Since the discovery of highly conducting polyacetylene by Shirakawa, MacDiarmid, and Heeger in 1977, π-conjugated systems have attracted much attention as futuristic materials for the development and production of the next generation of electronics, that is, organic electronics. Conceptually, organic electronics are quite different from conventional inorganic solid state electronics because the structural versatility of organic semiconductors allows for the incorporation of functionality by molecular design. This versatility leads to a new era in the design of electronic devices. To date, the great number of π-conjugated semiconducting materials that have either been discovered or synthesized generate an exciting library of π-conjugated systems for use in organic electronics. 11 However, some key challenges for further advancement remain: the low mobility and stability of organic semiconductors, the lack of knowledge regarding structure property relationships for understanding the fundamental chemical aspects behind the structural design, and realization of desired properties. Organic field-effect transistors (OFETs) are a kind of device consisting of an organic semiconducting layer, a gate insulator layer, and three terminals (drain, source, and gate electrodes). OFETs are not only essential building blocks for the next generation of cheap and flexible organic circuits, but they also provide an important insight into the charge transport of πconjugated systems. Therefore, they act as strong tools for the exploration of the structure property relationships of πconjugated systems, such as parameters of field-effect mobility (μ, the drift velocity of carriers under unit electric field), current on/off ratio (the ratio of the maximum on-state current to the minimum off-state current), and threshold voltage (the minimum gate voltage that is required to turn on the transistor). 17 Since the discovery of OFETs in the 1980s, they have attracted much attention. Research onOFETs includes the discovery, design, and synthesis of π-conjugated systems for OFETs, device optimization, development of applications in radio frequency identification (RFID) tags, flexible displays, electronic papers, sensors, and so forth. It is beyond the scope of this review to cover all aspects of π-conjugated systems; hence, our focus will be on the performance analysis of π-conjugated systems in OFETs. This should make it possible to extract information regarding the fundamental merit of semiconducting π-conjugated materials and capture what is needed for newmaterials and what is the synthesis orientation of newπ-conjugated systems. In fact, for a new science with many practical applications, the field of organic electronics is progressing extremely rapidly. For example, using “organic field effect transistor” or “organic field effect transistors” as the query keywords to search the Web of Science citation database, it is possible to show the distribution of papers over recent years as shown in Figure 1A. It is very clear

Semiconducting π-conjugated systems in field-effect transistors: a material odyssey of organic electronics.

Over the past 20 years, organic transistors have developed from a laboratory curiosity to a commercially viable technology. This critical review provides a short summary of several important aspects of organic transistors, including materials, microstructure, carrier transport, manufacturing, electrical properties, and performance limitations (200 references).

Organic thin-film transistors.

Remarkable progress has been made in developing high performance organic field-effect transistors (OFETs) and the mobility of OFETs has been approaching the values of polycrystalline silicon, meeting the requirements of various electronic applications from electronic papers to integrated circuits. In this review, the key points for development of high mobility OFETs are highlighted from aspects of molecular engineering, process engineering and interface engineering. The importance of other factors, such as impurities and testing conditions is also addressed. Finally, the current challenges in this field for practical applications of OFETs are further discussed.

25th anniversary article: key points for high-mobility organic field-effect transistors.

Organic semiconductors have attracted a lot of attention since the discovery of highly doped conductive polymers, due to the potential application in field-effect transistors (OFETs), light-emitting diodes (OLEDs) and photovoltaic cells (OPVs). Single crystals of organic semiconductors are particularly intriguing because they are free of grain boundaries and have long-range periodic order as well as minimal traps and defects. Hence, organic semiconductor crystals provide a powerful tool for revealing the intrinsic properties, examining the structure–property relationships, demonstrating the important factors for high performance devices and uncovering fundamental physics in organic semiconductors. This review provides a comprehensive overview of the molecular packing, morphology and charge transport features of organic semiconductor crystals, the control of crystallization for achieving high quality crystals and the device physics in the three main applications. We hope that this comprehensive summary can give a clear picture of the state-of-art status and guide future work in this area.

Organic semiconductor crystals

The advantages of organic field-effect transistors, such as low cost, mechanical flexibility and large-area fabrication, make them potentially useful for electronic applications such as flexible switching backplanes for video displays, radio frequency identifications and so on. A large amount of molecules were designed and synthesized for electron transporting (n-type) and ambipolar organic semiconductors with improved performance and stability. In this review, we focus on the advances in performance and molecular design of n-type and ambipolar semiconductors reported in the past few years.

