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.

Flexible low-voltage organic transistors and circuits based on a high-mobility organic semiconductor with good air stability.

Abstract: Flexible transistors and circuits based on dinaphtho-[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT), a conjugated semiconductor with a large ionization potential (5.4 eV), are reported. The transistors have a mobility of 0.6 cm(2) V-1 s(-1) and the ring oscillators have a stage delay of 18 mu s. Due to the excellent stability of the semiconductor, the devices and circuits maintain 50% of their initial performance for a period of 8 months in ambient air.

Organic thin-film transistors with nanocomposite dielectric gate insulator

Abstract: High-performance organic thin-film transistors (OTFTs) with a nanoparticle composite dielectric layer have been demonstrated. The dielectric layer consists of cross-linked poly-4-vinylphenol (PVP) and high-dielectric titanium dioxide (TiO2) nanoparticles. Because of the nanosize of TiO2, it disperses well in the organic solvent, which makes it possible to use solution-processable methods to prepare the dielectric layer. OTFTs with pentacene as the semiconducting layers have been demonstrated; it was found that the OTFTs with the nanocomposite dielectric layer have higher field-induced current than that of conventional devices because the dielectric constant of the gate insulator is increased. This finding opens an interesting direction for the preparation of high-performance OTFTs without complicated sputtering of high-κ dielectric materials.

Ambipolar pentacene field-effect transistors with calcium source-drain electrodes

Abstract: Field-effect transistors consisted of vacuum-sublimed polycrystalline pentacene films and calcium source-drain electrodes were prepared and device characteristics were evaluated in an oxygen-free condition. The field-effect transistor showed typical ambipolar characteristics and field-effect hole mobility of 4.5×10−4cm2/Vs and field-effect electron mobility of 2.7×10−5cm2∕Vs were estimated from saturation currents. Appearance of an electron enhancement mode in pentacene field-effect transistors was ascribed to the lowering of barrier for electron injection at source-drain electrodes. Effective elimination of electron traps using an oxygen-free condition was found to be another requirement for the observation of ambipolar behavior in pentacene.

Nucleation of organic semiconductors on inert substrates

Abstract: We have adapted the microscopic theory of nucleation for the epitaxial growth of inorganic materials to the nucleation of organic small molecules on an inert substrate like the gate dielectric of an organic thin-film transistor. The parameters required to explore the model were calculated with the standard MM3 force field and also include experimentally determined vapor pressure data, as well as film growth data. Sufficient agreement is found between the experimentally determined equilibrium crystal shape and heats of sublimation on the one hand and the calculated parameters on the other hand. The growth of pentacene, tetracene, and perylene on inert substrates has been studied in terms of this theory, especially focusing on the two-dimensional (2D) to 3D nucleation transition. It is demonstrated that 3D nucleation leads to ill-connected grains, while 2D nucleated grains form continuous films suitable for charge transport. The analysis of this transition allows for the experimental determination of the molecule-substrate interactions for a given molecule on a given surface. It was found that the deposition conditions for 2D growth shift to less favorable substrate temperatures and deposition rates as the difference between interlayer interactions and molecule-substrate interactions increase and the intralayer interactions decrease. Moreover, those interactions affect the nucleation rate and therefore the ultimate 2D grain size that can be obtained.

Cross-Linked Polymer Gate Dielectric Films for Low-Voltage Organic Transistors

Abstract: Cross-linked polymer films were investigated as new gate dielectric materials for low-voltage thin-film transistors. Poly(4-vinylphenol) (PVP) was cross-linked through esterification reactions with commercially available bifunctional anhydrides, acyl chlorides, and carboxylic acids. The polymer dielectric films were evaluated based on surface morphology, capacitance, leakage current, and their compatibility with organic semiconductors. Thin insulating PVP films cross-linked with dianhydrides yielded a capacitance as high as 400 nF/cm2 with leakage currents below 10−8 A/cm2. Organic thin-film transistors (OTFTs) fabricated on these gate dielectric layers exhibited charge carrier mobilities as high as 3 cm2/(V s) for p-channel pentacene on octadecyltriethoxylsilane (OTS)-modified PVP and 0.045 cm2/(V s) for n-channel perfluorinated copper phthalocyanine (FCuPc).