Transient photocurrent in amorphous selenium and nematic liquid crystal double layers

Murakami, Shuichi; Naito, Hiroyoshi; Okuda, Masahiro; Sugimura, Akihiko

doi:10.1063/1.359795

Cited by 62 publications

(33 citation statements)

References 15 publications

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“…10,11 In fact, papers published after the discovery of electronic conduction describe the ionic nature of electrical properties in the nematic phases of 4,4Ј-cyanopentylbiphenyl ͑5CB͒ and 4,4Ј-cyanooctylbiphenyl ͑8CB͒. 12,13 Furthermore, in a recent report that describes electronic conduction in phenylsubstituted quaterthiophene derivatives, it is emphasized that a large -conjugated core moiety of phenylquaterthiophene favors hopping conduction over ionic conduction due to an increase in the intermolecular transfer integral. 14 When a small molecule is ionized in its fluidic states such as nematic and isotropic phases in a given electric field, a charge transfer to a neighboring molecule and drift of the ionized molecule can be competitive.…”

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confidence: 97%

Electronic conduction in nematic phase of small molecules

et al. 2009

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We investigated charge-carrier transport in the nematic phase of small molecules such as 2-phenylbenzothiazoles by time-of-flight experiments, in which the conduction mechanism has been considered to be ionic. As a result, we established the hole and electron transports in the nematic phase of highly purified samples: we found that there were two transits, namely, fast and slow transits, in less pure samples; the slow transit was attributed to ionic conduction originating from trace amounts of impurities and the fast transit was attributed to electronic conduction whose attribution was elucidated by mobility changes in the diluted samples with a hydrocarbon of n-tetradecane ͑n-C 14 H 30 ͒. From these results, we conclude that the intrinsic conduction mechanism in the nematic phase of small molecules is ambipolar and electronic, irrespective of the size of the -conjugate system of the core moiety. Thus, they provide a new insight into the conduction mechanism in fluidic materials.

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confidence: 97%

Electronic conduction in nematic phase of small molecules

et al. 2009

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“…Because of the increased industrial production of display devices using nematic liquid crystals, a number of researchers have carried out detailed investigations on the electrical conductivity in nematic liquid crystals. [21][22][23] These liquid crystals were not so stable, and the contaminants or degraded species present in them caused ionic conduction. Ikeda et al synthesized nematic polymers having carbazolyl groups as pendants.…”

Section: -17mentioning

confidence: 99%

“…The mobility of ionic carriers is determined by the viscosity of the medium. 21 The viscosity of organic fluids decreases with an increase in the temperature, resulting in positive temperature dependence of the ionic mobility. In amorphous semiconductors, the carrier mobility increases with the electric field strength and temperature.…”

Section: Dependence Of Carrier Mobility In Meso-phases On the Field Ementioning

confidence: 99%

Development of Liquid-Crystalline Semiconductors with High Carrier Mobilities and Their Application to Thin-film Transistors

Funahashi

2009

Polym. J.

130

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Carrier transport in liquid-crystal phases, design of liquid-crystalline semiconductors with high carrier mobilities, and their application to field-effect transistors are reviewed. High carrier mobility has been observed in the smectic phases of oligothiophene derivatives as well as in the columnar phases of triphenylene and hexabenzocoronene derivatives. The mobility increases with the molecular ordering in the mesophases and extension of the -conjugated system of the liquidcrystal molecules. Asymmetrically substituted liquid-crystalline oligothiophene derivatives retain the highly ordered smectic phases below room temperature. The liquid crystals are solution-processable and can be used in high-performance field-effect transistors. The transistors exhibit high hole mobility and on/off ratio of 4 Â 10 À2 cm 2 V À1 s À1 and 10 7 , respectively.

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“…1) A quantitative investigation of mobile ions in LC materials is needed to clarify their relationship with the display quality; therefore, the mobility and number density of mobile ions determined by the analysis of ionic conduction have been discussed. [2][3][4][5] In general, the mobility of ions is influenced significantly by the viscosity of the matrix material. For many low-molecular-weight liquids, the Walden rule that the product of the mobility µ and viscosity η is a constant and independent of temperature is applicable.…”

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confidence: 99%