Intermolecular Arrangement of Fullerene Acceptors Proximal to Semiconducting Polymers in Mixed Bulk Heterojunctions

Wang, Chao; Nakano, Kyohei; Lee, Hsiao Fang; Chen, Yujiao; Hong, You‐lee; Nishiyama, Yusuke; Tajima, Kazuo

doi:10.1002/anie.201801173

Cited by 11 publications

(13 citation statements)

References 37 publications

(56 reference statements)

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“…The definitions of atom types for PBDB‐T, PC 71 BM, and ITIC are provided in Figure S12, Supporting Information and ref. , and the missing torsion potential parameters for PBDB‐T and ITIC were derived from DFT calculations (Figure S13, Supporting Information and ref. ).…”

Section: Methodsmentioning

confidence: 99%

“…Critical to photovoltaic operation is the donor/acceptor (D/A) interfaces, where photogenerated excitons, namely, Coulombically bounded electron‐hole pairs are dissociated and separated into free charges . Although it is still a challenge to directly probe the heterogeneous, nanoscale, disordered, and buried interfaces at the atomistic level by optical X‐ray and photoelectron techniques, there is a general consensus that tuning the D/A interfaces is essential to maximize exciton dissociation (ED) and minimize charge recombination (CR) for achieving high power conversion efficiencies (PCEs) …”

mentioning

confidence: 99%

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Atomistic Insight Into Donor/Acceptor Interfaces in High‐Efficiency Nonfullerene Organic Solar Cells

Han

Guo

et al. 2018

Solar RRL

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Donor/acceptor (D/A) interfaces play a crucial role in photoelectric conversion for organic solar cells. However, it is impossible to experimentally probe D/A interfaces at the atomistic level to date, in particular for organic solar cells based on nonfullerene acceptors due to their anisotropic structures. In this work, we have investigated the interfacial structures of a representative D-A copolymer donor PBDB-T with a well-known A-D-A structured nonfullerene acceptor ITIC, in comparison with a fullerene acceptor PC 71 BM, by means of atomistic simulations. It is found that owing to different side-chain steric hindrance between the polymer A and D units, both acceptors are more likely to approach the polymer A units, and more apparently for ITIC in consideration of the size and shape matching between the acceptors and the polymer A and D units. Importantly, docking of ITIC with polymer occurs mainly through local π-π interaction between the terminal moieties of ITIC and the A units of the polymer, and such interfacial structures are favorable for efficient exciton dissociation. Our work sheds light on the impact of sidechain nature and location as well as acceptor structures on D/A interfaces and charge-transfer dynamics, which will be very helpful for further improving the performance of organic photovoltaics.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Atomistic Insight Into Donor/Acceptor Interfaces in High‐Efficiency Nonfullerene Organic Solar Cells

Han

Guo

et al. 2018

Solar RRL

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“…[13] Chen et al demonstrated that the side chain regiochemistry has a significant influence on the intrinsic aggregation properties of polymer donors, the domain size of blend films, and the performance of the resulting nonfullerene PSCs. [15] The side chain pattern that allows an electron-accepting unit of polymer main chain positioned in close proximity to fullerene produced higher performance in PSC devices. [15] The side chain pattern that allows an electron-accepting unit of polymer main chain positioned in close proximity to fullerene produced higher performance in PSC devices.…”

Section: Introductionmentioning

confidence: 99%

Alkyl Chain Length Effects of Polymer Donors on the Morphology and Device Performance of Polymer Solar Cells with Different Acceptors

Pang

Zhang

Duan

et al. 2019

Advanced Energy Materials

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The development of nonfullerene acceptors has brought polymer solar cells into a new era. Maximizing the performance of nonfullerene solar cells needs appropriate polymer donors that match with the acceptors in both electrical and morphological properties. So far, the design rationales for polymer donors are mainly borrowed from fullerene‐based solar cells, which are not necessarily applicable to nonfullerene solar cells. In this work, the influence of side chain length of polymer donors based on a set of random terpolymers PTAZ‐TPD10‐Cn on the device performance of polymer solar cells is investigated with three different acceptor materials, i.e., a fullerene acceptor [70]PCBM, a polymer acceptor N2200, and a fused‐ring molecular acceptor ITIC. Shortening the side chains of polymer donors improves the device performance of [70]PCBM‐based devices, but deteriorates the N2200‐ and ITIC‐based devices. Morphology studies unveil that the miscibility between donor and acceptor in blend films depends on the side chain length of polymer donors. Upon shortening the side chains of the polymer donors, the miscibility between the donor and acceptor increases for the [70]PCBM‐based blends, but decreases for the N2200‐ and ITIC‐based blends. These findings provide new guidelines for the development of polymer donors to match with emerging nonfullerene acceptors.

