1,721,108 research outputs found
Impact of Current Collecting Grids on the Scalability of 3-Terminal Perovskite/Silicon Tandems with Bipolar Transistor Architecture
Full text linkThe heterojunction bipolar transistor (HBT) structure is an attractive solution for developing three-terminal perovskite/silicon tandem solar cells compatible with dominant
silicon photovoltaic devices, such as PERC and heterojunction.
However, in contrast to three-terminal tandems based on interdigitated back contact silicon cells, the three-terminal HBT requires the implementation of the third contact at the base (middle) layer. To this aim, the simplest solution is to access the base layer from the cell front side by implementing a grid layout with top interdigitated contacts (TIC). In this work, we elaborate on the feasibility of the HBT structure for 3T perovskite/silicon tandem solar cells. We report, based on optical and drift-diffusion simulations, proof-of-concept designs with high efficiency potential, and we analyze, with the aid of circuit
level simulations, the implications of a TIC grid layout in the perspective of scaling up to large areas. Our results show that the HBT architecture is a promising candidate for developing 3T perovskite/silicon tandem solar cells compatible with industry
standard silicon photovoltaics
Physical simulation of perovskite/silicon three-terminal tandems based on bipolar transistor structure
Full text linkTandem solar cells made of organometal halide perovskite and crystalline silicon cells are one of the most
promising routes towards high eciency low cost photovoltaics. Among the possible architectures, monolithic
three-terminal tandems hold the promise of the highest energy/cost gure of merit, by combining the advantage
of two- and four-terminal approaches. Recently, three-terminal perovskite/silicon tandems have been reported,
based on interdigitated back contact heterojunction silicon cells. Alternative solutions that can be integrated
with double-sided contact silicon cells are worth to be investigated in view of their higher compatibility with
industrial mass production. In this work, we present a simulation-based proof-of-concept of PVK/Si threeterminal
tandem cells that use a heterostructure bipolar transistor structure. The extra terminal is implemented
at the common selective layer between the perovskite and silicon subcells, avoiding the use of any recombination
layer or tunneling junction. We demonstrate promising device performance through physics-based simulations
preliminarily validated against experimental data of other perovskite/silicon tandem technologies reported in
literature
Investigation on the Photovoltaic Performance of Quantum Dot Solar Cells through Self-Consistent Modeling of Transport and Photoelectron Processes
No full textThe use of quantum dots (QDs) in III-V solar cells is an attractive technology to enhance the power conversion efficiency of both single- and multi-junction solar cells. Recently, very interesting results have been demonstrated by combining the use of QD and modulation doping. However, a general consensus on the actual potentiality of the QD approach in terms of achievable efficiency improvement has not yet been reached, either due to the relative immaturity of the technology and because of several uncertainties about the detailed underlying physics, that involve a complex interplay between microscopic and nanoscopic physical processes. To tackle this problem, we have developed an ad hoc, multiscale oriented, modelling approach that couples a drift-diffusion transport model with a detailed description of QD carrier dynamics. In this contribution we present an investigation of the photovoltaic performance of representative GaAs-based QDSCs reported in literature, demonstrating a good accuracy in predicting typical QDSC photovoltaic characteristics. Based on such an approach, a deeper insight is provided on the impact of material and design parameters on the device performance
Cement-Based Radiative Coolers for Photovoltaics: Towards a Practical Design
No full textResearch conducted in the framework of MIRACLE Project (Photonic Metaconcrete with Infrared RAdiative Cooling capacity for Large Energy savings, GA 964450), coordinated by Dr. Jorge Sánchez Dolado, from Centro de Física de Materiales (CFM).In 2014, the experimental realization of radiative coolers capable of reaching sub-ambient temperatures
under direct sunlight has opened up new possibilities for the thermal management of solar cells. Radiative
coolers eject excess heat by emitting thermal radiation within the so-called atmosphere transparency
window. The completely passive nature of this process and its reliance on material properties only, make
radiative coolers extremely attractive in terms of energy efficiency. Integrated with a photovoltaic cell, the
radiative cooler can reduce the cell operating temperature, leading to high efficiency and lifetime gains.
