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.

Cyanation: Providing a Three‐in‐One Advantage for the Design of n‐Type Organic Field‐Effect Transistors

Abstract: The theoretical work presented here demonstrates that, when substitution takes place at appropriate positions, cyanation could be a useful tool for reducing the internal reorganization energy of molecules. A molecular-orbital-based explanation is given for this fundamentally important phenomenon. Some of the cyanated pentacene derivatives (nCN-PENT-n) not only have internal reorganization energies for electron transfer (lambda(-)) smaller than that of pentacene, but the lambda(-) values are even of the same magnitude as the internal reorganization energy for hole transfer (lambda(+)) of pentacene, a small value that few organic compounds have surpassed. In addition, cyanation raises the electron affinity of the parent compound and may afford good electronic couplings between neighboring molecules, because of its ability in promoting pi-stacking. For the design of high performance n-Type Organic field-effect transistors, high electron affinities, large intermolecular electronic couplings, and small reorganization energies are necessary. Cyanation may help in all three aspects. Two cyanated trialkylsilylethynyl pentacene derivatives with known pi-stacking structures are predicted to provide reasonably small internal reorganization energies, large electronic couplings, and high electron affinities. They have the potential to outperform N-fluoroalkylated dicyanoperylene-3,4:9,10-bis(dicarboximides) (PDI-FCN(2)) in terms of electron mobility.

Fully patterned all-organic thin film transistors

Abstract: We have fabricated fully patterned all-organic thin film transistors on glass substrates using the conducting polymer poly(3,4-ethylenedioxythiophene) for the gate electrodes and the source and drain contacts, poly-4-vinylphenol for the gate dielectric layer, and pentacene or poly-3-hexylthiophene for the organic active layer. All-organic pentacene transistors have carrier mobility as large as 0.1 cm2/V s and threshold voltage of 1 V, similar to pentacene transistors fabricated with high-quality inorganic gate dielectrics and noble-metal contacts. The carrier mobility of all-polymer poly-3-hexylthiophene transistors is somewhat lower compared with that of pentacene transistors, but similar to that of poly-3-hexylthiophene devices made with inorganic metals and dielectrics.

Highly sensitive thin-film organic phototransistors: Effect of wavelength of light source on device performance

Abstract: Organic phototransistors (OPTs) were fabricated from pentacene and copper phthalocyanine (CuPC) based on the geometry of organic field-effect transistors (OFETs); and the effect of the wavelength of the incident light source on their performance was examined High performance OFETs with pentacene and CuPC were fabricated and the characteristics of the OPTs were examined under UV and visible-light irradiations with top illumination The CuPC and pentacene OPTs show a high responsivities of 05–2 and 10–50A∕W and maximum IPh∕IDark of 3000 and 13×105, respectively, under 365nm UV light However, under visible light, at a wavelength of 650nm, the pentacene OPTs had 100 times less responsivity, 015–045A∕W, and a IPh∕IDark of 1000, even though an absorption coefficient three times larger was observed at this wavelength than at 365nm A strong correlation was found between the performance of the OPTs and the incident photon to current conversion efficiency spectra of an organic semiconductor The strong depen

Low‐Voltage Organic Thin‐Film Transistors with High‐k Nanocomposite Gate Dielectrics for Flexible Electronics and Optothermal Sensors

Abstract: The performance of organic thin-film transistors (OTFT) for flexible, low cost and disposable “plastic” electronic products advances rapidly: various organic semiconductors display hole or electron carrier mobilities that compare favorably with those of hydrogenated amorphous silicon, the inorganic counterpart for such applications as flexible displays, smart cards and radio frequency identification tags, nonvolatile memories and sensors The possibility for tailoring functional organic materials, bears potential towards novel electronic products such as smart skins, smart textiles and “invisible electronics”, where multiple functionalities, portability and ubiquitous integration is requested In this context diverse properties of organic thin-film devices are inevitable such as lightweight, low power consumption, low operationvoltage and compatibility with diverse substrates Reducing the threshold voltage and the subthreshold swing is essential for operating OTFTs at low-voltage levels When combined with very low gate leakage currents, OTFTs may also become a key element in high-end sensor applications, such as flexible touch pads and screens or thermal imaging tools for night vision, surveillance or for the detection of undesired heat loss paths in buildings The aforementioned transistor parameters not only critically depend on the thickness and the dielectric properties of the gate insulator, but also on the trapped charge densities at the interface between these materials The selection of semiconductors and gate insulators with excellent interface properties is currently the challenge in the quest for improving the performance of OTFTs Here we show that bottom-gate OTFTs based on the organic semiconductor pentacene and high-k nanocomposite gate dielectrics, exhibit transistor performances with very low gate leakage currents, subthreshold swings close to the theoretical limit, and low-voltage battery operation The subthreshold swings of OTFTs with different organic and hybrid gate dielectrics follow an inverse dependence on the gate capacitance as is expected by standard MOS theory The trapped charge carrier density at the interface between the semiconductor and the dielectric surpasses that of the SiO2-pentacene interface, being close to the average trap densities in the SiO2–Si interface in metal oxide semiconductor transistors [15] We also report the first application of these OTFTs in an optothermal light sensor We describe the transistor, the temperature sensitive fluorinated polymer, their combination in an integrated circuit, and the application of this circuit as a thermal infrared sensor and as a switch that can be operated by a laser pointer Figure 1 shows the structure of low-voltage organic transistors with high dielectric constant (high-k) oxide–polymer nanocomposites Al2O3 or ZrO2 were chosen as high-k dielectric materials, combined with poly(a-methyl styrene) (PaMS) or poly(vinyl cinnamate) (PVCi) to form a smooth and dense nanocomposite gate dielectric Pentacene is used as the organic semiconductor material, the gate electrode is based on Al, while Au source and drain electrodes are employed Figure 1b, c, and d show atomic force microscopy (AFM) images of a ZrO2/PaMS nanocomposite gate dielectric based transistor The bare ZrO2 metal oxide surface is displayed in Figure 1b, the nanocomposite in (c) and the pentacene layer grown on top of the nanocomposite dielectric in (d) The AFM images clearly reveal that the rough (surface rms-roughness = 15 nm) and less dense ZrO2 layer, which is composed of regularly clubbed grains (Fig 1a), smoothens by forming the nanocomposite (rms-roughness = 04 nm) The substrate roughness critically influences the growth dynamics of pentacene molecules on top of dielectric surfaces, grain sizes typically increase with decreasing surface roughness For rmsroughness values below 05 nm the pentacene morphology is characterized by dentritic crystallites of several microns C O M M U N IC A IO N