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Mobility Anisotropy (mobility + anisotropy)

Distribution by Scientific Domains

Polymers and Materials Science	75%

Selected Abstracts

Probing the Anisotropic Field-Effect Mobility of Solution-Deposited Dicyclohexyl-,-quaterthiophene Single Crystals,

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2007

Abstract Measuring the anisotropy of the field-effect mobility provides insight into the correlation between molecular packing and charge transport in organic semiconductor materials. Single-crystal field-effect transistors are ideal tools to study intrinsic charge transport because of their high crystalline order and chemical purity. The anisotropy of the field effect mobility in organic single crystals has previously been studied by lamination of macroscopically large single crystals onto device substrates. Here, a technique is presented that allows probing of the mobility anisotropy even though only small crystals are available. Crystals of a soluble oligothiophene derivative are grown in bromobenzene and drop-cast onto substrates containing arrays of bottom-contact gold electrodes. Mobility anisotropy curves are recorded by measuring numerous single crystal transistor devices. Surprisingly, two mobility maxima occur at azimuths corresponding to both axes of the rectangular cyclohexyl-substituted quaterthiophene (CH4T) in-plane unit cell, in contrast to the expected tensorial behavior of the field effect mobility. [source]

High-Performance Organic Single-Crystal Transistors and Digital Inverters of an Anthracene Derivative

ADVANCED MATERIALS, Issue 36 2009
Lang Jiang
Single-crystal disks of di(phenylvinyl) anthracene, micro- or nanometer-sized and flexible, are produced by physical vapor transport. Subsequently, single- crystal transistors are fabricated by the organic ribbon mask method and integrated to produce high-performance inverters. The mobility of the transistors, the mobility anisotropy along different crystal axes of the disks, and the maximum gain of the inverters are reported. [source]

Solution-Grown, Macroscopic Organic Single Crystals Exhibiting Three-Dimensional Anisotropic Charge-Transport Properties

ADVANCED MATERIALS, Issue 18 2009
Beatrice Fraboni
Macroscopic single crystals of 4-hydroxy-cyanobenzene (4HCB) grown from solution exhibit reproducible and marked 3D mobility anisotropy. Air-gap OFET measurements along the planar axes a and b deliver average mobilities of 3,×,10,2 and 6,×,10,3,cm2 V,1 s,1, respectively. Space-charge-limited current (SCLC) experiments reveal an average mobility along the c axis of 4,×,10,6,cm2,V,1,s,1. [source]

Intrachain versus Interchain Electron Transport in Poly(fluorene- alt -benzothiadiazole): A Quantum-Chemical Insight

CHEMPHYSCHEM, Issue 7 2008
Antoine Van Vooren
Abstract Poly(9,9-di- n -octylfluorene- alt -benzothiadiazole) [F8BT], displays very different charge-transport properties for holes versus electrons when comparing annealed and pristine thin films and transport parallel (intrachain) and perpendicular (interchain) to the polymer axes. The present theoretical contribution focuses on the electron-transport properties of F8BT chains and compares the efficiency of intrachain versus interchain transport in the hopping regime. The theoretical results rationalize significantly lowered electron mobility in annealed F8BT thin films and the smaller mobility anisotropy (,,/,,) measured for electrons in aligned films (i.e. 5,7 compared to 10,15 for holes). [source]