Synergy Effect of Symmetry-Breaking and End-Group Engineering Enables 16.06% Efficiency for All-Small-Molecule Organic Solar Cells

Wang, Qian; Zhang, Xu; Miao, Yawei; Jiang, Xinyue; Wang, Xunchang; Zhang, Zhan; Lv, Zekun; Liu, Tao; Zou, Bingsuo; Xu, Huajun; Yang, Renqiang; Kan, Yuanyuan; Sun, Yanna; Gao, Ke

doi:10.1021/acsmaterialslett.3c01500

Cited by 3 publications

(2 citation statements)

References 55 publications

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“…This enhances π–π stacking, exciton diffusion, and charge transport . Consequently, BDT-T-based ASM OSCs have achieved a PCE of up to 16.0% …”

Section: Introductionmentioning

confidence: 99%

An Insight into the Mechanism of Alkyl Side-Chain Engineering of BTCN on Its Photovoltaic Properties─A Theoretical Study

Li,

Cao,

Peng

et al. 2024

J. Phys. Chem. C

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Organic photovoltaic materials featuring thiophenesubstituted benzo [1,2-b:4,5-b′]dithiophene (BDT-T) units show great potential. However, the influence of alkyl side-chain engineering on BDT-T units in these materials remains elusive. In this study, we focused on a high-performance small-molecule BTCN series with an acceptor−donor−acceptor architecture, where BDT-T serves as the donor. We systematically explored how varying the number and positions of alkyl chains on lateral thiophene rings affects the photovoltaic properties. The geometric parameters and ground and excited state properties were calculated using density functional theory (DFT) and time-dependent DFT (TDDFT). The experimentally observed differences in photovoltaic performance between BTCN-M and BTCN-O due to different substituted positions of the two alkyl chains can be explained well by our calculated data. Furthermore, the results show that, out of the BTCN series considered, BTCN-S1 in which the single-alkyl substitution is next to the sulfur atom of the lateral thiophene molecule could be a promising donor since it has the most negative average electrostatic potential and strongest light absorption in the visible region. Lastly, compared to double-alkyl-chain substitutions, single-chain substitution on the BDT-T unit can decrease the exciton binding energy but may increase the singlet−triplet energy differences in BTCNs. These findings offer valuable insights into alkyl side-chain engineering for optimizing BDT-T-based organic materials.

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“…This enhances π–π stacking, exciton diffusion, and charge transport . Consequently, BDT-T-based ASM OSCs have achieved a PCE of up to 16.0% …”

Section: Introductionmentioning

confidence: 99%

An Insight into the Mechanism of Alkyl Side-Chain Engineering of BTCN on Its Photovoltaic Properties─A Theoretical Study

Li,

Cao,

Peng

et al. 2024

J. Phys. Chem. C

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“…Organic solar cells (OSCs) exhibit substantial promise as they can directly convert solar power into electricity, offering exceptional features such as lightweight construction, flexibility, translucency, and more. − Proverbially, they can be categorized into polymer/small molecule, small molecule/polymer, all-polymer, and all-small-molecule OSCs based on the types of electron donor and acceptor materials. − In contrast to polymers, small molecules demonstrate distinct advantages with their well-defined molecular structures without batch-to-batch variations, easily tunable band gaps, facile synthesis, and purification process. − Considering these merits, all-small-molecule OSCs (ASM-OSCs) have garnered significant attention. Recently, the ASM-OSCs have made significant advancements in materials designing and morphology engineering, leading to power conversion efficiencies (PCEs) over 18% .…”

mentioning

confidence: 99%

Design of Halogenated Donors for Efficient All-Small-Molecular Organic Solar Cells

Zhang,

Chang,

Zhang

et al. 2024

ACS Materials Lett.

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Precise adjustment of the nanoscale morphology within the active layers is crucial for optimizing the photovoltaic performance of all-smallmolecule organic solar cells (ASM-OSCs), and the halogen substituent strategy for photovoltaic materials plays a vital role in the development of the morphology evolution. In this work, we systematically study a series of acceptor−donor−acceptor (A-D-A) type small-molecule donors by incorporating halogenation at the thienyl benzo[1,2-b:4,5-b′]dithiophene (BDT-T) donor core unit named BSTR-F, BSTR-Cl, and BSTR-Br. Such halogenation is demonstrated to induce a significant increase in the ionization potential, i.e., deeper HOMO, and more ordered packing property. Using N3 as the acceptor, the BSTR-F-based devices achieve a power conversion efficiency (PCE) up to 15.93%, compared with the control nonhalogenated donor BSTR-H-based devices of 13.80%, indicating that the suitable halogenation strategy could effectively promote the high performance of ASM-OSCs.

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

Miao,

Sun,

Zou

et al. 2024

Advanced Materials

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

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Synergy Effect of Symmetry-Breaking and End-Group Engineering Enables 16.06% Efficiency for All-Small-Molecule Organic Solar Cells

Cited by 3 publications

References 55 publications

An Insight into the Mechanism of Alkyl Side-Chain Engineering of BTCN on Its Photovoltaic Properties─A Theoretical Study

An Insight into the Mechanism of Alkyl Side-Chain Engineering of BTCN on Its Photovoltaic Properties─A Theoretical Study

Design of Halogenated Donors for Efficient All-Small-Molecular Organic Solar Cells

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

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