Pentacene

About: Pentacene is a research topic. Over the lifetime, 5051 publications have been published within this topic receiving 161481 citations. The topic is also known as: 2,3:6,7-dibenzanthracene & benzo[b]naphthacene.

Band structure of the four pentacene polymorphs and effect on the hole mobility at low temperature.

Abstract: The band structure of the four known polymorphs of pentacene is computed from first principles using the accurate molecular orbitals of the isolated molecule as the basis for the calculation of the crystalline orbitals The computed bands are remarkably different for each polymorph, but their diversity can be easily rationalized using a simple analytical model that employs only three parameters The effect of the electronic structure on the hole mobility was evaluated using a simple model based on the constant relaxation time approximation It is found that the mobility tensor is highly anisotropic for three of the four considered polymorphs The practical implication of this prediction on the technology of thin-film organic transistors is discussed

Hysteresis of pentacene thin-film transistors and inverters with cross-linked poly(4-vinylphenol) gate dielectrics

Abstract: The authors report the effects of hydroxyl groups (OH bonds) on the electrical reliabilities of pentacene organic thin-film transistors (OTFTs) with poly-4-vinylphenol (PVP) gate dielectrics. PVP gate dielectric films mixed with different concentrations of methylated poly(melamine-co-formaldehyde) (MMF) were fabricated, and experiments on the hysteresis behavior of the OTFT device were conducted. Pentacene TFTs with the PVP (MMF 0wt.%) exhibited a large hysteresis, while in the PVP (MMF 125wt.%), nearly no hysteresis was observed. Large hysteresis observed in OTFT devices was confirmed to be strongly related to the hydroxyl groups existing inside of the polymeric dielectrics and could reduced by the decrease of OH group.

Effects of polarized organosilane self-assembled monolayers on organic single-crystal field-effect transistors

Abstract: The surface conductivity is measured by a four-probe technique for pentacene and rubrene single crystals laminated on polarized and nearly unpolarized molecular monolayers with application of perpendicular electric fields. The polarization of the self-assembled monolayers (SAMs) shifts the threshold gate voltage, while maintaining a very low subthreshold swing of the single-crystal devices (0.11 V∕decade). The results, excluding influences of parasitic contacts and grain boundaries, demonstrate SAM-induced nanoscale charge injection up to ∼1012cm−2 at the surface of the organic single crystals.

Charge Trapping in Intergrain Regions of Pentacene Thin Film Transistors

Abstract: A scanning Kelvin probe microscopy (SKPM) study of the surface potential of vacuum sublimed pentacene transistors under bias stress and its correlation with the film morphology is presented. While for thicker films there are some trapping centers inhomogeneously distributed over the film, as previously reported by other authors, by decreasing the film thickness the effect of thin intergrain regions (IGRs) becomes clear and a very good correlation between the topography and the potential data is observed. It is shown that in the thick pentacene grains the potential is homogeneous and independent of the gate bias applied with negligible charge trapping, while in the thin IGRs the potential varies with the applied gate bias, indicating that only an incomplete accumulation layer can be formed. Clear evidence for preferential charge trapping in the thin IGRs is obtained.

Nanoscale organic transistors that use source/drain electrodes supported by high resolution rubber stamps

Abstract: Soft contact lamination and metal-coated elastomeric stamps provide the basis for a convenient and noninvasive approach to establishing high resolution electrical contacts to electroactive organic materials. The features of relief on the stamps define, with nanometer resolution, the geometry and separation of electrically independent electrodes that are formed by uniform, blanket evaporation of a thin metal film onto the stamp. Placing this coated stamp on a flat substrate leads to “wetting” and atomic scale contact that establishes efficient electrical connections. When the substrate supports an organic semiconductor, a gate dielectric and a gate, this soft lamination process yields high performance top contact transistors with source/drain electrodes on the stamp. We use this approach to investigate charge transport through pentacene in transistor structures with channel lengths that span more than three decades: from 250 μm to ∼150 nm. We also report some preliminary measurements on charge transport through organic monolayers using the same laminated transistor structures.