Functional Electronic Materials

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. 

This article has been focussing on poly(phenylene)s with 1,4-(pnra-)phenylene units since these polymers play a key role in the synthesis-driven search for electronic materials. From this article it has become clear that poly(phenylene) chemistry has not restricted its attention to linear (1D-) structures, but has more recently developed into 2D- and 3D-structures as well, the latter serving as functional shape-persistent nanoparticlcs. 

There are many organic compounds with useful electronic and/or optical properties and with sufficiently high volatility to be evaporable at a temperature well below that at which decomposition occurs. Since thermal evaporation lends itself to facile multilayering, organic compounds may be selected for use in one or more function electron injection, electron transport, hole injection, hole transport, andI or emission. A complete list of materials that have been used in OLEDs is too vast to be included here. Rather, we list those that have been most extensively studied. 

Mui, C. Growth and Functionalization of Electronic Materials. PhD Thesis, Stanford University, 2003. 

Functional siloles have found applications in the elaboration of silole-containing tt-conjugated systems. Because of its unique electronic properties, the introduction of a silole component or a silole cooligomer into an unsaturated chain should be a promising route to novel --electronic materials and, in this connection, the preparation of new heterocyclopentadiene monomeric precursors remains a current challenge. 

Work Function (WF) plays a key role in the physics and chemistry of materials. Phenomena such as the semiconductor field effect, photo- and thermionic electron emission (Allen and Gobelli, 1962), catalysis (Vayenas et al 1996), and the like are dominated by the WF. This fundamental property of electronic materials is defined as the minimum work required to extract an electron from the Fermi level Ep of a conducting phase, through the surface and place it in vacuum just outside the reach of the electrostatic forces of that phase (Trasatti and Parsons, 1986). The reference level for this transfer is thus called the vacuum reference level. Because even a clean surface is a physical discontinuity, a surface dipole t] with its associated electric field always appears at the surface of the condensed phase. Thus, the work of extracting the electron can be conceptually divided between the work required to... 

The Kelvin probe (a vibrating capacitor) is used to measure the difference in work function of two electronic materials. It is often incorrectly called a Contact Potential Difference (CPD) measurement. Explain why this term is incorrect. 

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