Enhanced Hole‐Transporting Behavior of Discotic Liquid‐Crystalline Physical Gels

Hirai, Yuki; Monobe, Hirosato; Mizoshita, Norihiro; Moriyama, Masaya; Hanabusa, Kenji; Shimizu, Yo; Kato, Takashi

doi:10.1002/adfm.200701313

Cited by 79 publications

(58 citation statements)

References 91 publications

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“…However, the charge carrier transport in these systems can be improved. It was reported that the mobility of discotic triphenylenes can be increased though the formation of physical gels using a low molecular-weight gelator [14] or by complementary mixtures [15] Figure 6. The intra-columnar charge mobilities in the hexagonal, columnar mesophase (D h ) of various discotic compounds:…”

Section: à4mentioning

confidence: 99%

Liquid Crystalline Ordering and Charge Transport in Semiconducting Materials

Pisula¹,

Zorn²,

Chang³

et al. 2009

Macromol. Rapid Commun.

374

276

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Organic semiconducting materials offer the advantage of solution processability into flexible films. In most cases, their drawback is based on their low charge carrier mobility, which is directly related to the packing of the molecules both on local (amorphous versus crystalline) and on macroscopic (grain boundaries) length scales. Liquid crystalline ordering offers the possibility of circumventing this problem. An advanced concept comprises: i) the application of materials with different liquid crystalline phases, ii) the orientation of a low viscosity high temperature phase, and, iii) the transfer of the macroscopic orientation during cooling to a highly ordered (at best, crystalline-like) phase at room temperature. At the same time, the desired orientation for the application (OLED or field-effect transistor) can be obtained. This review presents the use of molecules with discotic, calamitic and sanidic phases and discusses the sensitivity of the phases with regard to defects depending on the dimensionality of the ordered structure (columns: 1D, smectic layers and sanidic phases: 2D). It presents ways to systematically improve charge carrier mobility by proper variation of the electronic and steric (packing) structure of the constituting molecules and to reach charge carrier mobilities that are close to and comparable to amorphous silicon, with values of 0.1 to 0.7 cm(2) · V(-1) · s(-1) . In this context, the significance of cross-linking to stabilize the orientation and liquid crystalline behavior of inorganic/organic hybrids is also discussed.

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Section: à4mentioning

confidence: 99%

Liquid Crystalline Ordering and Charge Transport in Semiconducting Materials

Pisula¹,

Zorn²,

Chang³

et al. 2009

Macromol. Rapid Commun.

374

276

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“…The issue of flexible chain length in defining material characteristics has been discussed multiple times for semiconducting and/or supramolecular materials. [22,[24][25][26] However, comparatively few works have addressed structureproperty relations of molecular ferroelectrics in a systematic manner. [8,19,27] One of the few studies focusing on proper organic ferroelectric materials is by Kishikawa et al, who probed ferroelectric columnar hexagonal liquid crystalline urea with C 4 H 9 to C 16 H 33 long alkyl chains.…”

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confidence: 99%

Tuning the Ferroelectric Properties of Trialkylbenzene‐1,3,5‐tricarboxamide (BTA)

Urbanavičiūtė

Meng

Cornelissen

et al. 2017

Adv Elect Materials

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This study demonstrates how simple structural modification of a prototypical organic ferroelectric molecule can be used to tune its key ferroelectric properties. In particular, it is found that shortening the alkyl chain length of trialkylbenzene-1,3,5-tricarboxamide (BTA) from C18H37 to C6H13 causes an increase in depolarization activation energy (approximate to 1.1-1.55 eV), coercive field (approximate to 25-40 V mu m(-1)), and remnant polarization (approximate to 20-70 mC m(-2)). As the polarization enhancement far exceeds the geometrically expected factor, these observations are attributed to an increase in the intercolumnar interaction. The combination of the mentioned characteristics results in a record polarization retention time of close to three months at room temperature for capacitor devices of the material having the shortest alkyl chain. The long retention and the remnant polarization that is as high as that of P(VDF:TrFE) distinguish the BTA-C6 material from other small molecular organic ferroelectrics and make it a perspective choice for applications that require cheap, flexible, and lightweight ferroelectrics.

Funding Agencies|NWO Nano program; Vetenskapsradet; Swedish Government Strategic Research Area in Materials Science on Functional Materials at the Linkping University (Faculty Grant SFO Mat LiU) [2009 00971]

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“…In recent years, the fibrous supramolecular polymer network combining with the electrically switchable liquid crystal (LC) system have been developed as soft functional materials -LC physical gels [7][8][9][10]. The LC physical gels have been widely applied in various electro-optical devices, such as switchable scattering devices [11][12][13][14], LC semiconductors with high mobility [15,16], and stabilization of the orientation of ferroelectric LCs [17], etc. In particular, fast-response switching in twisted nematic (TN) cells based on the aid of fibrous polymer network have attracted more and more interests for their potential for improving the quality of LC displays (LCDs) [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

The Function of Self-Assembled Polyfluorene-Based π-Conjugated Supramolecular Structures Formed in Twisted Nematic Liquid Crystals

Kuo

Chen

Wang

et al. 2015

Molecular Crystals and Liquid Crystals

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We demonstrate that the supramolecular structure can be formed through the fibrous self-assembly of the polyfluorene-based polymer F8BT in liquid crystal (LC) 5CB. With the utility of alignment layer, the F8BT molecules can be aligned and formed oriented polymer network. We found that the presence of oriented polymer network makes twisted nematic LC exhibit excellent electro-optical properties (EO) of driving voltage reduction and EO bump peak elimination. The polyfluorene-based supramolecular structure provides the function of stabilizing LC molecules. We consider this functional selfassembled network has potential to apply in various devices for the ability of improving performance in operating property.

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Enhanced Hole‐Transporting Behavior of Discotic Liquid‐Crystalline Physical Gels

Cited by 79 publications

References 91 publications

Liquid Crystalline Ordering and Charge Transport in Semiconducting Materials

Liquid Crystalline Ordering and Charge Transport in Semiconducting Materials

Tuning the Ferroelectric Properties of Trialkylbenzene‐1,3,5‐tricarboxamide (BTA)

The Function of Self-Assembled Polyfluorene-Based π-Conjugated Supramolecular Structures Formed in Twisted Nematic Liquid Crystals

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