Showing papers on "Photovoltaic system published in 2021"

Efficient perovskite solar cells via improved carrier management

Abstract: Metal halide perovskite solar cells (PSCs) are an emerging photovoltaic technology with the potential to disrupt the mature silicon solar cell market. Great improvements in device performance over the past few years, thanks to the development of fabrication protocols1-3, chemical compositions4,5 and phase stabilization methods6-10, have made PSCs one of the most efficient and low-cost solution-processable photovoltaic technologies. However, the light-harvesting performance of these devices is still limited by excessive charge carrier recombination. Despite much effort, the performance of the best-performing PSCs is capped by relatively low fill factors and high open-circuit voltage deficits (the radiative open-circuit voltage limit minus the high open-circuit voltage)11. Improvements in charge carrier management, which is closely tied to the fill factor and the open-circuit voltage, thus provide a path towards increasing the device performance of PSCs, and reaching their theoretical efficiency limit12. Here we report a holistic approach to improving the performance of PSCs through enhanced charge carrier management. First, we develop an electron transport layer with an ideal film coverage, thickness and composition by tuning the chemical bath deposition of tin dioxide (SnO2). Second, we decouple the passivation strategy between the bulk and the interface, leading to improved properties, while minimizing the bandgap penalty. In forward bias, our devices exhibit an electroluminescence external quantum efficiency of up to 17.2 per cent and an electroluminescence energy conversion efficiency of up to 21.6 per cent. As solar cells, they achieve a certified power conversion efficiency of 25.2 per cent, corresponding to 80.5 per cent of the thermodynamic limit of its bandgap.

Wind and Solar Power Systems: Design, Analysis, and Operation

Abstract: This book provides technological and socio-economic coverage of renewable energy. It discusses wind power technologies, solar photovoltaic technologies, large-scale energy storage technologies, and ancillary power systems. In this new edition, the book addresses advancements that have been made in renewable energy: grid-connected power plants, power electronics converters, and multi-phase conversion systems. The text has been revised to include up-to-date material, statistics, and current technology trends. Three new chapters have been added to cover turbine generators, AC and DC wind systems, and recent advances solar power conversion. Discusses additional renewable energy sources, such as ocean, special turbines, etc. Covers system integration for solar and wind energy Presents emerging DC wind systems Includes coverage on turbine generators Updated sections on solar power conversion It offers students, practicing engineers, and researchers a comprehensive look at wind and solar power technologies. It is designed as a reference and can serve as a textbook for senior undergraduates in a one-semester course on renewable power or energy systems.

Organic Solar Cells with 18% Efficiency Enabled by an Alloy Acceptor: A Two-in-One Strategy

Abstract: The trade-off between the open-circuit voltage (Voc ) and short-circuit current density (Jsc ) has become the core of current organic photovoltaic research, and realizing the minimum energy offsets that can guarantee effective charge generation is strongly desired for high-performance systems. Herein, a high-performance ternary solar cell with a power conversion efficiency of over 18% using a large-bandgap polymer donor, PM6, and a small-bandgap alloy acceptor containing two structurally similar nonfullerene acceptors (Y6 and AQx-3) is reported. This system can take full advantage of solar irradiation and forms a favorable morphology. By varying the ratio of the two acceptors, delicate regulation of the energy levels of the alloy acceptor is achieved, thereby affecting the charge dynamics in the devices. The optimal ternary device exhibits more efficient hole transfer and exciton separation than the PM6:AQx-3-based system and reduced energy loss compared with the PM6:Y6-based system, contributing to better performance. Such a "two-in-one" alloy strategy, which synergizes two highly compatible acceptors, provides a promising path for boosting the photovoltaic performance of devices.

Fused-Ring Electron Acceptors for Photovoltaics and Beyond.

