Functional materials/devices

The creation of functional materials, devices and systems through control of matter on the nanometer length scale (1-100 nm), and exploitation of novel phenomena and properties (physical, chemical, biological) at that length scale. 

This chapter gives a brief review of the recent progress in the application of radiation techniques for production and investigation of new functional materials, devices, and systems of nanometer sizes. The review includes the examination of widespread production methods as well as the most promising experimental data. Since the number of publications on these subjects is too many, the review quotes the most typical works on each of the considered methods. 

Radiation methods occupy an important place in the production and investigation of new functional materials, devices, and systems of nanometer size (ion-track membranes, polymeric nanocomposites, 3D nanostructures, metal nanoparticles, carbon nanostructures, etc.). The recent trend towards electronic miniaturization places at the forefront the problem of fabrication of semiconductor nanostructures, which is possible only with the use of radiation lithographic methods. The radiation modification of graphene can play a key role in the development of a new generation of industrial microchips based on graphene transistors, which will lead to a sharp increase in the operation speed and recording density of modem computer and communication systems. 

Nanotechnology has recently become one of the most exciting forefront field that has impacted several areas of material science useful in solving bioanalytical problems, including specificity, stability and sensitivity. Nanotechnology is defined as the creation of functional materials, devices and systems through control of matter at the 1-100 nm scale. It has been formd that there are dramatic changes in properties (electrical, thermal, mechanical, electronic, optical) in nano scale dimension compared to their bulk cormterparts For example, copper nanoparticles smaller than 50 nm are considered as super hard materials that do not exhibit the same... 

Nanotechnology The technology that creates functional materials, devices, and systems with novel properties and phenomena through control of matter on the scale... 

Jiangsu Key Laboratory for Carbon-Based Functional Materials Devices, Institute of Functional Nano Soft Materials (FUNSOM), Soochow University, 199 Ren ai Road, Suzhou, 215123, Jiangsu, P. R. China E-maiI zhkang suda.edu.cn... 

TT-Electron materials, which are defined as those having extended Jt-electron clouds in the solid state, have various peculiar properties such as high electron mobility and chemical/biological activities. We have developed a set of techniques for synthesizing carbonaceous K-electron materials, especially crystalline graphite and carbon nanotubes, at temperatures below 1000°C. We have also revealed new types of physical or chemical interactions between Jt-electron materials and various other materials. The unique interactions found in various Jt-electron materials, especially carbon nanotubes, will lay the foundation for developing novel functional, electronic devices in the next generation. 

Parker [55] studied the IN properties of MEH-PPV sandwiched between various low-and high work-function materials. He proposed a model for such photodiodes, where the charge carriers are transported in a rigid band model. Electrons and holes can tunnel into or leave the polymer when the applied field tilts the polymer bands so that the tunnel barriers can be overcome. It must be noted that a rigid band model is only appropriate for very low intrinsic carrier concentrations in MEH-PPV. Capacitance-voltage measurements for these devices indicated an upper limit for the dark carrier concentration of 1014 cm"3. Further measurements of the built in fields of MEH-PPV sandwiched between metal electrodes are in agreement with the results found by Parker. Electro absorption measurements [56, 57] showed that various metals did not introduce interface states in the single-particle gap of the polymer that pins the Schottky contact. Of course this does not imply that the metal and the polymer do not interact [58, 59] but these interactions do not pin the Schottky barrier. 

Chemistry is still one of the natural sciences, but in a special and unusual way. Chemists want to understand not only the substances and transformations that occur in the natural world, but also those others that are permitted by natural laws. Consequently, the field involves both discovery and creation. Chemists want to discover the components of the chemical universe—from atoms and molecules to organized chemical systems such as materials, devices, living cells, and whole organisms—and they also want to understand how these components interact and change as a function of time. However, chemical scientists consider not just the components of the chemical universe that already exist they also con-... 

By introducing the hole transport arylamine as an end cap for an anthracene backbone, Lin et al. designed a series of novel materials (207-212) (Scheme 3.65) [247]. The aim of these dual function materials is to combine the emitting property of the blue anthracene lumino-phore with the hole transport property of the triarylamine to simplify the device fabrication steps. Though the introduction of the arylamino moieties produces moderate QE (f 20%) for these materials, the OLEDs using them as emitters as well as HTMs demonstrate only moderate EL performance with a maximum luminance of 12,922 cd/m2 and 1.8 lm/W with CIE (0.15, 0.15). 

Finally, for practical reasons it is useful to classify polymeric materials according to where and how they are employed. A common subdivision is that into structural polymers and functional polymers. Structural polymers are characterized by - and are used because of - their good mechanical, thermal, and chemical properties. Hence, they are primarily used as construction materials in addition to or in place of metals, ceramics, or wood in applications like plastics, fibers, films, elastomers, foams, paints, and adhesives. Functional polymers, in contrast, have completely different property profiles, for example, special electrical, optical, or biological properties. They can assume specific chemical or physical functions in devices for microelectronic, biomedical applications, analytics, synthesis, cosmetics, or hygiene. 

The formation of photonic, electronic, ionic switching devices from molecular components and their incorporation into well-defined organized assemblies represents the next step towards the development of circuitry and functional materials at... 

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