Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet excitons; in the benchmark PM6:Y6 blend 5, this fraction reaches 90%, reducing the open-circuit voltage by 60 mV.
In organic solar cells, the recombination of free charges proceeds via the formation of charge-transfer excitons, with an electron on the acceptor material and a hole on the donor material.
In both cases the incident photon energy is lost and fewer carriers are collected at the electrodes. Hence, charge carrier recombination is one of the key loss mechanisms in organic solar cells. In this review the latest on geminate and nongeminate recombination is discussed. 1. Introduction
In particular, bimolecular recombination rates have only been sparsely investigated in these solar cells 18, 20, 21, 22, 23. It is known that non-geminate recombination plays in an important role in the fill factor of solar cells 24, as well as the open-circuit voltage 25, and therefore the power-conversion efficiency.
The reduced recombination is essential for the high fill factors of these solar cells. The Langevin reduction factors are observed to correlate with the quadrupole moment of the acceptors, which is responsible for band bending at the donor–acceptor interface, forming a barrier for charge recombination.
Recombination in organic solar cells has been found to possess similar dependencies . Thus it is clear that higher reaction orders at least in part originate from spatial gradients of the carrier density and the carrier density dependence of the mobility.
Insights into charge dynamics and recombination processes in …
The generation of photocurrent in the organic solar cell can be overall described by the following processes: (i) light absorption and exciton formation, (ii) exciton migration or …
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Decoding Charge Recombination through Charge …
We show for the first time how field‐dependent charge generation, obtained from time‐delayed collection field (TDCF), and the bimolecular recombination coefficient, obtained from bias‐assisted charge …
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Selenium substitution for dielectric constant improvement and …
Dielectric constant of non-fullerene acceptors plays a critical role in organic solar cells in terms of exciton dissociation and charge recombination. Current acceptors feature a dielectric ...
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Insights into charge dynamics and recombination processes in …
Charge transport and recombination in bulk heterojunction solar cells studied by the photoinduced charge extraction in linearly increasing voltage technique Appl Phys Lett, 86 ( 2005 ), Article 112104, 10.1063/1.1882753
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Charge Transport and Recombination in Organic Solar Cells …
where (frac{e{{a}^{2}}}{hbar }) has the dimension of a carrier mobility, and is close to 1 cm 2 /Vs for most organic crystals.. It is also worth noting that at high field (> 10 5 V/cm), the carrier transport in organic materials is field-dependent. This is because the external field can alter the columbic potentials near localized-energy levels, thus increasing the electron …
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Competition between recombination and extraction of free …
Among the parameters that characterize a solar cell and define its power-conversion efficiency, the fill factor is the least well understood, making targeted improvements difficult. Here we ...
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Reduced bimolecular charge recombination in efficient organic …
Here, we investigate the bimolecular recombination rate and charge transport in a series of high-performance organic solar cells based on non-fullerene acceptors. From …
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Enhanced understanding of recombination mechanisms in high …
6 · In alignment with Equations 2 and 3, it revealed that trap-assisted recombination predominates at charge carrier densities below 1 × 10 14 cm −3, and above that, radiative recombination starts to play role, characterized by a radiative …
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Charge Carrier Generation, Recombination, and Extraction in …
The low open-circuit voltage is a significant drawback of organic solar cells; improving V OC would definitely boost the commercialization of organic solar cells . 1.2 Charge-Transfer States and Geminate Charge Recombination. In this section we discuss in more detail the role of CT states. At the D–A interface, only a fraction of electrons ...
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Reduced bimolecular charge recombination in efficient organic solar …
Here, we investigate the bimolecular recombination rate and charge transport in a series of high-performance organic solar cells based on non-fullerene acceptors. From steady-state dark...
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Comprehensive Study of Carrier Recombination in …
This study aims to deepen the understanding of charge carrier recombination in CdTe solar cells and to explore alternative dynamical characterization methods that address the limitations found in conventionally used time-resolved photoluminescence for CdTe solar cells. Transient photovoltage and transient photocurrent techniques are utilized to ...