Abstract: ConspectusEmerging solar cells that convert clean and renewable solar energy to electricity, such as organic solar cells (OSCs) and perovskite solar cells (PSCs), have attracted increasing attention owing to some merits such as facile fabrication, low cost, flexibility, and short energy payback time. The power conversion efficiencies (PCEs) of OSCs and PSCs have exceeded 18% and 25%, respectively.Fullerene derivatives have high electron affinity and mobility with an isotropic transport feature. Fullerene-based OSCs yielded superior PCEs to other acceptors and have dominated electron acceptor materials from 1995 to 2015. However, some drawbacks of fullerenes, such as weak visible absorption, limited tunability of electronic properties, laborious purification, and morphological instability, restrict further development of OSCs toward higher PCEs and practical applications. The theoretical PCE of fullerene-based OSCs is limited to ∼13% due to the relatively large energy losses. Many efforts have been dedicated to developing new acceptor systems beyond fullerenes, and some successful systems such as rylene diimides have achieved PCEs up to ca. 11%.In 2015, our group pioneered a new class of electron acceptors, fused-ring electron acceptor (FREA), as represented by the star molecule ITIC. The chemical features of FREAs include: (1) a modular structure, consisting of an electron-donating core, electron-withdrawing end groups, π-bridges, and side chains, which benefits molecular tailoring; (2) facile synthesis, purification, and scalability. The physical features of FREAs include: (1) a broad modulation range of absorption and energy levels; (2) strong absorption, especially in the 700-1000 nm region; (3) high electron mobility. The device features of FREAs include: (1) low voltage loss; (2) high efficiency; (3) good stability. The FREAs boosted PCEs of the OSCs up to 18% and initiated the transformation from the fullerene to nonfullerene era of this field. FREAs can also be used in PSCs as interfacial layers, electron transport layers, or active layers, improving both efficiency and stability of the devices. Beyond photovoltaic applications, FREAs can also be used in photodetectors, field-effect transistors, two-photon absorption, photothermal therapy, solar water splitting, etc.In this Account, we review the development of the FREAs and their applications in OSCs, PSCs, and other related fields. Molecular design, device engineering, photophysics, and applications of FREAs are discussed in detail. Future research directions toward performance optimization and commercialization of FREAs are also proposed.

Flexible and efficient perovskite quantum dot solar cells via hybrid interfacial architecture.

Abstract: All-inorganic CsPbI3 perovskite quantum dots have received substantial research interest for photovoltaic applications because of higher efficiency compared to solar cells using other quantum dots materials and the various exciting properties that perovskites have to offer These quantum dot devices also exhibit good mechanical stability amongst various thin-film photovoltaic technologies We demonstrate higher mechanical endurance of quantum dot films compared to bulk thin film and highlight the importance of further research on high-performance and flexible optoelectronic devices using nanoscale grains as an advantage Specifically, we develop a hybrid interfacial architecture consisting of CsPbI3 quantum dot/PCBM heterojunction, enabling an energy cascade for efficient charge transfer and mechanical adhesion The champion CsPbI3 quantum dot solar cell has an efficiency of 151% (stabilized power output of 1461%), which is among the highest report to date Building on this strategy, we further demonstrate a highest efficiency of 123% in flexible quantum dot photovoltaics

A unified description of non-radiative voltage losses in organic solar cells

Abstract: Recent advances in organic solar cells based on non-fullerene acceptors (NFAs) come with reduced non-radiative voltage losses (ΔVnr). Here we show that, in contrast to the energy-gap-law dependence observed in conventional donor:fullerene blends, the ΔVnr values in state-of-the-art donor:NFA organic solar cells show no correlation with the energies of charge-transfer electronic states at donor:acceptor interfaces. By combining temperature-dependent electroluminescence experiments and dynamic vibronic simulations, we provide a unified description of ΔVnr for both fullerene- and NFA-based devices. We highlight the critical role that the thermal population of local exciton states plays in low-ΔVnr systems. An important finding is that the photoluminescence yield of the pristine materials defines the lower limit of ΔVnr. We also demonstrate that the reduction in ΔVnr (for example, <0.2 V) can be obtained without sacrificing charge generation efficiency. Our work suggests designing donor and acceptor materials with high luminescence efficiency and complementary optical absorption bands extending into the near-infrared region. Organic solar cells based on non-fullerene acceptors have enabled high efficiencies yet their charge dynamics and its impact on the photovoltaic parameters are not fully understood. Now, Chen et al. provide a general description of non-radiative voltage losses in both fullerene and non-fullerene solar cells.

Advanced research trends in dye-sensitized solar cells

Abstract: Dye-sensitized solar cells (DSSCs) are an efficient photovoltaic technology for powering electronic applications such as wireless sensors with indoor light. Their low cost and abundant materials, as well as their capability to be manufactured as thin and light-weight flexible solar modules highlight their potential for economic indoor photovoltaics. However, their fabrication methods must be scaled to industrial manufacturing with high photovoltaic efficiency and performance stability under typical indoor conditions. This paper reviews the recent progress in DSSC research towards this goal through the development of new device structures, alternative redox shuttles, solid-state hole conductors, TiO2 photoelectrodes, catalyst materials, and sealing techniques. We discuss how each functional component of a DSSC has been improved with these new materials and fabrication techniques. In addition, we propose a scalable cell fabrication process that integrates these developments to a new monolithic cell design based on several features including inkjet and screen printing of the dye, a solid state hole conductor, PEDOT contact, compact TiO2, mesoporous TiO2, carbon nanotubes counter electrode, epoxy encapsulation layers and silver conductors. Finally, we discuss the need to design new stability testing protocols to assess the probable deployment of DSSCs in portable electronics and internet-of-things devices.

Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

Abstract: Perovskite solar cells (PSCs) have become a promising photovoltaic (PV) technology, where the evolution of the electron-selective layers (ESLs), an integral part of any PV device, has played a distinctive role to their progress. To date, the mesoporous titanium dioxide (TiO2 )/compact TiO2 stack has been among the most used ESLs in state-of-the-art PSCs. However, this material requires high-temperature sintering and may induce hysteresis under operational conditions, raising concerns about its use toward commercialization. Recently, tin oxide (SnO2 ) has emerged as an attractive alternative ESL, thanks to its wide bandgap, high optical transmission, high carrier mobility, suitable band alignment with perovskites, and decent chemical stability. Additionally, its low-temperature processability enables compatibility with temperature-sensitive substrates, and thus flexible devices and tandem solar cells. Here, the notable developments of SnO2 as a perovskite-relevant ESL are reviewed with emphasis placed on the various fabrication methods and interfacial passivation routes toward champion solar cells with high stability. Further, a techno-economic analysis of SnO2 materials for large-scale deployment, together with a processing-toxicology assessment, is presented. Finally, a perspective on how SnO2 materials can be instrumental in successful large-scale module and perovskite-based tandem solar cell manufacturing is provided.

Perovskite Solar Cells for Space Applications: Progress and Challenges.

Abstract: Metal halide perovskites have aroused burgeoning interest in the field of photovoltaics owing to their versatile optoelectronic properties. The outstanding power conversion efficiency, high specific power (i.e., power to weight ratio), compatibility with flexible substrates, and excellent radiation resistance of perovskite solar cells (PSCs) enable them to be a promising candidate for next-generation space photovoltaic technology. Nevertheless, compared with other practical space photovoltaics, such as silicon and III-V multi-junction compound solar cells, the research on PSCs for space applications is just in the infancy stage. Therefore, there are considerable interests in further strengthening relevant research from the perspective of both mechanism and technology. Consequently, the approaches used for and the consequences of PSCs for space applications are reviewed. This review provides an overview of recent progress in PSCs for space applications in terms of performance evolution and mechanism exploration of perovskite films and devices under space extreme environments.

Thermal expansion optimization in solar aircraft using tangent hyperbolic hybrid nanofluid: a solar thermal application

Abstract: Solar energy is the leading thermal source from the sun, with huge use of technology such as photovoltaic cells, solar power plates, photovoltaic lighting, and solar pumping water. The current effort deals with solar energy analysis and a technique to enhance solar aircraft effectiveness by using solar and nanotechnological energy. The work is based on the investigation of thermal transfer by utilizing hybrid nanofluid past an inside solar wings parabolic trough solar collector (PTSC) to rich the studies of the solar aircraft wings. The thermal source is titled solar radiative flow. For various properties such as porous media, Cattaneo Christov heat flux, viscous dissipation, play heating and thermal energy flow, the heat transfer efficiency of the wings is verified. In the case of the tangent hyperbolic fluid, the entropy generation analysis was applied. The modeled energy and momentum equations were managed using the well-established numerical plan known as the Keller box process. This paper is made up of double-different kinds of nano solid particles, Cu (copper) and ZrO2 (zirconium dioxide) in EG (ethylene glycol) as standard fluid. Various control parameters are discussed and shown in figures and tables for velocity, shear stress, temperature outlines, frictional factor, and Nusselt number. The efficiency in the aircraft wings in the case of thermal radiation amplification and variable thermal conduction parameters is seen to be improved in terms of thermal transfer. In comparison to the traditional nanofluid, hybrid nanofluid is the ideal source of heat transfer. The thermal efficiency of ZrO2–Cu/EG compared to Cu-EG decreases to a low of 2.6% and peaks to 3.6%.

Multi-objective optimization and multi-criteria decision-making methods for optimal design of standalone photovoltaic system: A comprehensive review

Abstract: Standalone photovoltaic (SAPV) systems have been considered as promising and fast development renewable energy sources due to free-noise, easy availability, and low-cost, especially for remote areas. However, the main disadvantages of these systems are low energy conversion and high capital cost. Therefore, many factors should be considered before installing the SAPV systems such as types of PV panels and configurations, mathematical models of PV module, storage battery, environmental criteria, sizing method based on techno-economic objectives, and selection the final optimum configuration. The goals of this paper are to presents a comprehensive review of the recent development in designing SAPV systems based on multi-objective optimization (MOO) and multi-criteria decision-making (MCDM) methodologies, including the mathematical models used in estimating the output power of the PV module and storage battery are also presented. Finally, the techno-economic criteria for assessing the performance of the SAPV system are considered. This will help the designers and customers to choose the most suitable design before installing the SAPV system. For supplementary resources and further discussions, please refer to the devoted homepage at http://aliasgharheidari.com .

