Photoconductivity in the columnar phases of a glassy discotic twin

Adam, Dieter; Schuhmacher, Peter; Simmerer, J.; Häußling, Lukas; Paulus, Wolfgang; Siemensmeyer, K.; Etzbach, Karl-Heinz; Ringsdorf, Helmut; Haarer, D.

doi:10.1002/adma.19950070305

Cited by 88 publications

(45 citation statements)

References 28 publications

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“…1.͒ Of particular relevance to their possible use in electronic device applications are charge carrier mobility measurements. Experimental mobility values have been obtained from time-of-flight ͑TOF͒ measurements, [5][6][7][8][9][10][11][12][13] pulseradiolysis time-resolved microwave conductivity ͑PR-TRMC͒ measurements 14 -20 and frequency dependent AC conductivity measurements on doped samples. [21][22][23][24] The conductivity in triphenylene derivatives is mainly due to transport of positive charges ͑holes͒ and for the liquid crystalline phase mobility values in the range 10 Ϫ3 -10 Ϫ1 cm 2 V Ϫ1 s…”

Section: Introductionmentioning

confidence: 99%

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Senthilkumar

Grozema

Bickelhaupt

et al. 2003

The Journal of Chemical Physics

410

417

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Values of charge transfer integrals, spatial overlap integrals and site energies involved in transport of positive charges along columnar stacked triphenylene derivatives are provided. These parameters were calculated directly as the matrix elements of the Kohn-Sham Hamiltonian, defined in terms of the molecular orbitals on individual triphenylene molecules. This was realized by exploiting the unique feature of the Amsterdam density functional theory program that allows one to use molecular orbitals on individual molecules as a basis set in calculations on a system composed of two or more molecules. The charge transfer integrals obtained in this way differ significantly from values estimated from the energy splitting between the highest occupied molecular orbitals in a dimer. The difference is due to the nonzero spatial overlap between the molecular orbitals on adjacent molecules. Calculations were performed on unsubstituted and methoxy-or methylthio-substituted triphenylenes. Charge transfer integrals and site energies were computed as a function of the twist angle, stacking distance and lateral slide distance between adjacent molecules. The variation of the charge transfer integrals and site energies with these conformational degrees of freedom provide a qualitative explanation of the similarities and differences between the experimental charge carrier mobilities in different phases of alkoxy-and alkylthio-substituted triphenylenes. The data obtained from the present work can be used as input in quantitative studies of charge transport in columnar stacked triphenylene derivatives.

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Section: Introductionmentioning

confidence: 99%

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Senthilkumar

Grozema

Bickelhaupt

et al. 2003

The Journal of Chemical Physics

410

417

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“…In fact, a complicated dependence of the hole mobility on the temperature was also reported for a columnar phase consisting of a triphenylene dimer [27]. In this case, the hole mobility exhibits a maximum value as a result of an imperfect balance between the two effects.…”

Section: Characteristics Ofthe Field-effect Transistors Using 3-mentioning

confidence: 90%

Temperature-Independent Hole Mobility in Field-Effect Transistors Based on Liquid-Crystalline Semiconductors

Funahashi

Zhang

Tamaoki

2011

IEICE Trans. Electron.

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SUMMARY Thin-film transistors based on Liquid-crystalline phenylterthiophenes, 3-TTPPh-5 and 3-TTPPhF4-6 are fabricated with a spincoating method. The devices exhibit p-type operation with the mobility on the order of 10-2 cm 2 V-1 s-l. The field-effect mobilities of the transistors using 3-TTPPh-5 and 3-TTPPhF4-6 are almost independent of the temperature above room temperatnre. In particular, the temperature range in which the mobility is constant is between 230 and 350 K for 3-TIPPh-5.

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“…The hole transport characteristics in the columnar phases of the triphenylene dimer 2, as shown in Figure 5, are studied over a wide temperature range. 56,57 Above 0 C, the hole mobility is almost independent of the electric field and the temperature; in contrast, below 0 C, it increases with the electric field strength and temperature. The dependence of the hole mobility on electric field strength becomes more pronounced at low temperatures.…”

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

confidence: 99%

“…The dependence of the hole mobility on electric field strength becomes more pronounced at low temperatures. 56,57 This behavior is described by the onedimensional Gaussian disorder model (GDM), which was proposed for the carrier transport in amorphous organic semiconductors. 58 A similar behavior was observed in the columnar phase of a hexabenzocoronene derivative.…”

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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Photoconductivity in the columnar phases of a glassy discotic twin

Cited by 88 publications

References 28 publications

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on charge transfer integrals and site energies

Temperature-Independent Hole Mobility in Field-Effect Transistors Based on Liquid-Crystalline Semiconductors

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

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