An A2–π–A1–π–A2-type small molecule donor for high-performance organic solar cells

A new A2–π–A1–π–A2-type small-molecule donor using a strong electron-withdrawing unit as the central unit was synthesized and its photovoltaic performance was investigated.

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With PBDB-T as the Donor, the PCE of Non-Fullerene Organic Solar Cells Based on Small Molecule INTIC Increased by 52.4%

Materials ◽

10.3390/ma13061324 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1324 ◽

Cited By ~ 1

Author(s):

Weifang Zhang ◽

Zicha Li ◽

Suling Zhao ◽

Zheng Xu ◽

Bo Qiao ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Short Circuit ◽

Photovoltaic Performance ◽

Short Circuit Current ◽

Production Costs ◽

Higher Carrier Mobility ◽

Carrier Transportation

At present, most high-performance non-fullerene materials are centered on fused rings. With the increase in the number of fused rings, production costs and production difficulties increase. Compared with other non-fullerenes, small molecule INTIC has the advantages of easy synthesis and strong and wide infrared absorption. According to our previous report, the maximum power conversion efficiency (PCE) of an organic solar cell using PTB7-Th:INTIC as the active layer was 7.27%. In this work, other polymers, PTB7, PBDB-T and PBDB-T-2F, as the donor materials, with INTIC as the acceptor, are selected to fabricate cells with the same structure to optimize their photovoltaic performance. The experimental results show that the optimal PCE of PBDB-T:INTIC based organic solar cells is 11.08%, which, thanks to the open voltage (VOC) increases from 0.80 V to 0.84 V, the short circuit current (JSC) increases from 15.32 mA/cm2 to 19.42 mA/cm2 and the fill factor (FF) increases from 60.08% to 67.89%, then a 52.4% improvement in PCE is the result, compared with the devices based on PTB7-Th:INTIC. This is because the PBDB-T:INTIC system has better carrier dissociation and extraction, carrier transportation and higher carrier mobility.

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All-small-molecule organic solar cells with over 14% efficiency by optimizing hierarchical morphologies

Nature Communications ◽

10.1038/s41467-019-13292-1 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 73

Author(s):

Ruimin Zhou ◽

Zhaoyan Jiang ◽

Chen Yang ◽

Jianwei Yu ◽

Jirui Feng ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

High Efficiency ◽

Bulk Heterojunction ◽

Photovoltaic Performance ◽

Photovoltaic System ◽

Active Layers ◽

Donor Acceptor

AbstractThe high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.

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Asymmetrical squaraines for high-performance small-molecule organic solar cells with a short circuit current of over 12 mA cm−2

Chemical Communications ◽

10.1039/c5cc00704f ◽

2015 ◽

Vol 51 (28) ◽

pp. 6133-6136 ◽

Cited By ~ 30

Author(s):

Yao Chen ◽

Youqin Zhu ◽

Daobin Yang ◽

Qian Luo ◽

Lin Yang ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Short Circuit ◽

Photovoltaic Performance ◽

Short Circuit Current ◽

Squaric Acid ◽

Squaraine Dyes

Asymmetrical squaraine dyes with two aryl groups directly linked to the squaric acid core were synthesized, and exhibited excellent photovoltaic performance.

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Nonfullerene Small-Molecule Acceptors with Extended Optical Absorption Based on the “Spliced” Strategy for Organic Solar Cells

Organic Materials ◽

10.1055/s-0039-3402049 ◽

2019 ◽

Vol 01 (01) ◽

pp. 071-077

Author(s):

Di Zhou ◽

Zhilin Liu ◽

Dangqiang Zhu ◽

Xiyue Yuan ◽

Xichang Bao ◽

...