Slot-die coating large-area formamidinium-cesium perovskite film for efficient and stable parallel solar module.

Abstract: Perovskite solar cells have emerged as one of the most promising thin-film photovoltaic (PV) technologies and have made a strong debut in the PV field. However, they still face difficulties with up-scaling to module-level devices and long-term stability issue. Here, we report the use of a room-temperature nonvolatile Lewis base additive, diphenyl sulfoxide(DPSO), in formamidinium-cesium (FACs) perovskite precursor solution to enhance the nucleation barrier and stabilize the wet precursor film for the scalable fabrication of uniform, large-area FACs perovskite films. With a parallel-interconnected module design, the resultant solar module realized a certified quasi-stabilized efficiency of 16.63% with an active area of 20.77 cm2 The encapsulated modules maintained 97 and 95% of their initial efficiencies after 10,000 and 1187 hours under day/night cycling and 1-sun equivalent white-light light-emitting diode array illumination with maximum power point tracking at 50°C, respectively.

22.8%-Efficient single-crystal mixed-cation inverted perovskite solar cells with a near-optimal bandgap

Abstract: Expanding the near-infrared (NIR) response of perovskite materials to approach the ideal bandgap range (1.1–1.4 eV) for single-junction solar cells is an attractive step to unleash the full potential of perovskite solar cells (PSCs). However, polycrystalline formamidinium lead triiodide (FAPbI3)-based absorbers, used in record-efficiency PSCs, currently offer the smallest bandgap that can be achieved for lead-halide perovskite thin films (>100 meV larger than the optimal bandgap). Here, we uncover that utilizing a mixed-cation single-crystal absorber layer (FA0.6MA0.4PbI3) is capable of redshifting the external quantum efficiency (EQE) band edge past that of FAPbI3 polycrystalline solar cells by about 50 meV – only 60 meV larger than that of the top-performing photovoltaic material, GaAs – leading to EQE-verified short-circuit current densities exceeding 26 mA cm−2 without sacrificing the open-circuit voltage (VOC), and therefore, yielding power conversion efficiencies of up to 22.8%. These figures of merit not only set a new record for SC-PSCs and are among the highest reported for inverted-structured-PSCs, but also offer an avenue for lead halide PSCs to advance their performance toward their theoretical Shockley–Queisser Limit potential.

Prospects for metal halide perovskite-based tandem solar cells

Abstract: Over the past decade, metal halide perovskite photovoltaics have been a major focus of research, with single-junction perovskite solar cells evolving from an initial power conversion efficiency of 3.8% to reach 25.5%. The broad bandgap tunability of perovskites makes them versatile candidates as the subcell in a tandem photovoltaics architecture. Stacking photovoltaic absorbers with cascaded bandgaps in a multi-junction device can potentially overcome the Shockley–Queisser efficiency limit of 33.7% for single-junction solar cells. There is now intense activity in developing tandem solar cells that pair perovskite with either itself or with a variety of mature photovoltaic technologies such as silicon and Cu(In,Ga)(S,Se)2 (CIGS). In this review, we survey recent advances in the field and discuss its outlook. A discussion of the evolution, present status and future outlook for tandem solar cells employing perovskite materials.

Residential net-zero energy buildings: Review and perspective

Abstract: Advancements in residential net-zero energy buildings (NZEBs) could significantly reduce energy consumption and greenhouse gas emissions. NZEB design considerations broadly categorize into energy infrastructure connections, renewable energy sources, and energy-efficiency measures. There is a lack of systematic literature review focused on recent progress in residential NZEBs. Therefore, this work provides an overview of each category including recent developments (last ≈ 10 years), aiming to provide references and support of wider and more successful implementation of residential NZEBs throughout the globe. The discussed energy infrastructure connections include electrical grids, district heating/cooling networks, and energy storage options including vehicle-to-home and hydrogen storage. Renewable energy sources considered here are solar photovoltaic and solar thermal, wind, and biomass including micro combined heat and power (CHP) systems. The final category detailed is energy-efficiency measures, which include improved building envelope designs, efficient HVAC systems, efficient domestic hot water systems, and phase change material integration. Within these categories there are many technology options, which makes selecting the ‘best’ configuration more difficult but allows design flexibility to adapt to local climates and other considerations (i.e. building codes, energy resources, costs). This paper provides references and highlights technology options to achieve residential NZEBs throughout the world.