Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation

Fan, Qunping; An, Qiaoshi; Lin, Yuanbao; Xia, Yuxin; Li, Qian; Zhang, Ming; Su, Wenyan; Peng, Wenhong; Zhang, Chunfeng; Liu, Feng; Hou, Lintao; Zhu, Weiguo; Yu, Daquan; Xiao, Min; Moons, Ellen; Zhang, Fujun; Anthopoulos, Thomas D.; Inganäs, Olle; Wang, Ergang

doi:10.1039/d0ee01828g

Cited by 180 publications

(152 citation statements)

References 83 publications

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“…Organic solar cells (OSCs) as a green photon-to-current conversion technology have shown great potential as a clean energy source because it can be fabricated into large-area, light-weight, flexible and/ or semitransparent devices through costeffective solution processing method. [1][2][3] In the past few years, multiple contributions stemming from material design [4][5][6][7][8][9][10][11] and device engineering [12][13][14][15][16][17] have greatly improved the performance of OSCs to achieve over 16% certified power conversion efficiencies (PCEs) for single-junction devices. [18][19][20][21][22] However, the prospect of commercialization of OSCs is still lagging behind that inorganic silicon and hybrid perovskite solar cells due to their large energy loss (E loss ) in the charge generation processes.…”

Section: Doi: 101002/aenm202003177mentioning

confidence: 99%

Asymmetric Acceptors Enabling Organic Solar Cells to Achieve an over 17% Efficiency: Conformation Effects on Regulating Molecular Properties and Suppressing Nonradiative Energy Loss

Gao

et al. 2020

Advanced Energy Materials

126

120

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Y6, as a state‐of‐the‐art nonfullerene acceptor (NFA), is extensively optimized by modifying its side chains and terminal groups. However, the conformation effects on molecular properties and photovoltaic performance of Y6 and its derivatives have not yet been systematically studied. Herein, three Y6 analogs, namely, BP4T‐4F, BP5T‐4F, and ABP4T‐4F, are designed and synthesized. Owing to the asymmetric molecular design strategies, three representative molecular conformations for Y6‐type NFAs are obtained through regulating the lateral thiophene orientation of the fused core. It is found that conformation adjustment imposes comprehensive effects on the molecular properties in neat and blend films of these NFAs. As a result, organic solar cells (OSCs) fabricated with PM6:BP4T‐4F, PM6:BP5T‐4F, and PM6:ABP4T‐4F show high power conversion efficiency of 17.1%, 16.7%, and 15.2%, respectively. Interestingly, these NFAs with different conformations also show reduced energy loss (Eloss) in devices via gradually suppressed nonradiative Eloss. Moreover, by employing a selenium‐containing analog, CH1007, as the complementary third component, ternary OSCs based on PM6:BP5T‐4F:CH1007 (1:1.02:0.18) achieve a 17.2% efficiency. This work helps shed light on engineering the molecular conformation of NFAs to achieve high efficiency OSCs with reduced voltage loss.

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Section: Doi: 101002/aenm202003177mentioning

confidence: 99%

Asymmetric Acceptors Enabling Organic Solar Cells to Achieve an over 17% Efficiency: Conformation Effects on Regulating Molecular Properties and Suppressing Nonradiative Energy Loss

Gao

et al. 2020

Advanced Energy Materials

126

120

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“…Compared to the PYF‐T‐based all‐PSCs, the Y‐OD‐FBr‐based devices exhibit a reduced V OC of 0.84 V, a decent J SC of 23.23 mA cm −2 , a comparable FF of 68.23%, and a lower PCE of 13.32%, which is due to the extra bromination effect on the energy levels and absorption, thus resulting in a ≈6% decrement in the PCE with the similar trend as previous report. [ 52 ] Moreover, we conducted the shelf‐life stability experiments of the PYF‐T‐, PY‐T‐ ,and Y‐OD‐FBr‐based encapsulated devices (Figure S10, Supporting Information), in which the PYF‐T‐based devices demonstrated robust performance after 200 h with only a 5% decrease while the PY‐T‐based ones exhibited inferior stability degraded by 10% and a degraded PCE of 20% for PM6:Y‐OD‐FBr based device. The different thermal stabilities of all‐PSC and SMA‐OCS systems might be mainly due to the synergistic effects of the morphology evolution and interface attenuation.…”

Section: Figurementioning

confidence: 99%

Fluorinated End Group Enables High‐Performance All‐Polymer Solar Cells with Near‐Infrared Absorption and Enhanced Device Efficiency over 14%

