Topic
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.
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30 Sep 2011
TL;DR: In this paper, the in situ fabrication of complete field effect transistors by direct deposition of metal contacts and oxide gatedielectrics on the surface of free-standing pentacene single-crystals at room temperature (with the quasi-dynamic stencil deposition technique in pulsed laser deposition) is selected as main approach.
Abstract: Organic semiconductors are at the basis of Organic Electronics. Objective of this dissertation is “to fabricate high-quality organic molecular single-crystal devices”, to explore the intrinsic properties of organic semiconductors. To achieve this, the in situ fabrication of complete field-effect transistors by direct deposition of metal contacts and oxide gate
dielectrics on the surface of free-standing pentacene single-crystals at room temperature (with the ‘quasi-dynamic stencil deposition’ technique in pulsed laser deposition) is selected as main approach.
First, the structure of vapor-grown pentacene single-crystals is investigated. The observed morphology shows step flow is the dominant crystal growth mechanism. For pentacene, the most common oxidation product and largest impurity present is 6,13-pentacenequinone. It is observed that this quinone is preferentially located as a thin monolayer (partly) covering the crystal surface. In order to remove the quinones selectively, the partly-oxidized crystals are heated in vacuum at a fixed temperature overnight.
Next, the direct deposition of various materials through a stencil on the pentacene singlecrystal surface by PLD is investigated. By taking several precautions in the process, lowkinetic energy deposition or ‘soft-landing’ was achieved. Smooth and isolated patterns with a well-defined geometry were successfully deposited, without obvious destruction of the fragile substrate. The terraced structure of the underlying pentacene substrate is often still noticeable on top of the patterned features. A series of gold patterns is deposited on silicon oxide and pentacene single-crystals; the results show that the growth evolution of the surface roughness is similar on both kinds of substrates.
Finally, the influence of the deposition parameters applied in the device fabrication and performing a heat treatment on the electrical properties of pentacene single-crystals is investigated, by characterizing space-charge-limited current and field-effect transistor devices fabricated on the surface of pentacene single-crystals.
82 citations
TL;DR: In this paper, the authors investigated the dynamics of triplet excitons resulting from singlet fission in pentacene and their ionization at a C60 heterojunction.
Abstract: Singlet fission sensitized photovoltaics have the potential to surpass the Shockley-Queisser limit for a single-junction structure. We investigate the dynamics of triplet excitons resulting from singlet fission in pentacene and their ionization at a C60 heterojunction. We model the generation and diffusion of excitons to predict the spectral response. We find the triplet diffusion length in polycrystalline pentacene to be 40 nm. Poly(3-hexylthiophene) between the electrode and pentacene works both to confine triplet excitons and also to transfer photogenerated singlet excitons into pentacene with 30% efficiency. The lower bound for the singlet fission quantum efficiency in pentacene is 180 ± 15%.
81 citations
TL;DR: In this article, stable, solution-processed, small molecule polymer blend organic field effect transistors (OFETs) with a top-gate geometry were demonstrated on a flexible polyethersulfone (PES) substrate.
81 citations
TL;DR: In this article, degradation experiments on organic thin film transistors using the small organic molecule pentacene as the semiconducting material were conducted and the degradation was shown to have unambiguously degraded over 3 orders of magnitude in maximum on-current and charge carrier field effect mobility.
Abstract: This article reports degradation experiments on organic thin film transistors using the small organic molecule pentacene as the semiconducting material. Starting with degradation inert p-type silicon wafers as the substrate and SiO2 as the gate dielectric, we show the influence of temperature and exposure to ambient air on the charge carrier field-effect mobility, on-off-ratio, and threshold-voltage. The devices were found to have unambiguously degraded over 3 orders of magnitude in maximum on-current and charge carrier field-effect mobility, but they still operated after a period of 9 months in ambient air conditions. A thermal treatment was carried out in vacuum conditions and revealed a degradation of the charge carrier field-effect mobility, maximum on-current, and threshold voltage.
81 citations
TL;DR: In this paper, the authors show that ultrathinorganic gate dielectrics with high resultant capacitance possess good surface conditions (more hydrophobic and smoother surface) for the accommodation of an organic semi-conductor channel but are still problematic due to their struc-tural imperfections, including pinholes generated during deposition processes.
Abstract: and are not suitable for direct growth of an organicsemiconductor channel owing to their highly hydrophilic sur-faces, which are less compatible with the growth of organiccrystals, probably undergoing undesirable interface inter-actions with organic materials. On the other hand, ultrathinorganic gate dielectrics with high resultant capacitancepossess good surface conditions (more hydrophobic andsmoother surface) for the accommodation of an organic semi-conductor channel but are still problematic due to their struc-tural imperfections, including pinholes generated during de-position processes.
81 citations