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.

Thermal transport properties of thin films of small molecule organic semiconductors

Abstract: A series of harmonic Joule-heating experiments have been employed to determine the thermal conductivities of thin films of pentacene, N,N′-diphenyl−N,N′-di(3-methylphenyl)−(1,1′-biphenyl)-4,4′-diamine, and tris(8-hydroquinolinato)aluminum, three widely used organic semiconductors Room-temperature thermal conductivity values of 051, 024, and 048W∕mK were measured for films of these three compounds, respectively These values are over two orders of magnitude lower than those of inorganic semiconductors While amorphous films were found to display only small thermal conductivity changes over the temperature range of 228–350 K, pentacene exhibited stronger variations that are typical of phonon-phonon scattering observed in polycrystalline semiconductors

Study of organic thin film transistor with polymethylmethacrylate as a dielectric layer

Abstract: The properties of pentacene-based organic thin film transistors (OTFTs) with polymethylmetha-crylate (PMMA) as a dielectric layer have been investigated. The concentration of PMMA was about 8wt% with toluene as solvent. The pentacene film on PMMA dielectric layer displays high thin film quality according to results of x-ray diffraction scan and atomic force microscopy. The crystalline size was about 33.96nm and the grain size was about 1000–1500nm. The pentacene-based OTFTs with PMMA as a dielectric layer exhibited excellent electric characteristics, including a high mobility of 0.241cm2∕Vs or larger, an on/off current ratio of 104 or larger, and the threshold voltage of less than −6.3V.

Bio-Organic Optoelectronic Devices Using DNA

Abstract: Biomolecular DNA, as a marine waste product from salmon processing, has been exploited as biodegradable polymeric material for photonics and electronics. For preparing high optical quality thin films of DNA, a method using DNA with cationic surfactants such as DNA–cetyltrimethylammonium, CTMA has been applied. This process enhances solubility and processing for thin film fabrication. These DNA–CTMA complexes resulted in the formation of self-assembled supramolecular films. Additionally, the molecular weight can be tailored to suit the application through sonication. It revealed that DNA–CTMA complexes were thermostable up to 230∘ C. UV–VIS absorption shows that these thin films have high transparency from 350 to about 1,700 nm. Due to its nature of large band gap and large dielectric constant, thin films of DNA–CTMA has been successfully used in multiple applications such as organic light emitting diodes (OLED), a cladding and host material in nonlinear optical devices, and organic field-effect transistors (OFET). Using this DNA based biopolymers as a gate dielectric layer, OFET devices were fabricated that exhibits current–voltage characteristics with low voltages as compared with using other polymer-based dielectrics. Using a thin film of DNA–CTMA based biopolymer as the gate insulator and pentacene as the organic semiconductor, we have demonstrated a bio-organic FET or BioFET in which the current was modulated over three orders of magnitude using gate voltages less than 10 V. Given the possibility to functionalise the DNA film customised for specific purposes viz. biosensing, DNA–CTMA with its unique structural, optical and electronic properties results in many applications that are extremely interesting.

Thin bismuth film as a template for pentacene growth

Abstract: Thin Bi(001) films grown by ultrahigh vacuum deposition on Si(111)‐7×7 surfaces at room temperature, were annealed at ∼400K in order to improve their morphology by reducing the step density on the surface. Annealed, well-ordered Bi(001) films have been subsequently used as substrates for growth of pentacene (Pn). It has been determined using low-energy electron microscope that Pn nucleates on Bi(001) into a highly ordered, crystalline layer, with Pn molecules “standing up” on the Bi surface, and the (001) plane on the growth front. Moreover, the Pn layer is aligned with the Bi(001) surface having a “point-on-line” commensurate relationship with the substrate. The Pn∕Bi(001) film crystallizes in a bulk-like structure directly from the first Pn layer. Formation of the thin film phase reported for the Pn growth on SiO2 and other inert substrates was not observed in our experiments.

Selective Observation of Outermost Surface Layer during Epitaxial Growth by Penning-Ionization Electron Spectroscopy: Pentacene on Graphite

Abstract: By means of Penning-ionization electron spectroscopy the outermost surface layer of a pentacene film on a graphite substrate (cleavage plane) was selectively observed. Ultraviolet photoelectron spectroscopy was also applied to observe several layers from the surface. From the analyses of the two types of spectra the subtle changes in the electronic state and the molecular orientation of the outermost layer and also those of inner layers were probed separately during the layer-by-layer epitaxial growth of the film.