25th Anniversary Article: Recent Advances in n‐Type and Ambipolar Organic Field‐Effect Transistors

The electrical performance of organic thin-film transistors (TFTs) often degrades when the devices are exposed to air. This is generally ascribed to the generation of trap states, [1] possibly as a result of the oxidation of the organic semiconductor. [2] One strategy to improve the stability of p-channel organic TFTs is the synthesis of conjugated semiconductors with a relatively large ionization potential. [3–8] However, most of the TFTs based on organic semiconductors with large ionization potentials reported up till now have shown carrier mobilities that are smaller than that of pentacene. Here, we report on a new organic semiconductor, di(phenylvinyl)anthracene (DPVAnt), [9] that combines large carrier mobility (similar to that of pentacene) with increased ionization potential and improved stability as compared to pentacene. DPVAnt has been synthesized by a Suzuki coupling reaction between 2,6-dibromoanthracene and 4,4,5,5-tetramethyl2-[2-phenylvinyl]-[1,3,2]dioxaborolane [9] with a yield of 85%. Pentacene has been purchased from Fluka. Both semiconductors have been purified by temperature gradient sublimation in a stream of inert gas. Cyclic voltammetry indicates a highest occupied molecular orbital (HOMO) energy of –5.4 eV for DPVAnt, as compared to –5.0 eV for pentacene. From UV-vis absorption spectroscopy we have determined an optical bandgap of 2.6 eV for DPVAnt and 1.8 eV for pentacene. These results are consistent with the general observation that molecules characterized by a smaller conjugated p-system have more negative HOMO energies and larger bandgaps. Simple TFT test structures have been prepared on heavily doped silicon substrates (serving as the gate electrode) with a thermally grown SiO2 gate dielectric. The dielectric surface has been treated with octadecyltrichlorosilane (OTS), [10] and the organic semiconductor has been vacuum deposited onto the substrate. Gold source/drain contacts have been thermally evaporated throughashadowmask(Fig. 1a).Duringthedeposition of the semiconductor, the substrates are held at a temperature of 60°C for pentacene and 80°C for DPVAnt. The carrier mobilities extracted from the transfer characteristics measured in air are 1 cm 2 V –1 s –1 for pentacene and 1.3 cm 2 V –1 s –1 for DPVAnt (Fig. 1b). Both TFTs have an on/off current ratio of 10 7 and a subthreshold swing of 500 mV decade –1 . Perhaps the most striking differences between the two devices are the much more negative turn-on and threshold voltages of the DPVAnt transistor (Vturn-on =– 14 V,Vth = –16 V) as compared to the pentacene TFT (Vturn-on =– 2 V,Vth = –5 V). The exact reason for this difference is not known, but it may be related to the more negative HOMO energy of DPVAnt as compared to pentacene. As shown by the atomic force microscopy (AFM) images in Figure 1c and d, both semiconductors form well-ordered polycrystalline films, which is a prerequisite for obtaining large carriermobilities.

/pdf/organic-transistors-based-on-di-phenylvinyl-anthracene-2jd1znu99b.pdf

Organic Transistors Based on Di(phenylvinyl)anthracene: Performance and Stability**

Photosensitive films composed of dye, initiator, acrylic monomers, and polymeric film-forming binder, and their
use in recording volume phase transmission and reflection holograms are described. Systematic variation of monomer-binder
combinations reveals that the maximum attainable index modulation (hologram efficiency) increases with increasing
difference between the refractive indices of monomer and binder. Addition of plasticizer is also useful for increasing index
modulation. Thermal and wet chemical processing methods for altering hologram properties are described.

Photopolymers for holography

Improved holographic optical elements are disclosed that contain a reflection hologram. Also, an improved process for forming reflection hologram.

Holographic optical elements having a reflection hologram formed in a photopolymer

The invention provides metal compositions, including silver compositions, and thermal imaging donors prepared with the compositions. The donors are useful for thermal transfer patterning of a metal layers and optionally, a corresponding proximate portion of an additional transfer layer onto a thermal imaging receiver. The compositions are useful for dry fabrication of electronic devices. Also provided are patterned multilayer compositions comprising one or more base film(s), and one or more patterned metal layers, including EMI shields and touchpad sensors.

Metal compositions, thermal imaging donors and patterned multilayer compositions derived therefrom

A pellicle comprising a thin, durable film of substantially uniform thickness which absorbs less than 10% light at wavelengths between 190 and 820 nanometers, tautly adhered to one edge of an enclosed support frame, said thin film comprising amorphous fluoropolymers having a refractive index between 1.24 and 1.41. Pellicles of this type are dust defocusing covers for photomasks and reticles used to project patterns onto light sensitive substrates such as photoresist-coated semiconductor wafers which are used in the manufacture of integrated circuits.

Amorphous fluoropolymer pellicle films

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