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Organic semiconductor
About: Organic semiconductor is a research topic. Over the lifetime, 15905 publications have been published within this topic receiving 533881 citations.
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TL;DR: In this article, the performance of p-and n-type conducting polymer and small molecule organic semiconductors are reviewed primarily in terms of field effect mobility, current on/off ratio, and operating voltage for various OTFT structures.
Abstract: Organic thin film transistor (OTFT) based device modeling and circuit application is a rapidly emerging research area. Taking cognizance of this fact, our paper reviews various basic to advanced OTFT structures, their performance parameters, materials of individual OTFT layers, their molecular structures, OTFT charge transport phenomena, and fabrication techniques. The performance of p- and n-type conducting polymer and small molecule organic semiconductors are reviewed primarily in terms of field effect mobility, current on/off ratio, and operating voltage for various OTFT structures. Moreover, different organic/inorganic materials for realizing the dielectric layer, electrodes, and the substrate in an OTFT are analyzed. Some of the compact models that are essential for predicting and optimizing the device performance are described that takes into account the mobility enhancement factor and channel length modulation. A detailed study of the single gate, dual gate, vertical channel, and cylindrical gate O...
268 citations
TL;DR: This Account reviews key experimental findings from TR-2PPE experiments and presents a theoretical analysis of the quantum coherent mechanism based on electronic structural and density matrix calculations for crystalline tetracene lattices, which reveals the critical roles of the charge transfer states and the high dephasing rates in ensuring the ultrafast formation of multiexciton states.
Abstract: The absorption of one photon by a semiconductor material usually creates one electron–hole pair. However, this general rule breaks down in a few organic semiconductors, such as pentacene and tetracene, where one photon absorption may result in two electron–hole pairs. This process, where a singlet exciton transforms to two triplet excitons, can have quantum yields as high as 200%. Singlet fission may be useful to solar cell technologies to increase the power conversion efficiency beyond the so-called Shockley-Queisser limit. Through time-resolved two-photon photoemission (TR-2PPE) spectroscopy in crystalline pentacene and tetracene, our lab has recently provided the first spectroscopic signatures in singlet fission of a critical intermediate known as the multiexciton state (also called a correlated triplet pair). More importantly, we found that population of the multiexciton state rises at the same time as the singlet state on the ultrafast time scale upon photoexcitation. This observation does not fit wi...
268 citations
TL;DR: In this article, the authors report on highly efficient organic light emitting diodes (OLEDs) consisting of only two organic layers, and the key to the simplification is the direct injection of holes into the wide band gap hole transport material 4,4′,4″-tris(N-carbazolyl)-triphenyl amine (highest occupied molecular orbital is 5.9eV) through an indium tin oxide/tungsten oxide (WO3) anode.
Abstract: The authors report on highly efficient organic light emitting diodes (OLEDs) consisting of only two organic layers. The key to the simplification is the direct injection of holes into the wide band gap hole transport material 4,4′,4″-tris(N-carbazolyl)-triphenyl amine (highest occupied molecular orbital is 5.9eV) through an indium tin oxide/tungsten oxide (WO3) anode. Kelvin probe analysis has revealed an extremely high work function of 6.4eV for WO3. The efficiencies of the simplified OLEDs exceed 40lm∕W and 45cd∕A at a brightness of 100cd∕m2, unsurpassed by other comparably simple OLED devices. Therefore, our OLED architecture demonstrates highly efficient, yet easy to fabricate devices.
267 citations
TL;DR: A new type of fluorescence sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines.
Abstract: A new type of fluorescence sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines. The sensory material is primarily based on well-defined nanofibers fabricated from an n-type organic semiconductor molecule, N-(1-hexylheptyl)perylene-3,4,9,10-tetracarboxyl-3,4-anhydride-9,10-imide. Upon deposition onto a substrate, the entangled nanofibers form a meshlike, highly porous film, which enables expedient diffusion of gaseous analyte molecules within the film matrix, leading to milliseconds response for the vapor sensing.
266 citations
TL;DR: In this article, the authors review recent work on organic molecular beam deposition (OMBD) with emphasis on growth studies beyond the first monolayer, i.e. the evolution of the film structure and morphology.
Abstract: We review recent work on organic molecular beam deposition (OMBD) with emphasis on growth studies beyond the first monolayer, i.e. the evolution of the film structure and morphology. First, we briefly discuss general issues related to growth physics, including epitaxial relations, surface and interface energies, growth modes, correlation functions, dynamic scaling, and growth exponents. We also point out the general features that distinguish organic systems from inorganic systems, such as the different interaction potentials and the internal degrees of freedom of organic molecules. Then we discuss selected case studies, organised according to the role of the substrate (insulators, metals, semiconductors), covering examples from various organic semiconductors, namely perylene-derivatives (in particular diindeno-perylene (DIP) and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA)), phthalocyanines, and oligoacenes (anthracene, tetracene, pentacene). Finally, we briefly discuss organics-based heterostructures and indicate some open problems and future directions. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
265 citations