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“…[41][42][43][44] To further improve the performance of SM OSCs to meet commercial viability, it is highly desirable to unravel what makes the A-π -D-π -A structures special and how to tune the local packing morphology for efficient charge generation by side-chain engineering. These substituents are often detrimental to charge transport and can also influence the donor/acceptor (D/A) intermolecular arrangements.…”

Section: Doi: 101002/adts201800091mentioning

confidence: 99%

“…[41,42,[45][46][47][48][49][50][51][52][53] Nevertheless, faster ED obtained by improving D/A intermolecular interactions are generally accompanied by more severe CR and slower CS. It has been well recognized that the electronic-structure properties of active molecules and D/A complexes at the interfaces are critical to maximize exciton dissociation (ED) and charge separation (CS) and to minimize charge recombination (CR).…”

Section: Doi: 101002/adts201800091mentioning

confidence: 99%

Rationalizing Small‐Molecule Donor Design toward High‐Performance Organic Solar Cells: Perspective from Molecular Architectures

Han

2018

Advcd Theory and Sims

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Tuning donor/acceptor interfacial arrangements and electron-transfer processes in the active layers is crucial to improve the performance of organic solar cells (OSCs). Here, the impact of different molecular architectures (i.e., A-π -D-π -A, D-π-A-π -D and π-A-D-A-π ) of the donors on the interfacial arrangements and electronic processes in small-molecule (SM) OSCs is elucidated by means of multiscale theoretical simulations. An A-π-D-π-A structured donor with sizable terminal units, extended π bridges, and bulky side groups on the backbone core is proved to be able to simultaneously obtain both efficient charge generation and migration as well as suppressed charge recombination, thus paving the way for the rational design of electron donors toward high-performance SM OSCs.Solution-processed bulk heterojunction (BHJ) organic solar cells (OSCs) have achieved remarkable progress in the past decade. [1][2][3][4][5][6][7][8][9] For fullerene-based small-molecule (SM) OSCs, power conversion efficiencies (PCEs) have exceeded 11%, which is in stark contrast to the highest value of 1% in 2006 (Figure 1a). [4,5,[10][11][12][13][14][15][16][17][18][19] This significant improvement is attributed to the great efforts in developing new SM donors and device optimizations. [20][21][22][23][24][25][26][27][28] To date, three typical push-pull molecular structures, namely, D-π -A-π -D, π -A-D-A-π , and A-π -D-π -A, have been successfully used as SM donors. It is noteworthy that most of the donors with PCEs over 9% are of A-π -D-π -A structures. [4,5,18,[29][30][31][32][33] Inspired by the success of fullerene-based SM OSCs, nonfullerene counterparts have shown faster progress in the past few years (Figure 1a). [8,9,[34][35][36][37] Similarly, for nonfullerene SM OSCs with PCEs over 9%, both the donors and acceptors adopt A-π -D-π -A and/or Aπ -A structures. [8,9,[38][39][40] To realize solution processing in organic solvents, alkyl side chains are necessary to attach to the

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Intermolecular Arrangement of Fullerene Acceptors Proximal to Semiconducting Polymers in Mixed Bulk Heterojunctions

Cited by 11 publications

References 37 publications

Atomistic Insight Into Donor/Acceptor Interfaces in High‐Efficiency Nonfullerene Organic Solar Cells

Atomistic Insight Into Donor/Acceptor Interfaces in High‐Efficiency Nonfullerene Organic Solar Cells

Alkyl Chain Length Effects of Polymer Donors on the Morphology and Device Performance of Polymer Solar Cells with Different Acceptors

Rationalizing Small‐Molecule Donor Design toward High‐Performance Organic Solar Cells: Perspective from Molecular Architectures

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