Solution processable star-shaped molecules with a triazine core and branching thienylenevinylenes for bulk heterojunction solar cells

Huang, Chien‐Yi; Lee, Wan-Hua; Lee, Rong-Ho

doi:10.1039/c4ra07139e

Cited by 21 publications

(14 citation statements)

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“…Since then, small molecule materials containing Cz as the D unit have gained growing interest and shown promising results. At least, three main structures A-D-A [19,20], D-A [21,22], and D-A-D [23,24,25,26] have been introduced. However, more experimental studies are needed to discover new state-of-the-art small molecule electron donors and, in particular, to gain systematic information about the relationships between their chemical structures, material properties, and performance in OSC applications.…”

Section: Introductionmentioning

confidence: 99%

Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties

et al. 2018

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Highlights•Novel D-A and A-D-A type small molecule electron donors were synthesized •Characterization by computational, electrochemical, and spectroscopic methods •A-D-A type materials were tested as active layer components in OSC devices •Relations between molecular structures and properties are studied and discussed Abstract Efficient synthetic methods for carbazole-based small molecule electron donors with donoracceptor (D-A) and A-D-A type structures were developed. In order to study the relation between chemical structures and material properties, the prepared compounds were characterized in detail using absorption spectroscopy, differential pulse voltammetry, and computational methods. In addition, symmetrical A-D-A type compounds were tested as an active layer component in bulk heterojunction based organic solar cell (OSC) devices with conventional structure. The results show that the two compound types have many similar properties. However, the extended molecular structure of A-D-A type compounds offer better film forming properties and higher molar absorption coefficients compared with the D-A type materials. Furthermore, the attachment of fluoro substituents in the A units has a positive effect on all solar cell device parameters. Moreover, the computational studies revealed that the molecular structures are twisted between the central carbazole D unit and -bridge which may result in inefficient intramolecular charge transfer and, also, relatively limited short-circuit currents in OSC devices.Recently, we reported a synthetic pathway to BT-based building blocks [27]. Since then, we have further developed the synthetic strategy and, here, we present the syntheses of two unsymmetrical D-A and two symmetrical A-D-A type small molecules. In these compounds, Cz acts as a D unit and either BT or its fluoro-substituted derivative as an A unit. Thiophene and thiazole have been used as a -bridge in between the D and A units. In order to find out how the changes in molecular structures affect the material properties, the prepared D-A and A-D-A type small molecule compounds have been characterized by spectroscopic, electrochemical, and computational methods.Moreover, the symmetrical A-D-A type compounds have been tested as electron donor materials in BHJ-based OSC devices. Experimental sectionCommercial reagents were used as received. 2-(3-Hexylthiophen-2-yl)-5-(4,4,5,5tetramethyl-1,3,2-dioxaborolan-2-yl)thiazole and compound 3b were synthesized using the previously published methods [27]. The chemical structures of new compounds were characterized by using NMR and HRMS techniques. Melting points (reported as peak values) of compounds 5a, 5b, 6a, and 6b were measured by using Mettler Toledo DSC 1 apparatus with a TSO800GC1 Gas Control system. Samples of 1.6-2.2 mg were placed in 40 L Al crucibles with pierced lids. The DSC scans were carried out from 5 o C to 300 o C at the heating rate of 20 o C min -1 under a nitrogen flow of 60 mL min -1 . Syntheses2.1.1. Synthesis of 4-bromo-5-fluoro-7-(5-hexylthiophen-2-yl...

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Section: Introductionmentioning

confidence: 99%

Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties

et al. 2018

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“…Lee and co‐workers reported the synthesis of star‐shaped molecules 49 and 50 , which employed an acceptor 1,3,5‐triazine ring as a core, conjugated thienylenevinylene as a bridging unit, and di‐ tert ‐butyltriphenylamine or di‐ tert ‐butylcarbazole units at their periphery . A SM cross‐coupling reaction was utilized as a key step in the preparation of these compounds.…”

