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.

High-mobility polymer gate dielectric pentacene thin film transistors

Abstract: We have fabricated pentacene organic thin film transistors with spin-coated polymer gate dielectric layers, including cross-linked polyvinylphenol and a polyvinylphenol-based copolymer, and obtained devices with excellent electrical characteristics, including carrier mobility as large as 3 cm2/V s, subthreshold swing as low as 1.2 V/decade, and on/off current ratio of 105. For comparison, we have also fabricated pentacene transistors using thermally grown silicon dioxide as the gate dielectric and obtained carrier mobilities as large as 1 cm2/V s and subthreshold swing as low as 0.5 V/decade.

Functionalized Pentacene: Improved Electronic Properties from Control of Solid-State Order

Abstract: Molecular order has proven to be a significant factor in the performance of devices based on organic semiconductors. Recent studies involving solubilized versus unsubstituted thiophene oligomers have demonstrated that modifications which increase orbital overlap in the solid state can improve device performance by more than an order of magnitude. 1 Similar studies on pentacene, a compound which has already demonstrated remarkable potential for device applications, 2 have also focused on maximizing orbital overlap by inducing order in films. 3 However, these pentacene studies have thus far relied on substrate modification, rather than on pentacene functionalization, 4 to achieve the desired goals. We report here the preparation of two functionalized pentacene derivatives, and the effect of this functionalization on both the solid-state ordering and the electronic properties of the resulting crystals. Our goal for a functionalized pentacene was two-fold: First, the substituents should impart solubility to the acene, to simplify purification and processing. Second, the substituents should induce some capability for self-assembly of the aromatic moieties into ﷿-stacked arrays to enhance intermolecular orbital overlap. We anticipated that both of these goals could be accomplished by exploiting a rigid spacer to hold the necessarily bulky solubilizing groups well away from the aromatic core, allowing the closest possible contact between the aromatic rings. 5 Our initial targets were the bis(triisopropylsilylethynyl)pentacenes 1 and 2. Both of these compounds are easily prepared in near quantitative yield in a one-pot reaction from 6,13-pentacenequinone and 5,14pentacenequinone, respectively. 6

Tuning charge transport in solution-sheared organic semiconductors using lattice strain

Abstract: A solution-processing method known as solution shearing is used to introduce lattice strain to organic semiconductors, thus improving charge carrier mobility. Solution-processed organic semiconductors show great promise for application in cheap and flexible electronic devices, but generally suffer from greatly reduced electronic performance — most notably charge-carrier mobilities — compared with their inorganic counterparts. Borrowing a trick from the inorganic semiconductor community, Giri et al. show how the introduction of strain into an organic semiconductor, through a simple solution-processing technique, modifies the molecular packing within the material and hence its electronic performance. For one material studied, the preparation of a strained structure is shown to more than double the charge-carrier mobility. Circuits based on organic semiconductors are being actively explored for flexible, transparent and low-cost electronic applications1,2,3,4,5. But to realize such applications, the charge carrier mobilities of solution-processed organic semiconductors must be improved. For inorganic semiconductors, a general method of increasing charge carrier mobility is to introduce strain within the crystal lattice6. Here we describe a solution-processing technique for organic semiconductors in which lattice strain is used to increase charge carrier mobilities by introducing greater electron orbital overlap between the component molecules. For organic semiconductors, the spacing between cofacially stacked, conjugated backbones (the π–π stacking distance) greatly influences electron orbital overlap and therefore mobility7. Using our method to incrementally introduce lattice strain, we alter the π–π stacking distance of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) from 3.33 A to 3.08 A. We believe that 3.08 A is the shortest π–π stacking distance that has been achieved in an organic semiconductor crystal lattice (although a π–π distance of 3.04 A has been achieved through intramolecular bonding8,9,10). The positive charge carrier (hole) mobility in TIPS-pentacene transistors increased from 0.8 cm2 V−1 s−1 for unstrained films to a high mobility of 4.6 cm2 V−1 s−1 for a strained film. Using solution processing to modify molecular packing through lattice strain should aid the development of high-performance, low-cost organic semiconducting devices.

Stacked pentacene layer organic thin-film transistors with improved characteristics

Abstract: Using two layers of pentacene deposited at different substrate temperatures as the active material, we have fabricated photolithographically defined organic thin-film transistors (OTFTs) with improved field-effect mobility and subthreshold slope. These devices use photolithographically defined gold source and drain electrodes and octadecyltrichlorosilane-treated silicon dioxide gate dielectric. The devices have field-effect mobility as large as 1.5 cm/sup 2//V-s, on/off current ratio larger than 10/sup 8/, near zero threshold voltage, and subthreshold slope less than 1.6 V per decade. To our knowledge, this is the largest field-effect mobility and smallest subthreshold slope yet reported for any organic transistor, and the first time both of these important characteristics have been obtained for a single device.

Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

Abstract: Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach—termed fluid-enhanced crystal engineering (FLUENCE)—that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V−1 s−1 and 11 cm2 V−1 s−1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics. Solution printing of organic semiconductors could in principle be scaled to industrial needs, yet attaining aligned single-crystals directly with this method has been challenging. By using a micropillar-patterned printing blade designed to enhance the control of crystal nucleation and growth, thin films of macroscopic, highly aligned single crystals of organic semiconductors can now be fabricated.