Radiation-induced conductivity in polymerized and nonpolymerized columnar aggregates of phthalocyanine

Schouten, Pieter G.; Warman, John M.; Haas, Matthijs P. de; Pol, J.F. van der; Zwikker, Jan W.

doi:10.1021/ja00049a039

Cited by 115 publications

(43 citation statements)

References 8 publications

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“…Due to their high viscosity in the columnar phases, there are no applications for these materials as such in display devices but the negative birefringence films formed by polymerized nematic DLCs have been commercialized as compensation foils to enlarge the viewing angle of commonly used twisted nematic liquid crystal displays. Nevertheless, they receive increasing attention in the field of one-dimensional conductors [16][17][18]. Self-organization of discotic molecules into columnar liquid crystalline phases is a subject of great practical interest since these phases do show, for appropriately chemically tailored molecules, specific physical properties such as a good electronic conductivity along the column axes.…”

Section: Introductionmentioning

confidence: 99%

Characteristic dielectric parameters of columnar discotic hexa-n-alkoxyanthraquinones

et al. 2008

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Temperature-dependent dielectric spectroscopy of resynthesized discotic compounds, rufigallol hexa-n-alkoxylates for n ¼ 6, 7, 8, 9 having wide temperature range (470 C) hexagonal columnar mesophase has been carried out in the frequency range of 10 Hz to 10 MHz. The mesophase and their transition temperatures have been determined by using polarizing microscope and differential scanning calorimeter. Dielectric permittivity parallel (" 0 jj ) and perpendicular (" 0 ? ) to column have been determined. Using these data, dielectric anisotropy (Á" ¼ " 0 jj À " 0 ? ) has been found to be positive throughout the entire range of the Col h phase for all of the four compounds of this series. No relaxation phenomenon is found in the frequency range of 10 Hz to 10 MHz. The DC conductivity of these compounds has been found to be rather low ($10 À10 -10 À11 S-m À1 ). All the electrical parameters show odd-even effect with the variation of n.

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Section: Introductionmentioning

confidence: 99%

Characteristic dielectric parameters of columnar discotic hexa-n-alkoxyanthraquinones

et al. 2008

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“…In early 1990s, as an alternate method to generate charge carriers, researchers employed ionizing radiation/photoirradiation in chemically pure (nondoped) DLC molecules and measured the charge carrier mobility by PR-TRMC or TOF technique. Porphyrin and phthalocyanine derivatives were the first examples of DLCs studied for the conductivity by a PR-TRMC method [36,37]. In the year 1993, Adam et al measured photoinduced charge-carrier mobility of 1 × 10 −3 cm 2 V −1 s −1 in the columnar phase of hexapentyloxytriphenylene (2b) by the TOF technique [19].…”

Section: Discotic Liquid Crystals With Highmentioning

confidence: 99%

Self-assembled 1D Semiconductors: Liquid Crystalline Columnar Phase

Mathews

Achalkumar

2015

Anisotropic Nanomaterials

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Organic semiconducting materials have emerged as potential alternative to inorganic silicon based semiconductors for the production of low-cost, flexible and light weight plastic electronic devices. When compared with crystalline and polymeric structures, liquid crystalline (LC) ordering in organic semiconductors favors their self-assembly into large area monodomain thin-film structures with carrier mobilities in the range from 10

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“…Alternatively, in the early 1990s researchers were successful in employing ionizing radiation/photoirradiation as a means to generate charge carriers in chemically pure (nondoped) DLC molecules and measured the mobility by PR-TRMC or TOF technique. Porphyrin and phthalocyanine derivatives were the first examples of DLCs to be studied for the conductivity by a PR-TRMC method [36,37]. In 1993, Adam et al measured photoinduced charge-carrier mobility of 1 × 10 −3 cm 2 V −1 s −1 in the columnar phase of hexapentyloxytriphenylene (2b) by the TOF technique [29].…”

Section: Discotic Liquid Crystals With High Charge-carrier Mobilitymentioning

confidence: 99%

“…Subsequent studies revealed the role of chain length and metal ion on phase transition temperatures, mesophase range, and carrier mobilities. Initial charge-carrier [36,37]. By using the TOF technique, Ohta and coworkers found ambipolar charge transport (negative charge mobility of 2.4 × 10 −3 cm 2 V −1 s −1 and a positive mobility of 2.2 × 10 −3 cm 2 V −1 s −1 ) in the Col h of a Cu-phthalocyanine compound 10 [57].…”

Section: Discotic Liquid Crystals With High Charge-carrier Mobilitymentioning

confidence: 99%

Self‐Organized Discotic Liquid Crystals as Novel Organic Semiconductors

Mathews¹,

Li²

2011

Self‐Organized Organic Semiconductors

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Organic semiconductors are being intensely investigated and incorporated in device applications such as thin-film transistors, light-emitting diodes, solar cells, and sensors [1,2]. Organic molecules offer the advantage of low-cost synthesis and easy manufacture of large-area thin films by solution processing for the fabrication of a new generation of low-cost, lightweight, and flexible devices that would be inaccessible by conventional methods using inorganic semiconducting materials. The efficiency of these devices is directly related to the mobility of the charges achievable in the conducting layer fabricated by solution-processing techniques such as spin-coating, casting, or printing at ambient conditions exploitable on an industrial scale [3]. A number of different molecular and structural features (chemical purity, solubility, degree of crystallinity, energy band gap, absorption, emission, charge generation, and transport, etc.) have to be combined for optimizing device performance. On the basis of morphology of the materials in the active layers, they can be broadly classified into crystalline, amorphous, and liquid crystalline semiconductors. The highest charge-carrier mobilities (>2 cm 2 V −1 s −1 ) in organic systems have been measured in organic single crystals of pentacene and rubrene [4,5]. However, it is difficult to grow single-crystalline thin films. Charge mobilities in the polycrystalline films of polymeric semiconducting materials such as oligothiophenes, poly(phenylenevinylene), poly(thiophene), and poly(fluorine) compounds have reached values exceeding that of amorphous silicon (>1.0 cm 2 V −1 s −1 ) [6,7]. Thermal sublimation in vacuum is a common method for depositing polymeric

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Radiation-induced conductivity in polymerized and nonpolymerized columnar aggregates of phthalocyanine

Cited by 115 publications

References 8 publications

Characteristic dielectric parameters of columnar discotic hexa-n-alkoxyanthraquinones

Characteristic dielectric parameters of columnar discotic hexa-n-alkoxyanthraquinones

Self-assembled 1D Semiconductors: Liquid Crystalline Columnar Phase

Self‐Organized Discotic Liquid Crystals as Novel Organic Semiconductors

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