Reliability of charge carrier recombination data determined with charge extraction methods

Kniepert, Juliane; Paulke, Andreas; Perdigón‐Toro, Lorena; Kurpiers, Jona; Zhang, Huotian; Gao, Feng; Yuan, Jun; Zou, Yingping; Corre, Vincent M. Le; Koster, L. Jan Anton; Neher, Dieter

doi:10.1063/1.5129037

Cited by 17 publications

(13 citation statements)

References 48 publications

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“…TDCF has been already applied to PM6:Y6 and gave excellent agreement to BACE results. [ 54 ] The corresponding TDCF transients for PM6:N4 are shown in Figure S5 (Supporting Information). Analysis of these transients with an established model yielded the same k 2 as obtained via BACE and PIA, as marked in Figure 1d.…”

Section: Resultsmentioning

confidence: 99%

Understanding the Role of Order in Y‐Series Non‐Fullerene Solar Cells to Realize High Open‐Circuit Voltages

Perdigón‐Toro

Phuong

Eller

et al. 2022

Advanced Energy Materials

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Section: Resultsmentioning

confidence: 99%

Understanding the Role of Order in Y‐Series Non‐Fullerene Solar Cells to Realize High Open‐Circuit Voltages

Perdigón‐Toro

Phuong

Eller

et al. 2022

Advanced Energy Materials

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“…Except for some tailing at low fluences and early times, we observe that all R ( n coll , t del ) data fall onto one line, independent of the initial fluence, and this line has a slope of two in the log‐log plot. This proves that R does not explicitly depend on t del and that nondispersive bimolecular recombination of free charges in the bulk of the blend is the predominant mechanism in this blend . The situation is clearly different from donor–acceptor blends with large energetic disorder, such as TQ1:PCBM, where recombination was found to be dispersive up to the microsecond time range .…”

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confidence: 84%

Barrierless Free Charge Generation in the High‐Performance PM6:Y6 Bulk Heterojunction Non‐Fullerene Solar Cell

et al. 2020

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Organic solar cells are currently experiencing a second golden age thanks to the development of novel non‐fullerene acceptors (NFAs). Surprisingly, some of these blends exhibit high efficiencies despite a low energy offset at the heterojunction. Herein, free charge generation in the high‐performance blend of the donor polymer PM6 with the NFA Y6 is thoroughly investigated as a function of internal field, temperature and excitation energy. Results show that photocurrent generation is essentially barrierless with near‐unity efficiency, regardless of excitation energy. Efficient charge separation is maintained over a wide temperature range, down to 100 K, despite the small driving force for charge generation. Studies on a blend with a low concentration of the NFA, measurements of the energetic disorder, and theoretical modeling suggest that CT state dissociation is assisted by the electrostatic interfacial field which for Y6 is large enough to compensate the Coulomb dissociation barrier.

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“…Unfortunately, only few studies concerned the interplay between free carrier generation and motion in NFA-based blends, [51][52][53] and even fewer included the measurement of energetic disorder [47,50,54]. These studies yielded a fairly wide spread of mobilities and recombination coefficients even for the same material combination, which may in part be related to the details of the molecular structure (e.g.…”

Section: Energetic Disorder (Mev)mentioning

confidence: 99%

General Rules for the Impact of Energetic Disorder and Mobility on Nongeminate Recombination in Phase-Separated Organic Solar Cells

et al. 2021

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State of the art organic solar cells exhibit power conversion efficiencies of 18 % and above.These devices benefit from a significant suppression of free charge recombination with regard to the Langevin-limit of charge encounter in a homogeneous medium. It has been recognized that the main cause of suppressed free charge recombination is the reformation and 2 resplitting of charge transfer states at the interface between donor and acceptor domains.Here, we use kinetic Monte Carlo simulations to understand the interplay between free charge motion and recombination in an energetically-disordered phase-separated donoracceptor blend. We identify conditions under which recombination is encounter-dominated and resplitting-dominated. In the latter regime, the non-geminate recombination coefficient becomes independent of the attempt-to-hop frequency, and for a given disorder, independent of charge carrier mobility. Our simulations show that free charge encounter in the phase-separated disordered blend is determined by the average mobility of all carriers, while CT reformation and resplitting involves mostly states near the transport energy. As a consequence, charge encounter is more affected by increased disorder than the resplitting of the CT state. As a consequence, the larger is the energetic disorder, the stronger will 𝐶𝑇resplitting suppress non-geminate recombination versus the Langevin-limit. These findings have important implications for the understanding of suppressed recombination in solar cells with non-fullerene acceptors which are known to exhibit lower energetic disorder than fullerenes.

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Reliability of charge carrier recombination data determined with charge extraction methods

Abstract: (2019). Reliability of charge carrier recombination data determined with charge extraction methods.

Cited by 17 publications

References 48 publications

Understanding the Role of Order in Y‐Series Non‐Fullerene Solar Cells to Realize High Open‐Circuit Voltages

Understanding the Role of Order in Y‐Series Non‐Fullerene Solar Cells to Realize High Open‐Circuit Voltages

Barrierless Free Charge Generation in the High‐Performance PM6:Y6 Bulk Heterojunction Non‐Fullerene Solar Cell

General Rules for the Impact of Energetic Disorder and Mobility on Nongeminate Recombination in Phase-Separated Organic Solar Cells

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