Han

et al. 2020

Advanced Energy Materials

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As an emerging sustainable technology for harnessing solar energy, polymer solar cells (PSCs) have attracted extensive research attention due to their outstanding advantages, such as low cost, mechanical flexibility, and facile large-area fabrication. [1-7] Through the various strategies including molecular modulation on smallmolecular acceptors (SMAs), morphology optimization and interfacial engineering, the bulk-heterojunction devices based on polymer donors and SMAs have realized impressive power conversion efficiencies (PCEs) over 17%. [8-14] Among these achievements, Y6-series SMAs, which feature an A′-DAD-A′ structure, have demonstrated multiple cases of high-performance PSCs with optimized morphology and low energy loss. [15-17] Compared to SMA-based devices, all-PSCs provide additional merits such as high morphological stability, superior Fluorination of end groups has been a great success in developing efficient small molecule acceptors. However, this strategy has not been applied to the development of polymer acceptors. Here, a dihalogenated end group modified by fluorine and bromine atoms simultaneously, namely IC-FBr, is first developed, then employed to construct a new polymer acceptor (named PYF-T) for all-polymer solar cells (all-PSCs). In comparison with its non-fluorinated counterpart (PY-T), PYF-T exhibits stronger and red-shifted absorption spectra, stronger molecular packing and higher electron mobility. Meanwhile, the fluorination on the end groups down-shifts the energy levels of PYF-T, which matches better with the donor polymer PM6, leading to efficient charge transfer and small voltage loss. As a result, an all-PSC based on PM6:PYF-T yields a higher power conversion efficiency (PCE) of 14.1% than that of PM6:PY-T (11.1%), which is among the highest values for all-PSCs reported to date. This work demonstrates the effectiveness of fluorination of end-groups in designing high-performance polymer acceptors, which paves the way toward developing more efficient and stable all-PSCs.

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“…A major contributor to this improvement was the incorporation of the acceptor–(donor–acceptor–donor)–acceptor (A–DAD–A) electron‐deficient type polymerization unit in the polymer acceptor. [ 6–10 ]…”

Section: Introductionmentioning

confidence: 99%

Configurational Isomers Induced Significant Difference in All‐Polymer Solar Cells

Wang

Chen

Xie

et al. 2021

Adv Funct Materials

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The design of polymer acceptors plays an essential role in the performance of all‐polymer solar cells. Recently, the strategy of polymerized small molecules has achieved great success, but most polymers are synthesized from the mixed monomers, which seriously affects batch‐to‐batch reproducibility. Here, a method to separate γ‐Br‐IC or δ‐Br‐IC in gram scale and apply the strategy of monomer configurational control in which two isomeric polymeric acceptors (PBTIC‐γ‐2F2T and PBTIC‐δ‐2F2T) are produced is reported. As a comparison, PBTIC‐m‐2F2T from the mixed monomers is also synthesized. The γ‐position based polymer (PBTIC‐γ‐2F2T) shows good solubility and achieves the best power conversion efficiency of 14.34% with a high open‐circuit voltage of 0.95 V when blended with PM6, which is among the highest values recorded to date, while the δ‐position based isomer (PBTIC‐δ‐2F2T) is insoluble and cannot be processed after parallel polymerization. The mixed‐isomers based polymer, PBTIC‐m‐2F2T, shows better processing capability but has a low efficiency of 3.26%. Further investigation shows that precise control of configuration helps to improve the regularity of the polymer chain and reduce the π–π stacking distance. These results demonstrate that the configurational control affords a promising strategy to achieve high‐performance polymer acceptors.

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Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation

Abstract: Obtaining both high open-circuit voltage (Voc) and short-circuit current density (Jsc) has been a major challenge for efficient all-polymer solar cells (all-PSCs). Herein, we developed a polymer acceptor PF5-Y5 with...

Cited by 180 publications

References 83 publications

Asymmetric Acceptors Enabling Organic Solar Cells to Achieve an over 17% Efficiency: Conformation Effects on Regulating Molecular Properties and Suppressing Nonradiative Energy Loss

Asymmetric Acceptors Enabling Organic Solar Cells to Achieve an over 17% Efficiency: Conformation Effects on Regulating Molecular Properties and Suppressing Nonradiative Energy Loss

Fluorinated End Group Enables High‐Performance All‐Polymer Solar Cells with Near‐Infrared Absorption and Enhanced Device Efficiency over 14%

Configurational Isomers Induced Significant Difference in All‐Polymer Solar Cells

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