Section: Carbon−carbon Bond Formationmentioning

confidence: 99%

“…[9] In this context, 2-acetylthiophene (1)w as treated with ethylenediamine (15)a nd TFAatr eflux in nitromethanetod eliver the trimerized product. Subsequent bromination with NBS produced the desired tribromoc ompound (16). Tribromothiophene derivative 16 was subjected to ap alladium-catalyzed SM cross-coupling reactiont oa fford aryl derivatives, such as compounds 5 and 17.T he photophysical properties of these star-shapedm olecules were also studied.…”

Section: Suzuki-miyaura Cross-coupling Reactionsmentioning

confidence: 99%

“…2019, 14,1356 -1403 www.chemasianj.org 2019 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim ing unit, and di-tert-butyltriphenylamine or di-tert-butylcarbazole units at their periphery. [16] AS Mc ross-coupling reaction was utilized as ak ey step in the preparation of these compounds.M oreover,t he authors also studied the photovoltaic properties of thesec ompounds and explored their application in organic solar cells. These compounds also exhibited excellent thermals tability.…”

Section: Suzuki-miyaura Cross-coupling Reactionsmentioning

confidence: 99%

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Synthetic Approaches to Star‐Shaped Molecules with 1,3,5‐Trisubstituted Aromatic Cores

Kotha

Meshram

Panguluri

et al. 2019

Chemistry An Asian Journal

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Herein, we summarize the synthetic approaches that have been developed for the synthesis of star‐shaped molecules. Typically, to design such highly functionalized molecules, simple building blocks are first assembled through trimerization reactions, starting from commercially available starting materials. Then, these building blocks are synthetically manipulated to generate extended star‐shaped molecules. We also discuss the syntheses of star‐shaped molecules that contain 2,4,6‐trisubstituted 1,3,5‐triazine or 1,3,5‐trisubstituted benzene rings as a central core and diverse substituted styrene, phenyl, and fluorene derivatives at their periphery, which endows these molecules with extended conjugation. A variety of metal‐catalyzed reactions, such as Suzuki, Buchwald–Hartwig, Sonogashira, Heck, and Negishi cross‐coupling reactions, as well as metathesis, have been employed to functionalize a range of star‐shaped molecules. The methods described herein will be helpful for designing a wide range of intricate compounds that are highly valuable in the fields of supramolecular chemistry and materials science. Owing to space limitations, we will not cover all of the publications on this topic. Instead, we will focus on examples that were reported by our research group and other relevant recent literature. Apart from the trimerization sequence, this Minireview has been structured based on the key reactions that were used to prepare the star‐shaped molecules and other higher analogues. Finally, some examples that do not fit into this classification are discussed.

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“…In this paper, we explore the substrate scope of the Kumada C − C coupling reaction between various electrophilic aryl fluorides and thiophen‐2‐yl magnesium bromide. The Sp 2 ‐C − F bond is successfully activated by the strong electron‐withdrawing triazine group . The polymerization scope was investigated.…”

Section: Introductionmentioning

confidence: 99%

Nickel‐catalysed Kumada polycondensation of di‐functionalized Grignard reagent with aryl fluoride

Han

Zong

Liu

et al. 2016

Polymer International

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A nickel catalyst promoted the polymerization between various Grignard reagents with 2-phenyl-4,6-bi(4-fluorophenyl)-1,3,5triazine. The reaction scope was thoroughly investigated and fully characterized. The Sp 2 -C − F bond was successfully activated by the triazine group in Kumada coupling reactions. Also, di-Grignard reagents showed higher activity than mono-Grignard reagents. The reaction scope results reveal that a Grignard reagent with strong nucleophilicity and aryl fluoride with strong electrophilicity are necessary to lead to Kumada polycondensation of oligothiophenes with aryl fluoride. In this work, polymerization between di-functionalized oligothiophene Grignard reagents with aryl fluoride was first conducted. The weight-average molecular weight is high, up to 14.8 kDa. The -conjugated polymers obtained exhibit emission colours of blue, green and yellow with efficient photoluminescence.

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Solution processable star-shaped molecules with a triazine core and branching thienylenevinylenes for bulk heterojunction solar cells

Cited by 21 publications

References 57 publications

Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties

Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties

Synthetic Approaches to Star‐Shaped Molecules with 1,3,5‐Trisubstituted Aromatic Cores

Nickel‐catalysed Kumada polycondensation of di‐functionalized Grignard reagent with aryl fluoride

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