Thienothiophene-based copolymers for high-performance solar cells, employing different orientations of the thiazole group as a π bridge

Zhu, Dangqiang; Bao, Xichang; Zhu, Qianqian; Gu, Chuantao; Qiu, Meng; Wen, Shuguang; Wang, Junyi; Yang, Renqiang

doi:10.1039/c6ee03186b

Cited by 110 publications

(95 citation statements)

References 43 publications

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“…As the Tz units increased, the HOMO energy level decreased. The results verified that the Cl atom that was substituted on the side chain and the Tz unit that was incorporated into the main chain could significantly reduce the HOMO energy level, which could favor high V OC in photovoltaic devices …”

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 57%

“…With the introduction of a thiazole (Tz) moiety, the HOMO energy level significantly decreased, and the backbone planarity increased. Accordingly, the V OC gradually increased from 0.68 V for polymer PBDTTT‐E‐T without thiazole to 0.78 V for polymer PBTzT‐4 with one thiazole unit and 0.83 V for polymer PTBTz‐2 with two units . In addition, the position of the halogen atom also has a significant impact on intermolecular self‐assembly of the conjugated polymers .…”

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 99%

“…The synthetic route and the related characterization of the chlorinated BDT unit (M1) are presented in the Experimental Section (Supporting Information). Meanwhile, the quinoid monomers M2‐M4 were prepared based on a previously reported method . Three target polymers, PBClTTz‐0, PBClTTz‐1, and PBClTTz‐2, were obtained via the Stille coupling reaction between monomer M1 and different TT acceptors, respectively, which were further purified via the Soxhlet extraction.…”

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 99%

“…As another Tz unit was introduced, the optical absorption blueshifted further, which could be ascribed to the reduced ratio of the quinoid structure. In addition, compared to a nonchlorinated analogy, the polymers exhibited a hypsochromic shift of 30 to 40 nm, which is attributed to restrained intermolecular interactions caused by the larger atomic radius of chlorine atom . Temperature‐dependent UV–vis absorption spectroscopy was employed to investigate the aggregation behavior of the polymers in a dilute chlorobenzene solution (10 −5 m ) at temperatures ranging from room temperature to 100 °C (Figure S3, Supporting Information).…”

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 99%

See 3 more Smart Citations

Chlorinated Polymers for Efficient Solar Cells with High Open Circuit Voltage: The Influence of Different Thiazole Numbers

Yuan

Wang

Zhu

et al. 2019

Macromol. Rapid Commun.

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The chlorination strategy has gradually become a promising approach to improve the open circuit voltage (VOC) in polymer solar cells. In this work, by using an efficient thiazole‐induced strategy in a polymer backbone, three thieno[3,4‐b]thiophene (TT)‐based polymers—PBClTTz‐0, PBClTTz‐1, and PBClTTz‐2—are designed and synthesized with a Cl‐substituted benzodithiophene (BDT) moiety and a thiazole unit as a π spacer. As expected, all of the polymers show a desirable open circuit voltage (VOC) of >0.94 V in the solar cells; specifically, the voltage can reach 1.01 V for polymer PBClTTz‐2 with two thiazole moieties. In addition, due to the excellent surface morphology and weak recombination of the active layer, photovoltaic devices based on PBClTTz‐1 with one thiazole unit exhibit the highest power conversion efficiency (PCE) of 8.42%, which is noticeably superior to the fluorinated analogue PBClTTz‐0 (6.85%). This work reveals the influence of the thiazole unit in a quinoid polymer backbone and confirms that the Donor‐Acceptor(π)‐Quinoid strategy is a promising construction method in molecular design.

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Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 57%

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 99%

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 99%

Section: The Absorption Properties and Energy Values Of The Polymersmentioning

confidence: 99%

See 2 more Smart Citations

Chlorinated Polymers for Efficient Solar Cells with High Open Circuit Voltage: The Influence of Different Thiazole Numbers

Yuan

Wang

Zhu

et al. 2019

Macromol. Rapid Commun.