Yet, most radiative coolers in the literature are metamaterials with scarce elements or complex fabrications
processes, or organic materials with potential UV instability, with questionable economic viability or
reliability. To address this problem, we have recently proposed cement-based materials as a low-cost,
scalable and stable solution for photovoltaics cooling, showing that their electromagnetic properties can be
tuned to maximize their thermal emissivity by acting on their microstructure. In particular, using a detailed
balance model, we have demonstrated that their cooling performance could increase the efficiency of silicon
solar cells by up to 9% and extended their lifetime by up to 4 times. In this work, we take a further step
towards the experimental realization of this attractive concept, by investigating possible approaches,
requirements and prospects for the practical design of photovoltaic systems employing cement-based
radiative coolers.This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 964450.-- Conference Proceedings of the 16th ICCC, Bangkok, 18-22 September 2023.Peer reviewe
Detailed-balance assessment of radiative cooling for multi-junction solar cells under unconcentrated and low-concentrated light
Full text linkMulti-junction solar cells are the best technology to achieve high-efficiency photovoltaics. Yet, their thermal management is crucial to ensure high performance and reliability, particularly in concentrating photovoltaic systems. Recent studies have proposed radiative cooling as an innovative, passive, cost-effective, and scalable technique to cool down solar cells. In this study, we analyze its impact on multi-junction solar cells under different illumination conditions by means of a detailed-balance model. First, we demonstrate that radiative cooling can provide greater efficiency gain in multi-junction devices than in single-junction ones despite the fact that the former heat up less than the latter. In fact, in multi-junction cells, the lower heating is more than compensated for by the stronger efficiency degradation with increasing temperature, due to their wider radiative recombination spectrum. Then, we explore two possible strategies to effectively use radiative cooling in low-concentration photovoltaic systems, such as building integrated concentrating photovoltaics. The first one is to combine the radiative cooler with a nonradiative cooling system, which then has relaxed performance requirements. The second one is to increase the radiative cooler area relative to that of the solar cell. Both approaches can provide significant performance benefits, whose magnitude depends on the selected design and application. For an optimal triple-junction cell under 10-sun concentration, we find that a radiative cooler having 5 the area of the solar cell reduces by 90% the nonradiative cooling power required to maintain the cell temperature at 60 C and achieves +2% absolute efficiency gain over 1-sun operation
Impact of Radiative Cooling on Multi-Junction Solar Cells Under Unconcentrated and Low-Concentrated Light
Full text linkMulti-junction solar cells are a key technology for high efficiency photovoltaics. Since their performance and reliability are strongly influenced by the operating temperature, their effective thermal management is an important concern, especially in concentrating photovoltaics. Radiative cooling is a cost-effective, passive, and scalable solution for thermal management of solar cells. This technique can effectively expel a large amount of heat by radiating it into outer space through the atmospheric transparency window between 8 and 13 μm, In this work, we analyze the impact of this cooling strategy on multi-junction solar cells under different illumination conditions by means of a detailed balance model for the cell/cooler system. We show that the increase in efficiency resulting from reduced operating temperature is more significant for multi-junction architectures in comparison to single-junction ones, because of their more negative temperature coefficient. Furthermore, we explore two viable approaches for successfully utilizing the radiative cooler in low-concentration photovoltaic systems. The first method involves increasing the size of the radiative cooler area, while the second entails combining it with a nonradiative cooling system
Detailed balance model of multi-junction solar cells with radiative cooling - dataset and code
No full textData, MATLAB software and plot scripts associated with the article "Detailed-balance assessment of radiative cooling for multi-junction solar cells under unconcentrated and low-concentrated light" (to appear in Solar Energy Materials and Solar Cells, 2024)
Dependence of quantum dot photocurrent on the carrier escape nature in InAs/GaAs quantum dot solar cells
No full textThis paper presents a theoretical study of the effect of the nature of the carrier escape from quantum dots (QDs) on the performance of InAs/GaAs QD solar cells (QDSCs), based on numerical simulations. Excitonic and non-excitonic dynamics of electrons and holes are considered in the modeling, by assuming identical or separate time constants for the intersubband carrier transfer processes in the ground and excited states. It is shown that the excitonic capture and escape allow us to explain the non-additive characteristic of the QD photocurrent, observed when the total photocurrent of the cell is much lower than the sum of the photocurrents contributed separately by the barrier and the nanostructures. This behavior is practically eliminated in the non-excitonic case. The correlated dynamics under the nonexcitonic scenario is analyzed by calculating the device sensitivity to small changes introduced in the escape time of electrons. It is stated that the non-variation of the QD photocurrent with this parameter could be interpreted as a consequence of either a correlated electron-hole escape from QDs, or a dominant recombination over the other involved processes. The ideality factor of the different QDSCs studied is also calculated from simulations under both concentrated sunlight and dark conditions. The obtained results are in line with experimental measurements published in the literature
Investigation on the Photovoltaic Performance of Quantum Dot Solar Cells through Self-Consistent Modeling of Transport and Quantum Dot Carrier Dynamics
Full text linkImpact of carrier dynamics on the photovoltaic performance of quantum dot solar cells
Full text linkThe study presents a theoretical investigation of the impact of individual electron and hole dynamics on the photovoltaic characteristics of InAs/GaAs quantum dot solar cells. The analysis is carried out by exploiting a model which includes a detailed description of quantum dots (QD) kinetics within a drift-diffusion formalism. Steady-state and transient simulations show that hole thermal spreading across the closely spaced QD valence band states allows to extract the maximum achievable photocurrent from the QDs; on the other hand, slow hole dynamics turns QDs into efficient traps, impairing the short circuit current despite the extended light harvesting provided by the QD
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