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.

Ordered Structures of Tetracene and Pentacene on Cu(110) Surfaces

Abstract: The adsorption of tetracene on a Cu(110) surface has been studied with high-resolution energy loss spectroscopy, low-energy electron diffraction (LEED), and scanning tunneling microscopy (STM). Vibrational spectra confirm that at monolayer (ML) coverage the adsorbed molecules are in a flat-lying geometry with their molecular plane parallel to the substrate. At low coverage, 0.7 ML, LEED shows an oval pattern, which is related to a slightly disordered surface, while STM indicates molecules in different azimuthal orientations. At saturation coverage, a c(10 × 2) structure is formed, which gradually transfers into a p(5 × 2) structure on annealing at 340 K. STM reveals the molecular arrangement within both these unit cells and clearly indicates that the long molecular axis is aligned along 〈110〉. Molecular rows show a long-range wavelike behavior related to the interdigitation of C−H bonds of adjacent molecules. Similar structures, c(12 × 2) and p(6 × 2), are formed for pentacene on Cu(110).

High-Mobility Aligned Pentacene Films Grown by Zone-Casting

Abstract: We investigate the growth and field-effect transistor performance of aligned pentacene thin films deposited by zone-casting from a solution of unsubstituted pentacene molecules in a chlorinated solvent. Polarized optical microscopy shows that solution processed pentacene films grow as large crystalline domains with pronounced anisotropy in the substrate plane, in contrast to vacuum sublimed pentacene films, which consist of small crystalline grains with random in-plane orientation. The high structural alignment is confirmed by in-plane and out-of-plane X-ray diffraction analysis, with out-of-plane 00n reflections up to at least the seventh order, and a pronounced in-plane anisotropy with the a-axis of the triclinic unit cell predominantly aligned parallel to the zone-casting direction and the ab-plane parallel to the substrate. The average charge carrier mobility of the zone-cast pentacene devices depends strongly on the underlying dielectric. Divinylsiloxane-bis-benzocyclobutene (BCB) resin is found to b...

Hole-vibration coupling of the highest occupied state in pentacene thin films

Abstract: The hole-vibration coupling of the highest occupied state in pentacene thin films on graphite is studied by high-resolution ultraviolet photoelectron spectroscopy. Vibration satellites in the film show a take-off-angle dependence, indicating that the Franck-Condon principle is not strictly satisfied in this system. They are more intense than in the gas phase and the vibrational energy in the film is slightly lower than that in the gas phase. This demonstrates that the reorganization energy in pentacene thin films is slightly larger than that estimated from the photoelectron spectrum of free pentacene molecules. Furthermore, it is pointed out that the electron hopping in the low-temperature film may occur in the femtosecond scale before the electronic polarization of the surrounding medium is completed. © 2005 The American Physical Society.