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“…To facilitate the calculation, side alkyl chains were simplify to methyl groups. [41] For the electron distribution, it can be observed that the HOMO surface of the polymers delocalize in both TBD and accept units and the LUMO surface of the polymers mainly localize in the acceptor units. The moderate twisting geometry was beneficial to improve the solubility and inhibit strong aggregation of the corresponding polymers.…”

Section: Resultsmentioning

confidence: 98%

A Maverick Asymmetrical Backbone with Distinct Flanked Twist Angles Modulating the Molecular Aggregation and Crystallinity for High Performance Nonfullerene Solar Cells

Wang

Dou

et al. 2018

Advanced Energy Materials

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energy source. [1][2][3][4] The past few years have witnessed the rapid progress of nonfullerene n-type acceptors and the PCE of nonfullerene-based PSCs devices have already surpassed 13% for single-junction devices. [5][6][7][8][9] To achieve efficient nonfullerene PSCs and mature fully from research into cost effective products, it is of critical importance not only to design high-performance small molecular acceptors (SMAs), but also to develop matching donor polymers, as well as to deeply understand the mechanism of the coordinated microstructure interactions between donor and acceptor components. [10][11][12][13][14][15] Key and fundamental strategies for designing high-effciency nonfullerene PSC devices are absorption spectrum and energy level. The donor and acceptor components should possess complementary absorptions and high extinction coefficient to enhance light harvesting to achieve high J SC . [16,17] The matching energy levels are crucial for donor and acceptor to ensure efficient driving force of exciton dissociation, to minimize voltage loss and thus to guarantee high V OC . However, the troublesome tradeoff between high V OC and J SC is inevitable which is the big challenge for further improving the PSCs performance. [18,19] In addition, the most difficult and complicated problem is how to precisely modulate the microstructure of the blending system. The donor should exhibit good morphology compatibility with the acceptor, including suitable crystallinity, appropriate aggregation, face-on orientation, and moderate domain size, and thus to achieve excellent charge transport and high fill factor (FF). [20][21][22] Therefore, establishing universal and general guideline of rational designing compatible D/A structure is extremely urgent and important for nonfullerene PSCs.Benzo[1,2-b:4,5-b′]dithiophene (BDT) and dithieno[2,3d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene (DTBDT) are the dominant backbones for donor polymers because of their planar framework, showing the most high performance in PSCs. [23][24][25][26][27][28][29][30] Most researchers focus on the side chain engineering of BDT-and DTBDT-based polymers and demonstrate that optimized side-chain can easily control polymer packing In this work, a new asymmetrical backbone thienobenzodithiophene (TBD) containing four aromatic rings is designed, and then four polymers PTBD-BZ, PTBD-BDD, PTBD-FBT, and PTBD-Tz are synthesized. The planar and high degree of π-conjugation configuration can guarantee effective charge carrier transport and the distinct flanked dihedral angles between the TBD core and conjugated side chain can subtly regulate the molecular aggregation and crystallinity. The four polymer/3,9-bis(2-methylene-(3-(1,1dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]-dithiophene (ITIC) blending films exhibit predominantly face-on orientation. The photovoltaic devices based on wide bandgap polymers PTBD-BZ and PTBD-BDD achieve power conversion efficiencies (PCEs) as high as 12.02% and...

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Side Group Engineering of Small Molecular Acceptors for High‐Performance Fullerene‐Free Polymer Solar Cells: Thiophene Being Superior to Selenophene

Gao

Ming

et al. 2017

Adv Funct Materials

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Side group of ITIC‐like small molecular acceptor (SMA) plays a critical role in crystallization property. In this article, two new SMAs with n‐hexylthienyl and n‐hexylselenophenyl as side chain, namely ITCPTC‐Th and ITCPTC‐Se, are designed and synthesized by employing newly developed thiophene‐fused ending group (CPTCN). And thiophene and selenophene side group substituted effects of SMA‐based fullerene‐free polymer solar cells (PSCs) are investigated. A stronger σ‐inductive effect between selenophene side group and electron‐donating backbone endows ITCPTC‐Se with better optical absorption and higher LUMO level, ITCPTC‐Th‐based PSCs deliver a higher power conversion efficiency of 10.61%. Charge transport and collection, recombination loss mechanism, and morphology of blend films are intensively studied. These results confirm that side group substituted effects of SMAs are multiple and thiophene is a superior option to selenophene as aromatic side group of ITIC‐like SMAs.

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Thienothiophene-based copolymers for high-performance solar cells, employing different orientations of the thiazole group as a π bridge

Abstract: The new strategy, employing thiazole as a π bridge into the backbone of quinoid polymers, enhanced the VOC and photovoltaic performance.

Cited by 110 publications

References 43 publications

Chlorinated Polymers for Efficient Solar Cells with High Open Circuit Voltage: The Influence of Different Thiazole Numbers

Chlorinated Polymers for Efficient Solar Cells with High Open Circuit Voltage: The Influence of Different Thiazole Numbers

A Maverick Asymmetrical Backbone with Distinct Flanked Twist Angles Modulating the Molecular Aggregation and Crystallinity for High Performance Nonfullerene Solar Cells

Side Group Engineering of Small Molecular Acceptors for High‐Performance Fullerene‐Free Polymer Solar Cells: Thiophene Being Superior to Selenophene

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