Conjugated organic materials

Adding more C atoms results in more states near both the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) states shown. Because each C atom brings in, on average, half filled states, the molecular structure fills all of the orbitals for which bonding dominates without filling any of the orbitals with primarily antibonding character as in other semiconductors. Thus, 

Repeating this important point, it is possible for organic molecules to behave as do indirect-gap semiconductors, reducing the light emission probability. 

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Onodera T, Oshikiri T, Katagi H, Kasai H, Okada S, Oikawa H, Terauchi M, Tanaka M, Nakanishi H (2001) Nanowire crystals of 7t-conjugated organic materials. J Cryst Growth 229 586-590... 

Gierschner J, Comil J, Egelhaaf H-J (2007) Optical bandgaps of 7i-conjugated organic materials at the polymer limit experiment and theory. Adv Mater 19 173-191... 

A main focus of preparing metal dithiolenes functionalized with thiophene units has been for their incorporation into conjugated organic materials. On first glance, it would seem that the combination of metal dithiolenes and conjugated polymers could produce attractive new materials for use in such applications as field effect transistors and NIR optical materials. However, several challenges remain before these materials can be applied to useful... 

Supramolecular self-assembly has recently been extensively investigated as a tool to create nanostructured or hierarchically structured optoelectronically active materials from monodisperse, conjugated oligomers because such n-conjugated organic materials are interesting candidates for the fabrication of organic... 

Ordered conjugated organic materials exhibit low trap densities and high charge carrier mobilities, for both electrons and holes. As an example, in single crystals of anthracene [87], the hole and electron mobilities are approximately 1 cm V s and the crystal photoluminescence quantum yield at room temperature is almost unity. Both electroluminescence [87] and stimulated emission... 

Figure 6.1 Molecular structure of the conjugated organic materials used in this work his(terthiophene) (BT3), bis(pentathiophene) (BT5), his(heptathiophene) (BT7), a,a -dihexylpentathiophene based swivel cruciform (DHPT-SC) and (dihexylbithiophene)2-phenyl swivel cruciform (DHBTP-SC).

Fig. 3.1. Some of the more common repeating functional units in conjugated organic materials. Most organic semiconductors and conductors are made from fused or linked elements like these, which are rich in sTj hybridized carbon atoms and delocalized pi electrons. It should be noted that chemical synthesis of organic semiconductors and conductors is often not performed using these materials as starting ingredients.

The prospect of potential applications due to the extraordinary luminescence properties of conjugated organic materials have underscored the importance of gaining insights into the structure of low-lying electronic excited states of these systems. Specifically, a major issue is the relative ordering of the lowest dipole allowed singlet (PS ) state... 

In the present report we show that PhAT model, which has been successfully used for explanation of the I-V(T) characteristics in some 71-conjugated organic materials [11,12], can more comprehensively explain the temperature behavior of conductance in SWCNTs and their networks. 

The electropolymerization method of functional monomers has proved successful in many cases, in particular to incorporate various ligands and their metallic complexes, like salen [66,245], porphyrin [246], diphosphine [247], pyridine [71,80,248,249], crown ether [250,251], metallofullerene [252], tetraazacyclotetradecane [253], or Prussian blue type [254] in a conjugated organic material like PPy, PTh, or PANE Thick films are likely to be obtained provided that the polymer is redox active at the deposition potential due to this, Zotti et al. demonstrated that 5,5 -bis(3,4-(ethylenedioxy)thien-2-yl)-2,2 -bipyridine could be electropolymerized when complexed by iron and ruthenium, but not in the case of complexation by nickel or copper [71]. 

Van Hutten, P.R, H.J. Brouwer, V.V. Krasnikov, L. OuaK, U. Stahnach, and G. Hadziioannou. 1999. Effect of solid-state structure on optical properties of conjugated organic materials. Synth Met 102 1443-1446. 

FIGURE 7.1 Schematic description of the MOS-FET structure (a) and of the P-i-N diode structure (b). (c) The organic FET (OFET) top contact structure, using a conjugated organic material in the channel. 

Catalytic nucleophilic substitution reactions comprise some of the most commonly used catalytic processes in S)mthetic organic chemistry. Substitutions at aromatic and vinylic halides and sulfonates, sho vn generically in Equation 19.1, are commonplace in the preparation of pharmaceutical candidates, have often been used in the s)mtheses of natural products, and have been used many times in the syntheses of sophisticated conjugated organic materials. These metal-catalyzed reactions are typically called cross-coupling reactions. ... 

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