Side Chain Length and Interaction Mediated Charge Transport Networks of Non-Fullerene Acceptors for Efficient Organic Solar Cells

Fu, Yiwei; Wang, Liang; Guo, Chuanhang; Li, Donghui; Cai, Jinlong; Zhou, Bojun; Chen, Chen; Liu, Chenhao; Liu, Dan; Li, Wei; Wang, Tao

doi:10.1021/acsmaterialslett.2c00764

Cited by 12 publications

(12 citation statements)

References 43 publications

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“…[ 11–14 ] Regards that, it has been widely accepted that constructing favorable molecular packing to enable an efficient charge transport network is key to further enhance FFs to approach the Shockley–Queisser limit. [ 24‐30 ] As such, various molecular design strategies have been devoted to optimize the molecular packing of NFAs. For example, Wang et al.…”

Section: Introductionmentioning

confidence: 99%

Realizing an Unprecedented Fill Factor of 82.2% in Ternary Organic Solar Cells via Co‐Crystallization of Non‐Fullerene Acceptors

Chen

Wang

Sun

et al. 2023

Adv Funct Materials

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Ternary strategy is demonstrated as an efficient approach to achieve high short‐circuit current and open‐circuit voltage to boost the performance of organic solar cells (OSCs), however, the realization of high fill‐factor (FF) in ternary OSCs has been rare. In this study, three thiophene terminated non‐fullerene acceptors (NFAs) with methyl or chlorine substitutions on their end‐groups are designed and synthesized, and further incorporated into the state‐of‐the‐art PM6:L8‐BO system to construct ternary OSCs. Subtle changes in their chemical structures significantly modify the molecular packings of these thiophene terminated NFAs. While BTP‐ThMe and BTP‐ThCl have limited forms of dimer, versatile molecular dimers, including “Z” shaped D‐D, “S” shaped A‐A, and “F” shaped A‐D packings exist in BTP‐ThMeCl, which lead to the formation of compact 3D honey‐comb network and this is analogous to the host acceptor L8‐BO. This synergetic molecular packing between BTP‐ThMeCl and L8‐BO contributes to maintain the 3D charge transport network in the ternary system via the formation of NFA co‐crystals at the molecular level, and consequently realizing a maximum power conversion efficiency of 19.1% with a superior FF of 82.2%, which is the highest FF reported so far for OSCs.

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Section: Introductionmentioning

confidence: 99%

Realizing an Unprecedented Fill Factor of 82.2% in Ternary Organic Solar Cells via Co‐Crystallization of Non‐Fullerene Acceptors

Chen

Wang

Sun

et al. 2023

Adv Funct Materials

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“…As a result, BTP‐4Cl‐C9‐20‐based neat film showed the lowest electron mobility ( µ e ) and the corresponding OSCs obtained the lowest efficiency. [ 38 ]…”

Section: Introductionmentioning

confidence: 99%

“…As a result, BTP-4Cl-C9-20-based neat film showed the lowest electron mobility (μ e ) and the corresponding OSCs obtained the lowest efficiency. [38] Herein, we further use the sidechain engineering on Y6-1O to manipulate the molecular packing behaviors in solid state, especially in single-crystal state (see Figure 1). Thus, three Y6-1O derivatives, namely 1OBO-1, 1OBO-2, and 1OBO-3 are designed and synthesized.…”

Section: Introductionmentioning

confidence: 99%

Manipulating Crystal Stacking by Sidechain Engineering for High‐Performance N‐Type Organic Semiconductors

Chen,

Wu,

Ding

et al. 2023

Adv Funct Materials

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Y‐series non‐fullerene acceptors (NFAs) have achieved great progress in organic solar cells (OSCs). Most research attention is currently paid to their molecular engineering to improve the efficiency of OSCs. However, as n‐type organic semiconductors, the relationship between their molecular packing structures and charge transport properties is mostly ignored. Herein, it is clarified how the molecular packing of Y‐series NFAs fundamentally determines their charge transport properties by manipulating their crystal stacking via sidechain engineering. Therefore, branched alkyl/alkoxy substitutions are taken on a reference NFA (Y6‐1O), affording three derivatives, namely 1OBO‐1, 1OBO‐2, and 1OBO‐3. Results show that while the replacement of branched alkyl/alkoxy sidechains has little impact on optical properties and energy levels, it can change crystal stacking motifs significantly. The single crystal of Y6‐1O with all linear sidechains forms a 2D‐brickwork structure and shows lower mobility. In contrast, 1OBO‐2 with all branched sidechains exhibits a favorable 3D interpenetrating porous network, displaying an electron mobility of 1.42 cm2 V−1 s−1 in single‐crystal organic field‐effect transistors (SC‐OFETs). This value is among the highest for NFA‐based n‐type OFETs. This study not only reveals the fundamental structure–property relationships of Y‐series NFAs, but also suggests the potential of Y‐series NFAs for high‐performance n‐type organic semiconductors.

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“…Then molecular dynamics simulations (MDS) were utilized to clarify the molecular interactions between the third component with the host system. 43 By taking the host acceptor C5-16 as an example, the stacking configuration of dimers between C5-16 and another molecule, i.e. C5-16, ThMeCl-1, or ThMeCl-2, was studied.…”

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confidence: 99%

Isomerization Directed Molecular Packing toward Suppressing Energy Loss in Nonfullerene Ternary Solar Cells

Sun

Chen

Wang

et al. 2023

ACS Materials Lett.

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Organic semiconductors based upon conjugated frameworks are often isomeric and display distinct optoelectronic properties within minor structural variation. In this work, two isomeric nonfullerene acceptors (NFAs) ThMeCl-1 and ThMeCl-2, having the methyl and chlorine atoms attached on different positions of the electron-withdrawing end group, are synthesized and incorporated as the third component in ternary solar cells. Although these NFA isomers exhibit a similar bandgap, energy levels, and energy loss in their PM6 based binary devices, the efficiency enhancements in ternary devices differ significantly. Compared to ThMeCl-1, the incorporation of ThMeCl-2 in PM6:C5-16 solar cells enables less energy loss, leading to an extra 0.03 eV open-circuit voltage gain and a maximum efficiency increase from 17.8 to 18.9%. Grazing-incidence X-ray diffraction and molecular dynamics simulations reveal that this is attributed to the versatile intermolecular π−π stacking forms between ThMeCl-2 and the host NFA, which result in improved charge transport and suppressed recombination. This work provides a rational guidance for controlling the molecular packing in ternary systems to prepare high performance organic photovoltaics.

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Side Chain Length and Interaction Mediated Charge Transport Networks of Non-Fullerene Acceptors for Efficient Organic Solar Cells

Cited by 12 publications

References 43 publications

Realizing an Unprecedented Fill Factor of 82.2% in Ternary Organic Solar Cells via Co‐Crystallization of Non‐Fullerene Acceptors

Realizing an Unprecedented Fill Factor of 82.2% in Ternary Organic Solar Cells via Co‐Crystallization of Non‐Fullerene Acceptors

Manipulating Crystal Stacking by Sidechain Engineering for High‐Performance N‐Type Organic Semiconductors

Isomerization Directed Molecular Packing toward Suppressing Energy Loss in Nonfullerene Ternary Solar Cells

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