Mitigating Exciton Recombination Losses in Organic Solar Cells by Engineering Nonfullerene Molecular Crystallization Behavior

Advanced Energy Materials, Год журнала: 2023, Номер 13(38)

Опубликована: Авг. 27, 2023

Abstract Although the advances in organic solar cells (OSCs) have been considerable, their efficiency is still limited by recombination losses. Photogenerated electrons and holes are generally bound as localized excitons semiconductors. The transition from into free charges requires diffusion dissociation processes, which parasitic losses exist. Reducing these necessary for highly efficient OSCs. crystallization behavior of active layers can influence exciton dissociation. In this work, different additives delicately designed to control behavior. It found that quality be improved controlling aggregation nonfullerene acceptors. π–π stacking blend films becomes compact, meanwhile, vertical direction more uniform. These beneficial excitons. As a consequence, reduced power convention efficiencies (PCEs) significantly. Meanwhile, general applicability additive demonstrated various photovoltaic systems, PCE 19.3% achieved D18:BTP‐eC9‐4F This work provides facile strategy reduce devices.

Язык: Английский

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π–π Stacking Modulation via Polymer Adsorption for Elongated Exciton Diffusion in High‐Efficiency Thick‐Film Organic Solar Cells

Advanced Materials, Год журнала: 2024, Номер 36(21)

Опубликована: Фев. 22, 2024

Abstract Developing efficient organic solar cells (OSCs) with thick active layers is crucial for roll‐to‐roll printing. However, thicker often result in lower efficiency. This study tackles this challenge using a polymer adsorption strategy combined layer‐by‐layer approach. Incorporating insulator polystyrene (PS) into the PM6:L8‐BO system creates PM6+PS:L8‐BO blends, effectively suppressing trap states and extending exciton diffusion length mixed donor domain. Adding insulating polymers benzene rings to enhances π–π stacking of donors, boosting intermolecular interactions electron wave function overlap. results more orderly molecular stacking, longer lifetimes, higher lengths. The promoted long‐range leads high power conversion efficiencies 19.05% 18.15% blend films 100 300 nm thickness, respectively, as well respectable 16.00% 500 nm. These insights guide material selection better diffusion, offer method thick‐film OSC fabrication, promoting prosperous future practical mass production.

Язык: Английский

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Halogenation Strategy of Thiophene Derived Solvent Additives Enables Optimized Morphology for Organic Solar Cells with 19.17% Efficiency

Advanced Functional Materials, Год журнала: 2024, Номер 34(19)

Опубликована: Янв. 14, 2024

Abstract As simple and versatile tools, additives have been widely used to refine active layer morphology played a crucial role in boosting the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, three novel solvent named Th‐FSi, Th‐ClSi, Th‐BrSi with same backbone 2,5‐bis(trimethylsilyl)thiophene are designed synthesized by substituting different halogens fluorine, chlorine, bromine, respectively. Notably, Th‐ClSi exhibits more significant dipole moment engages non‐covalent interactions small‐molecule acceptor (SMA) L8‐BO, which slight adjustments intermolecular interaction, crystallinity, molecular packing PM6:L8‐BO layer. Consequently, OSCs incorporating outperform their Th‐FSi counterparts photo‐capturing, reduced energy loss, superior exciton dissociation, charge transfer properties, out‐coming yields an enhanced PCE 18.29%. Moreover, integrating near‐infrared absorbing SMA (BTP‐eC9) guest into matrix, absorption spectrum span 880–930 nm, resultant ternary achieve commendable 19.17%, ranking among highest efficiencies reported date is expanded. These findings underscore promise halogenated thiophene‐based as potent avenue for morphological fine‐tuning consequent enhancement OSCs.

Язык: Английский

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Oligothiophene Additive‐Assisted Morphology Control and Recombination Suppression Enable High‐Performance Organic Solar Cells

Advanced Energy Materials, Год журнала: 2024, Номер 14(11)

Опубликована: Янв. 9, 2024

Abstract Tuning the morphology through processing additives represents one of most promising strategies to boost performance organic solar cells (OSCs). However, it remains unclear how oligothiophene‐based solid influence molecular packing and OSCs. Here, two namely 2T 4T, are introduced into state‐of‐the‐art PM6:Y6‐based OSCs understand they film formation process, nanoscale morphology, photovoltaic performance. It is found that additive can improve both donor polymer non‐fullerene acceptor, resulting in lower Urbach energy reduced loss. Furthermore, blend with treatment displays enhanced domain purity a more favorable distribution acceptor materials vertical direction, which enhance charge extraction efficiency while simultaneously suppressing recombination. Consequently, processed realize 18.1% for devices. general applicability demonstrated, an impressive 18.6% PM6:L8‐BO‐based achieved. These findings highlight uncomplicated oligothiophenes have excellent potential fine‐adjustment active layer crucial future development

Язык: Английский

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Isomerization Engineering of Solid Additives Enables Highly Efficient Organic Solar Cells via Manipulating Molecular Stacking and Aggregation of Active Layer

Advanced Materials, Год журнала: 2024, Номер 36(33)

Опубликована: Июнь 20, 2024

Morphology control is crucial in achieving high-performance organic solar cells (OSCs) and remains a major challenge the field of OSC. Solid additive an effective strategy to fine-tune morphology, however, mechanism underlying isomeric solid additives on blend morphology OSC performance still vague urgently requires further investigation. Herein, two based pyridazine or pyrimidine as core units, M1 M2, are designed synthesized explore working OSCs. The smaller steric hindrance larger dipole moment facilitate better π-π stacking aggregation M1-based active layer. M1-treated all-small-molecule OSCs (ASM OSCs) obtain impressive efficiency 17.57%, ranking among highest values for binary ASM OSCs, with 16.70% M2-treated counterparts. Moreover, it imperative investigate whether isomerization engineering works state-of-the-art polymer D18-Cl:PM6:L8-BO-based devices achieve exceptional 19.70% (certified 19.34%), work provides deep insights into design clarifies potential optimizing device through additives.

Язык: Английский

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