Synthesis and Characterization of Fluorenone-Based Donor-Acceptor Small Molecule Organic Semiconductors for Organic Field-Effect Transistors

Lee, Jeongyeon; Yun, Chang-Koo; Reddy, M. Rajeshkumar; Ho, Dongil; Kim, Choongik; Seo, Sang‐Hun

doi:10.1007/s13233-020-8123-z

Cited by 6 publications

(2 citation statements)

References 44 publications

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“…UV–vis absorption spectra of R -C10 film vs temperature are displayed in Figure a, and those of the RS 1:1-C10 racemate are displayed in Figure c. There is consensus that the weak absorption between 400 and 520 nm in mono- and dithienyl fluorenone is due to intramolecular charge transfer (ICT) between the thiophene donor and fluorenone acceptor. − In the UV the two most obvious effects of the Iso-Col h and Iso-Col h - Fddd phase changes are increasing absorbance of the π–π* band around 290 nm and weakening of the n–π* shoulder around 350 nm. The former could be attributed to closer contacts between aromatic groups along the column, facilitating energy transfer and hence depletion of excited states.…”

Section: Resultsmentioning

confidence: 99%

Enantiomers Self-Sort into Separate Counter-Twisted Ribbons of the Fddd Liquid Crystal─Antiferrochirality and Parachirality

Wang,

Li,

Cseh

et al. 2023

J. Am. Chem. Soc.

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The recently discovered orthorhombic liquid crystal (LC) phase of symmetry Fddd is proving to be widespread. In this work, a chiral hydroxybutyrate linkage is inserted into the molecular core of hexacatenar rodlike compounds, containing a thienylfluorenone fluorophore. In addition to more usual tools, the methods used include grazing-incidence X-ray scattering, modulated differential scanning calorimetry (DSC), flash DSC with rates up to 6000 K/s, and chiro-optical spectroscopies using Mueller matrix method, plus conformational mapping. Although pure R and S enantiomers form only a strongly chiral hexagonal columnar LC phase (Col h *), the racemic mixture forms a highly ordered Fddd phase with 4 right-and 4 left-handed twisted ribbon-like columns traversing its large unit cell. In that structure, the two enantiomers locally deracemize and self-sort into the columns of their preferred chirality. The twisted ribbons in Fddd, with a 7.54 nm pitch, consist of stacked rafts, each containing ∼2 side-by-side molecules, the successive rafts rotated by 17°. In contrast, an analogous achiral compound forms only the columnar phase. The multiple methods used gave a comprehensive picture and helped in-depth understanding not only of the Fddd phase but also of the "parachiral" Col h * in pure enantiomers with irregular helicity, whose chirality is compared to the magnetization of a paramagnet in a field. Unusual short-range ordering effects are also described. An explanation of these phenomena is proposed based on conformational analysis. Surprisingly, the isotropic−columnar transition is extremely fast, completing within ∼20 ms. A clear effect of phase on UV−vis absorption and emission is observed.

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Section: Resultsmentioning

confidence: 99%

Enantiomers Self-Sort into Separate Counter-Twisted Ribbons of the Fddd Liquid Crystal─Antiferrochirality and Parachirality

Wang,

Li,

Cseh

et al. 2023

J. Am. Chem. Soc.

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“…Our research team previously reported a study that improved conjugation by additional thiophene rings. In order to achieve the same effect, thiophene rings were attached to DTT moiety [50]. The solution-processability of the compounds was enhanced with a linear (octyl) or branched (2-ethylhexyl) terminal chain, and the solution-shearing (SS) method was performed to produce semiconductor thin film.…”

Section: Introductionmentioning

confidence: 99%

Development of Dithieno[3,2-b:2′,3′-d]thiophene (DTT) Derivatives as Solution-Processable Small Molecular Semiconductors for Organic Thin Film Transistors

Choi

Jang

et al. 2021

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Novel solution-processable dithieno[3,2-d:2′,3′-d]thiophene (DTT) derivatives with alkylated thiophene or alkyl chain substituents, 2,6-bis(5-octylthiophen-2-yl)dithieno[3,2-b:2′,3′-d]thiophene (compound 1), 2,6-bis(5-(2-ethylhexyl)thiophen-2-yl)dithieno[3,2-b:2′,3′-d]thiophene (compound 2), and 2,6-dioctyldithieno[3,2-b:2′,3′-d]thiophene (compound 3), have been synthesized and employed as small molecular organic semiconductors for organic field-effect transistors (OFETs). All compounds exhibited good thermal stability over 290 °C, while different side groups of DTT compounds afforded different melting temperatures. The molecular orbital energy levels were experimentally and theoretically calculated, and their trend was almost the same. The developed compounds were employed as active layers for top-contact/bottom-gate OFETs with average charge carrier mobility as high as 0.10 cm2/Vs and current on/off ratio > 107 in ambient atmosphere. Notably, DTT derivative with linear alkyl chain (-octyl) substituents showed the best device performance. High device performance could be attributed to the large grains and continuous surface coverages as well as high film texture of the corresponding semiconductor films.

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Well-Defined ABA Triblock Copolymers Containing Carbazole and Ethynyl Groups: Living Anionic Polymerization, Postpolymerization Modification, and Thermal Cross-Linking

Kang

2021

Macromol. Res.

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Synthesis and Characterization of Fluorenone-Based Donor-Acceptor Small Molecule Organic Semiconductors for Organic Field-Effect Transistors

Cited by 6 publications

References 44 publications

Enantiomers Self-Sort into Separate Counter-Twisted Ribbons of the Fddd Liquid Crystal─Antiferrochirality and Parachirality

Enantiomers Self-Sort into Separate Counter-Twisted Ribbons of the Fddd Liquid Crystal─Antiferrochirality and Parachirality

Development of Dithieno[3,2-b:2′,3′-d]thiophene (DTT) Derivatives as Solution-Processable Small Molecular Semiconductors for Organic Thin Film Transistors

Well-Defined ABA Triblock Copolymers Containing Carbazole and Ethynyl Groups: Living Anionic Polymerization, Postpolymerization Modification, and Thermal Cross-Linking

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