Significant enhancement of the photovoltaic performance of organic small molecule acceptors <i>via</i> side-chain engineering

Su, Wenyan; Fan, Qunping; Guo, Xia; Chen, Juan; Wang, Yan; Wang, Xiaohui; Dai, Ping; Ye, Chennan; Bao, Xiaoguang; Ma, Wei; Zhang, Maojie; Li, Yongfang

doi:10.1039/c8ta01509k

Cited by 37 publications

(19 citation statements)

References 61 publications

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“…In addition, meta ‐substituted m ‐INPOIC exhibits more flexible molecular geometry, mainly due to the meta ‐substituted alkoxylphenyl groups–attached INP core. The inward constriction toward molecular backbone may facilitate the intermolecular π–π stacking and unify molecular orientation of m ‐INPOIC . The flexible geometry of m ‐INPOIC may help to enhance the solubility of material.…”

Section: Resultsmentioning

confidence: 99%

Molecular Orientation Unified Nonfullerene Acceptor Enabling 14% Efficiency As‐Cast Organic Solar Cells

Feng

Song

Zhang

et al. 2019

Adv Funct Materials

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Molecular orientation and π-π stacking of nonfullerene acceptors (NFAs) determine its domain size and purity in bulk-heterojunction blends with a polymer donor. Two novel NFAs featuring an indacenobis(dithieno[3,2-b:2′,3′-d] pyrrol) core with meta-or para-alkoxyphenyl sidechains are designed and denoted as m-INPOIC or p-INPOIC, respectively. The impact of the alkoxyl group positioning on molecular orientation and photovoltaic performance of NFAs is revealed through a comparison study with the counterpart (INPIC-4F) bearing para-alkylphenyl sidechains. With inward constriction toward the conjugated backbone, m-INPOIC presents predominant face-on orientation to promote charge transport. The as-cast organic solar cells (OSCs) by blending m-INPOIC and PBDB-T as active layers exhibit a power conversion efficiency (PCE) of 12.1%. By introducing PC 71 BM as the solid processing-aid, the ternary OSCs are further optimized to deliver an impressive PCE of 14.0%, which is among the highest PCEs for as-cast single-junction OSCs reported in literature to date. More attractively, PBDB-T:m-INPOIC:PC 71 BM based OSCs exhibit over 11% PCEs even with an active layer thickness over 300 nm. And the devices can retain over 95% of PCE after storage for 20 days. The outstanding tolerance to film thickness and outstanding stability of the as-cast devices make m-INPOIC a promising candidate NFA for large-scale solutionprocessable OSCs.

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Section: Resultsmentioning

confidence: 99%

Molecular Orientation Unified Nonfullerene Acceptor Enabling 14% Efficiency As‐Cast Organic Solar Cells

Feng

Song

Zhang

et al. 2019

Adv Funct Materials

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“…Among them, MOIT‐M showed a larger absorption coefficient, more ordered staking, and enhanced electron mobility. Therefore, the OSCs with the MOIT‐M : PTZ1 blend film prepared without any additives exhibited PCEs up to 11.61 % …”

Section: Nfsmas For Additive‐free Oscsmentioning

confidence: 96%

Additive‐Free Non‐Fullerene Organic Solar Cells

et al. 2019

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With the extensive research efforts paid over the past 30 years, the power conversion efficiency of organic solar cells (OSCs) has been steadily improved from below 1 % to greater than 16 %. While fullerene derivatives have traditionally played a dominant role as acceptor materials in the first two decades, the distinctive advantages of non‐fullerene acceptors, such as tunable energy levels, broad absorption, and improved device stability, have rendered them as the mainstream acceptors in OSCs, recently. However, in most cases, processing additives are required for morphology optimization of the photoactive layer, and these additives usually possess high boiling point, which makes it difficult to remove them completely. The residual additives would accelerate performance deterioration, leading to poor device stability. Furthermore, the tedious optimization of additives complicates device fabrication and decreases performance reproducibility. In this review, we summarize the recent works based on non‐fullerene OSCs without using additives, affording insights into materials design and device fabrication for enabling highly efficient additive‐free non‐fullerene OSCs, which should be critical for the practical applications of OSCs.

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“…To design novel SMAs with desirable properties, such as wide and intense absorption to enhance short‐circuit current ( J sc ) and suitable energy levels to improve open‐circuit voltage ( V oc ), the effects of modification of core units, atom substitutions, bridging units, end groups and side chains of NFAs on the photovoltaic performance of corresponding devices have been widely investigated. Among them, the replacement of hydrogen atom with chlorine atom in atomic substitutions has attracted great attention and has been widely used in molecular design .…”

Section: Background and Originality Contentmentioning

confidence: 99%

A Non‐Fullerene Acceptor with Chlorinated Thienyl Conjugated Side Chains for High‐Performance Polymer Solar Cells via Toluene Processing

Fang

et al. 2020

Chin. J. Chem.

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Summary of main observation and conclusion Small molecular acceptors (SMAs) BTC‐2F and BTH‐2F, based on heptacyclic benzodi(cyclopentadithiophene) electron‐donating core (CBT) with chlorinated‐thienyl conjugated and thienyl conjugated side chains, respectively, are designed and synthesized. Compared with non‐chlorine acceptor BTH‐2F, BTC‐2F exhibits slightly blue‐shifted absorption spectra, similar the lowest unoccupied molecular orbital (LUMO) (–3.91 eV), deeper highest occupied molecular orbital (HOMO) energy level and higher electron mobility than that of BTH‐2F. PM6, a wide bandgap polymer, is selected as the donor material to construct bulk heterojunction polymer solar cells processed with nonhalogenated solvent toluene. The optimized PM6:BTC‐2F‐based device presents a 12.9% power conversion efficiency (PCE), while the PCE of PM6:BTH‐2F‐based device is only 11.3%. The results suggest that it is an effective strategy to optimize the photoelectric properties of SMAs by incorporating chlorine atom into the conjugated side chains.

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Significant enhancement of the photovoltaic performance of organic small molecule acceptors via side-chain engineering

Abstract: The photovoltaic performance of PSC based on PTZ1 and IT-M is significantly improved by modulating side-chain architecture of IT-M from para-hexylphenyl to para-hexyloxylphenyl to meta-hexyloxylphenyl and a high PCE of 11.6% has been achieved.

Cited by 37 publications

References 61 publications

Molecular Orientation Unified Nonfullerene Acceptor Enabling 14% Efficiency As‐Cast Organic Solar Cells

Molecular Orientation Unified Nonfullerene Acceptor Enabling 14% Efficiency As‐Cast Organic Solar Cells

Additive‐Free Non‐Fullerene Organic Solar Cells

A Non‐Fullerene Acceptor with Chlorinated Thienyl Conjugated Side Chains for High‐Performance Polymer Solar Cells via Toluene Processing

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