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.

Hole mobility enhancement of pentacene organic field-effect transistors using 4,4′,4″-tris[3-methylphenyl(phenyl)amino] triphenylamine as a hole injection interlayer

Abstract: Organic field-effect transistors(OFETs) were prepared and analyzed by inserting various thickness of 4,4′,4″-tris[3-methylphenyl(phenyl)amino] triphenylamine (m-MTDATA) between pentacene and goldelectrodes as a hole injection layer. These OFETs showed a significant enhancement of hole mobility comparing to the corresponding single layer device. The interfacial morphologies of pentacene and pentacene/m-MTDATA contact were characterized by atomic force microscopy. The hole mobility improvement of OFETs was attributed to an intermediate energy level formed between pentacene and gold heterojunction when inserting an ultrathin m-MTDATA layer, leading to a remarkable reduction of contact resistance at the metal-organic interface.

Monolayer and bilayer pentacene on Cu(111)

Abstract: The morphology and electronic structure of pentacene (Pn) deposited on Cu(111) was studied using scanning tunneling microscopy (STM) and spectroscopy (STS). Deposition of a multilayer followed by annealing to reduce coverage to a monolayer results in the formation of either of two unique phases: a two-dimensional herringbone structure previously unobserved for any linear acene to our knowledge, or a “random-tiling” structure. Coverage greater than a monolayer promotes the formation of a bilayer phase similar to that observed for Pn/Ag(111). STS shows that the electronic structure of the first layer is strongly modified due to its proximity to the substrate, while the second layer exhibits nearly bulklike electronic structure.

Organic thin film transistors using 6,13-bis(tri-isopropylsilylethynyl) pentacene embedded into polymer binders

Abstract: The active channel material of an organic thin film transistor (OTFT), 6,13-bis(tri-isopropylsilylethynyl)pentacene (TIPS pentacene), is a functionalized pentacene designed to enhance both the solubility and solid-state packing of the pentacene. In this work, in order to improve device performance, three types of polymer binders—poly(α-methylstyrene) (PAMS), poly(4-vinylbiphenyl) (PVBP), and poly(triarylamine) (PTAA)—were employed to fabricate OTFT devices with organic soluble TIPS pentacene. These binders improved film formation in a large area uniformly and helped the TIPS pentacene to form a stronger binding between source/drain electrodes onto dielectric layer. Thus, device performance was highly improved due to improvement of interfacial contact and an increase in the charge transfer in the active channel. OTFTs using TIPS pentacene with PAMS, PVBP, and PTAA for field effect mobilities in the saturation regime have 5×10−3, 8×10−3, and 2.7×10−2 cm2/V s, respectively.

Comment on "Single pentacene molecules detected by fluorescence excitation in a p-terphenyl crystal"

Abstract: : Using highly efficient Fluorescence excitation spectroscopy of individual pentacene molecular impurities in p-terphenyl crystals, we have observed that some pentacene defects exhibit spontaneous spectral jumps in their resonance frequency at 1.5 K, with a jump rate independent of laser power. In addition, the low-power limiting linewidth for single pentacene absorbers reaches the lifetime limit of 7.8 MHz at 1.5 K.

Effect of molecule-substrate interaction on thin-film structures and molecular orientation of pentacene on silver and gold.

Abstract: Evaporated pentacene thin films with thicknesses from several nm to 150 nm on gold and silver substrates have been studied by ultraviolet photoelectron spectroscopy (UPS), near-edge X-ray absorption fine structure (NEXAFS), scanning tunneling microscopy (STM), and atomic force microscopy (AFM). It was found that pentacene thin-film structures, particularly their molecular orientations, are strongly influenced by the metal substrates. UPS measurements revealed a distinct change in the valence band structures of pentacene on Au compared to those on Ag, which is attributed to the different packing between adjacent molecules. Using NEXAFS, we observed 74 ± 5° and 46 ± 5° molecular tilt angles on Ag and Au, respectively, for all measured thicknesses. We propose that pentacene molecules stand up on the surface and form the “thin-film phase” structure on Ag. On Au, pentacene films grow in domains with molecules either lying flat or standing up on the substrate. Such a mixture of two crystalline phases leads to an average tilt angle of 46° for the whole film and the change in valence band structures. STM and distance−voltage (z−V) spectroscopy studies confirm the existence of two crystalline phases on Au with different conducting properties. z−V spectra on the low conducting phase clearly indicate its nature as “thin-film phase”.