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The role of charge recombination to triplet excitons in organic …
Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non …
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Selenium substitution for dielectric constant improvement and …
Dielectric constant of non-fullerene acceptors plays a critical role in organic solar cells in terms of exciton dissociation and charge recombination. Current acceptors feature a …
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Charge Photogeneration and Recombination Dynamics in PTQ10:Y6 Solar Cells
In this work, charge photogeneration dynamics in PTQ10:Y6 solar cells were studied by steady-state and time-resolved spectroscopies. For neat donor and acceptor films, we determined the exciton diffusion coefficients of PTQ10 and Y6 as 1.3 × 10−3 cm2·s−1 and 6.8 × 10−3 cm2·s−1, respectively. Furthermore, we find the LUMO and HOMO level offsets of 0.14 …
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Triplet sensitization via charge recombination at organic ...
The role of charge recombination to triplet excitons in organic solar cells. Nature 597, 666–671 (2021). Article CAS Google Scholar
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The role of charge recombination to triplet excitons in organic …
Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet excitons; …
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Charge carrier recombination in organic solar cells
In the charge extraction technique, a solar cell is held at fixed bias and illumination condition then the light is quickly turned off while the device is simultaneously …
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Modulating Acceptor Phase Leads to 19.59% Efficiency Organic Solar Cells
2 · Optimized acceptor morphology promoted exciton diffusion and segregation, reduced charge extraction time, improved carrier lifetime, accelerated charge transport, and suppressed charge recombination, thereby enhancing the photovoltaic performance of OSCs with PM6:Y6, PM6:L8-BO, PM6:BTP-eC9, and PM6:N3. Specifically, devices composed of PM6:Y6 …
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Modulating Acceptor Phase Leads to 19.59% Efficiency Organic …
2 · Optimized acceptor morphology promoted exciton diffusion and segregation, reduced charge extraction time, improved carrier lifetime, accelerated charge transport, and …
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The role of charge recombination to triplet excitons in organic solar cells
Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet...
Learn More
Decoding Charge Recombination through Charge Generation in …
We show for the first time how field‐dependent charge generation, obtained from time‐delayed collection field (TDCF), and the bimolecular recombination coefficient, obtained from bias‐assisted charge extraction (BACE) at operating charge carrier densities, and mobilities (using space charge limited current [SCLC], resistance ...
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Suppressing Nongeminate Charge Recombination Triggers …
1 · Bilayer organic solar cells, composed of a donor and acceptor layer, provide independent optimization of each layer to enhance the photovoltaic performance. However, the power conversion efficiency remains lower than that of bulk heterojunction cells. Herein, we focus on suppressing nongeminate charge recombination by tuning the acceptor layer''s morphology …
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Charge carrier recombination in organic solar cells
In the charge extraction technique, a solar cell is held at fixed bias and illumination condition then the light is quickly turned off while the device is simultaneously short circuited. The resulting photocurrent transient can then be integrated to determine the average charge carrier density present in the device at the initial ...
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The role of charge recombination to triplet excitons in organic solar cells
Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet excitons; in the benchmark PM6:Y6 blend 5, this fraction reaches 90%, reducing the …
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Modeling of Charge Injection, Recombination, and Diffusion in …
A model of charge population decay upon ultrafast optical pulse excitation in complete, working perovskite solar cells is proposed. The equation, including charge injections (extractions) from perovskite to contact materials, charge diffusion, and charge recombination via first-, second-, and third-order processes, is solved using numerical simulations.
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Highly efficient organic solar cells enabled by suppressing triplet ...
The role of charge recombination to triplet excitons in organic solar cells. Nature 597, 666–671 (2021). Article ADS PubMed CAS Google Scholar
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Probing charge carrier dynamics in metal halide perovskite solar cells ...
For charge recombination, the common method is to correspond the lower frequency domain characteristics of IS to the charge recombination process. This was used to verify the positive effects of various optimization methods on reducing charge recombination in PSCs. These approaches include device structure optimization, 123 post-processing, 124 charge extraction …
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Suppressing Nongeminate Charge Recombination Triggers 19.5
1 · Bilayer organic solar cells, composed of a donor and acceptor layer, provide independent optimization of each layer to enhance the photovoltaic performance. However, the power …
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Insights into charge dynamics and recombination processes in …
The generation of photocurrent in the organic solar cell can be overall described by the following processes: (i) light absorption and exciton formation, (ii) exciton migration or diffusion to the donor-acceptor interface within its lifetime, (iii) charge separation into free electron and hole and (iv) charge migration to the electrodes. Other ...
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