Improving Efficiency of Organic Solar Cells by Restricting the Rotation of Side Chain on Small Molecule Acceptor

Ouyang, Jinyang; Zhang, Bo; Zeng, Guang Sheng; Zhang, Jidong; Zhao, Xiaoli; Yang, Xiaoniu

doi:10.1002/solr.202000359

Cited by 10 publications

(13 citation statements)

References 56 publications

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“…[ 31 ] The large steric hindrance and free rotation for the side chains will disturb the intermolecular π–π stacking and lead to a low crystallinity. [ 55 ] Intermolecular aggregation often has a great influence on E b . for example, Wei et al [ 56 ] reported that the 3D packing crystal of the OSCs can effectively reduce E b with an extremely weak E b of 0.04 eV calculated in 4TIC.…”

Section: Effect Of the Structure Of Nfas On E B Of Excitonsmentioning

confidence: 99%

Exciton Binding Energy of Non‐Fullerene Electron Acceptors

Zhu

Zhao

Wang

et al. 2022

Adv Energy and Sustain Res

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The past three years have witnessed the power conversion efficiency (PCE) of organic solar cells (OSCs) rocketing to over 18%, due to outstanding advantages of non‐fullerene acceptors (NFAs). However, large exciton binding energy (E b) caused by strong Coulombic force is still one of the main limiting factors for high‐performance OSCs. Thus, it is critical to reduce the E b for further enhancement of device performance. Many strategies have been developed to reduce the E b of organic materials previously. In this perspective, the calculation methods for E b and the relationship between E b and voltage loss (V loss) are discussed. Then, the effects of the properties of small‐molecule acceptors on E b from the perspectives of fused‐ring donor cores, end groups, side chains, and molecular packing are discussed. Finally, the potential directions for reducing E b and pointing out the trade‐off between E b and bandgaps/miscibility are put forward. It is hoped that this perspective could provide a new thinking of a molecular design for the breakthrough of OSCs.

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Section: Effect Of the Structure Of Nfas On E B Of Excitonsmentioning

confidence: 99%

Exciton Binding Energy of Non‐Fullerene Electron Acceptors

Zhu

Zhao

Wang

et al. 2022

Adv Energy and Sustain Res

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“…This favorable stacking is beneficial to both the hole and electron transport, which will contribute to the higher FF. 36 Consequently, an outstanding PCE of 14.11% is achieved by the C8C8−4Cl-based OSCs with a V oc of 0.818 V, a J sc of 23.8 mA cm −2 , and an FF of 72.5%. It should be noted that our result is one of the best values ever reported in A−D−A′−D− A-type NFREAs (Figure S5).…”

Section: Optical and Electrochemicalmentioning

confidence: 97%

Simultaneous Tuning of Alkyl Chains and End Groups in Non-fused Ring Electron Acceptors for Efficient and Stable Organic Solar Cells

Luo

Jiang

Shan

et al. 2022

ACS Appl. Mater. Interfaces

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Fine-tuning the alkyl chains and end groups of non-fused ring electron acceptors (NFREAs) plays vital roles in the promotion of charge transfer (CT) and power conversion efficiency (PCE). In this work, we developed a series of A−D−A′−D−A-type NFREAs, which possess the same terminals (A), the cyclopentadithiophene unit (D), and the thieno[3,4-c]pyrrole-4,6-dione (A′). Despite the subtle difference in side chains and halogenated end groups, the six acceptors exhibit a considerable difference in the efficiency and device stability of the organic solar cells (OSCs). Among the molecules, chlorinated NFREAs show a broader light absorption than the fluorinated ones do. Compared with C8C8−4F (1-octylnonyl and fluorination) and C6C4−4Cl (2-butyloctyl and chlorination), C8C8−4Cl (1-octylnonyl and chlorination) exhibits a lower highest occupied molecular orbital level, higher electron mobility, and denser molecular packing. The OSCs based on PM6:C8C8−4Cl yield the best PCE of 14.11%, which is attributed to the faster charge transport, high miscibility, and preferable morphology. Moreover, the PM6:C8C8−4Cl devices retain 91.1% of the initial PCE after being placed in air with 67% relative humidity for 50 days. This work shows that the simultaneous optimization of side chains and end groups facilitates the CT and improves the stability in the OSCs, offering a novel view into the molecular design of A−D−A′−D−A-type NFREAs.

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“…This has a large influence on the PV performance in blends with the donor PBTIBDTT. The best PCE is achieved with α-branched 9-7 (12.1%), the lowest with the β-branched 9-8 (2.38%) …”

Section: Nine Fused Aromatic Ring Systemsmentioning

confidence: 98%

“…The best PCE is achieved with αbranched 9-7 (12.1%), the lowest with the β-branched 9-8 (2.38%). 537 Compound 9-10 (DTTC-4F) is very similar to 9-7, with the only difference being the use of octylphenyl instead of hexylphenyl side chains on the central core. 538 Solar cells with PM6 gave PCE values of almost 14%.…”

Section: Eight Fused Aromatic Ring Systemsmentioning

confidence: 99%

Recent Progress in the Design of Fused-Ring Non-Fullerene Acceptors─Relations between Molecular Structure and Optical, Electronic, and Photovoltaic Properties

Schweda

Reinfelds

Hofstadler

et al. 2021

ACS Appl. Energy Mater.

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Organic solar cells are on the dawn of the next era. The change of focus toward non-fullerene acceptors has introduced an enormous amount of organic n-type materials and has drastically increased the power conversion efficiencies of organic photovoltaics, now exceeding 18%, a value that was believed to be unreachable some years ago. In this Review, we summarize the recent progress in the design of ladder-type fused-ring non-fullerene acceptors in the years 2018–2020. We thereby concentrate on single layer heterojunction solar cells and omit tandem architectures as well as ternary solar cells. By analyzing more than 700 structures, we highlight the basic design principles and their influence on the optical and electrical structure of the acceptor molecules and review their photovoltaic performance obtained so far. This Review should give an extensive overview of the plenitude of acceptor motifs but will also help to understand which structures and strategies are beneficial for designing materials for highly efficient non-fullerene organic solar cells.

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Improving Efficiency of Organic Solar Cells by Restricting the Rotation of Side Chain on Small Molecule Acceptor

Cited by 10 publications

References 56 publications

Exciton Binding Energy of Non‐Fullerene Electron Acceptors

Exciton Binding Energy of Non‐Fullerene Electron Acceptors

Simultaneous Tuning of Alkyl Chains and End Groups in Non-fused Ring Electron Acceptors for Efficient and Stable Organic Solar Cells

Recent Progress in the Design of Fused-Ring Non-Fullerene Acceptors─Relations between Molecular Structure and Optical, Electronic, and Photovoltaic Properties

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