on a mature technology established on a gigawatt scale and can partially use the existing production capacity. In addition, silicon has an ideal bandgap for the lower subcell of a tandem solar cell. The two most promising material candidates for the top cell, i.e., III/V and perovskites, will be discussed. The presented technology routes show that silicon is able to maintain its outstanding position in photovoltaics in the coming years.
关键词： perovskites,multi-junction solar cells,III/V,photovoltaic energy conversion,passivating contacts,tandem technologies,crystalline silicon solar cells
更新于2025-09-23 15:19:57
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Combined Optical-Electrical Optimization of Cd1a??xZnxTe/Silicon Tandem Solar Cells
摘要： Although the fundamental limits have been established for the single junction solar cells, tandem configurations are one of the promising approaches to surpass these limits. One of the candidates for the top cell absorber is CdTe, as the CdTe photovoltaic technology has significant advantages: stability, high performance, and relatively inexpensive. In addition, it is possible to tune the CdTe bandgap by introducing, for example, Zn into the composition, forming Cd1?xZnxTe alloys, which can fulfill the Shockley–Queisser limit design criteria for tandem devices. The interdigitated back contact (IBC) silicon solar cells presented record high efficiencies recently, making them an attractive candidate for the rear cell. In this work, we present a combined optical and electrical optimization of Cd1?xZnxTe/IBC Si tandem configurations. Optical and electrical loss mechanisms are addressed, and individual layers are optimized. Alternative electron transport layers and transparent conductive electrodes are discussed for maximizing the top cell and tandem efficiency.
关键词： ZnTe,IBC silicon cell,c-Si,photovoltaic cell,CdTe,tandem cell,CdZnTe
更新于2025-09-23 15:19:57
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Heterostructure Improvements of the Solar Cells based on Perovskite
摘要： In this paper we present p-i-n GaAs & perovskite PV cells comparison of in-series or in-parallel connection. It is made based on the two tandems types with a non-monolithic connection and experimental sub-cells. The results based on tandems simulation are discussed. It is shown that the in-parallel connection is preferable than in-series even when the sub-cell photocurrents are not balanced and the open circuit voltages (Voc) are close to each other. In-parallel connection cell efficiency more than 22 % is demonstrated for the GaAs shading effect by MAPbI3 film, with an achieved short-circuit current density (Jsc) - 39 mA/cm2.
关键词： perovskite,solar cell,tandem
更新于2025-09-23 15:19:57