Keyword(s):

Solar Cells ◽

Optical Absorption ◽

Band Gap ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Photovoltaic Performance ◽

Wide Band ◽

End Capping ◽

New Perspective

How to broaden the optical absorption of photovoltaic materials is one of the key issues in the design of high-performance organic solar cells. Nowadays, the sunlight of 400–550 nm wavelength range is not effectively utilized for most small-molecule nonfullerene acceptors. In this work, we proposed the “spliced” strategy of combining the acceptor–donor–acceptor type narrow band-gap small molecules and wide-band-gap perylene diimide (PDI) moieties via a flexible alkyl chain linkage, which could give the superposition effect of the absorption spectra, and three small-molecule acceptors (S1, S2, and S3) were designed based on various end-capping groups with different electron withdrawing abilities. Encouragingly, the as-constructed molecules can well make use of 400–550 nm sunlight with two independent absorption regions. Meanwhile, the aggregation of S1 with a highly planar end-capping group was dominated by both the PDI unit and main skeleton, while S2 and S3 exhibited PDI-controlled aggregation. When fabricated into organic solar cells, S1-based devices achieved a superior efficiency of 3.41% in comparison with those of the other two. The poor photovoltaic performance could be attributed to severe PDI aggregation, which can hinder the charge transfer through the main skeletons. This work could provide a new perspective to modulate optical absorption through the spliced strategy.

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Design of All-Small-Molecule Organic Solar Cells Approaching 14% Efficiency via Isometric Terminal Alkyl Chain Engineering

Energies ◽

10.3390/en14092505 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2505

Author(s):

Haiyan Chen ◽

Hua Tang ◽

Dingqin Hu ◽

Yiqun Xiao ◽

Jiehao Fu ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

High Performance ◽

Alkyl Chain ◽

Photovoltaic Performance ◽

Engineering Process ◽

Transport Channel ◽

Fine Tune ◽

Molecular Stacking

Morphology is crucial to determining the photovoltaic performance of organic solar cells (OSCs). However, manipulating morphology involving only small-molecule donors and acceptors is extremely challenging. Herein, a simple terminal alkyl chain engineering process is introduced to fine-tune the morphology towards high-performance all-small-molecule (ASM) OSCs. We successfully chose a chlorinated two-dimension benzo[1,2-b:4,5-b′]dithiophene (BDT) central unit and two isomeric alkyl cyanoacetate as the end-capped moieties to conveniently synthesize two isomeric small-molecule donors, namely, BT-RO-Cl and BT-REH-Cl, each bearing linear n-octyl (O) as the terminal alkyl chain and another branched 2-ethylhexyl (EH) as the terminal alkyl chain. The terminal alkyl chain engineering process provided BT-RO-Cl with 13.35% efficiency and BT-REH-Cl with 13.90% efficiency ASM OSCs, both with Y6 as the electron acceptor. The successful performance resulted from uniform phase separation and the favorable combination of face-on and edge-on molecular stacking of blended small-molecule donors and acceptors, which formed a fluent 3D transport channel and thus delivered high and balanced carrier mobilities. These findings demonstrate that alkyl chain engineering can finely control the morphology of ASM OSCs, and provides an alternative for the optimal design of small-molecule materials towards high-performance ASM OSCs.

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Developing high-performance small molecule organic solar cells via a large planar structure and an electron-withdrawing central unit

Chemical Communications ◽

10.1039/c6cc07927j ◽

2017 ◽

Vol 53 (2) ◽

pp. 451-454 ◽

Cited By ~ 16

Author(s):

Hongtao Zhang ◽

Yongtao Liu ◽

Yanna Sun ◽

Miaomiao Li ◽

Bin Kan ◽

...

Keyword(s):

Solar Cells ◽

Small Molecule ◽

Organic Solar Cells ◽

Building Block ◽

High Performance ◽

Planar Structure ◽

Central Unit ◽

Donor Material

We designed and synthesized a new small molecule donor material named DR3TBDD using an electron-withdrawing unit BDD as the central building block. A PCE of 9.53% with a highVocof around 1 V was achieved.

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