Functional Electronic Materials Research Articles

Emerging Prospects for Unusual Aromaticity in Organic Electronic Materials: The Case for Methano[10]annulene

AbstractUnusual aromatics outside of the 6π‐electron motif offer promise for functional electronic materials, and we frame this claim in the context of 10π‐electron aromatics. The evolution of our understanding of 10π‐electron aromatics is discussed briefly, from azulene to the [10]annulenes to finally 1,6‐methano[10]annulene. A survey of annulene research of both fundamental and applied nature is then presented. Finally, our recent contributions to this area are highlighted with a comparison of annulene‐based electronic materials to more classical benzenoid counterparts. The annulene core greatly facilitates the delocalization of mobile charges as determined through voltammetry and spectroelectrochemistry. We show that this important hydrocarbon can indeed be viewed as a viable building block for advanced polymeric semiconducting materials.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

ホウ素を含む機能性π電子系材料の設計と合成

Utilization of boron, a group 13 element, as a key element for developing new functional electronic and optoelectronic materials is an important direction in the organoboron chemistry. Boron has several characteristic features, such as trigonal planar geometry for trivalent boron compounds, high Lewis acidity, and effective orbital interaction with π-conjugated frameworks through the vacant p-orbital (i.e., ρπ-π* conjugation). Exploiting these features of the boron element for molecular designs allows us to create sophisticated π-electron materials having attractive photophysical and electronic properties. We here present some progress in our chemistry, including B, B', B-trianthrylborazine (B3N3)-based molecular bundles, boryl-substituted thienylthiazole π-electron systems with intramolecular B-N coordination, borole- and dibenzoborole-based π-conjugated compounds, and boryl-substituted emissive organic solids.

Some fundamental and applicative properties of [polymer/nano-SiC] hybrid nanocomposites

Hybrid nanocomposites which combine polymer as host matrix and nanocrystals as active elements are promising functional materials for electronics, optics or photonics. In these systems, the physical response is governed by the nanocrystal features (size, surface and defect states), the polymer properties and the polymer-nanocrystal interface. This work reviews some selective nanostructured architectures based on active elements such as silicon carbide (SiC) nanocrystals and polymer host matrices. Beyond an overview of some key properties of the nanocrystals, a main part will be devoted to the electro-optical (EO) properties of SiC based hybrid systems where SiC nanocrystals are embedded in polymer matrices of different chemical nature such as poly-(methylmethacrylate) (PMMA), poly-vinylcarbazole (PVK) or polycarbonate. Using this approach, the organic-inorganic interface effects are emphasised with regard to the dielectric or hole transporting behaviour of PMMA and PVK respectively. These effects are illustrated through different EO responses associated with hybrid composites based on PMMA or PVK.

Templating Effects and Optical Characterization of Copper (II) Phthalocyanine Nanocrystallites Thin Film: Nanoparticles, Nanoflowers, Nanocabbages, and Nanoribbons

The recent emergence of molecular ultrathin films as candidates for functional electronic materials and photo catalyst has prompted numerous investigations on their crystalline structure and thin film formation. This article describes the role of the effect of the nature of substrate and substrate temperatures in molecular organization of copper (II) phthalocyanine (CuPc) on gold coated quartz substrates using conventional vapor deposition at high vacuum (∼10-6 Torr). Surprisingly, the 100 nm thick CuPc films on the quartz substrates are as highly ordered as on the polycrystalline gold-coated quartz substrates. Importantly, the molecular orientation in the two cases is radically different. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) observations of the ordered crystalline films indicated that domains are grown from the bottom to the top of the film and are densely packed with little grain boundary. X-ray diffraction (XRD) pattern shows a sharp intense pea...

Epitaxy and Molecular Organization on Solid Substrates

The recent emergence of molecular films as candidates for functional electronic materials has prompted numerous investigations of the underlying mechanisms responsible for their structure and formation. This review describes the role of epitaxy in molecular organization on crystalline substrates. A much-needed grammar of epitaxy is presented that classifies the various modes of epitaxy according to transformation matrices that relate the overlayer lattice to the substrate lattice. The different modes of epitaxy can be organized hierarchically to reflect the balance of overlayer–substrate and molecule–molecule energies. In the case of molecular overlayers, the mismatch of overlayer and substrate symmetries commonly leads to coincident epitaxy in which some of the overlayer lattice points do not reside on substrate lattice points. Analyses of numerous reported epitaxial molecular films reveal that coincidence is quite common even though, based on overlayer–substrate interface energies alone, not as energetically favorable as commensurism. The prevalence of coincidence can be attributed to overlayer elastic constants, associated with molecule–molecule interactions within the overlayer, that are larger than the elastic constants of the overlayer–substrate interface. This condition facilitates prediction of the epitaxial configuration and overlayer structure through simple and comparatively efficient geometric modeling that does not require the input of potential energies, while revealing the role of phase coherence between the overlayer and substrate lattices.

High-resolution inkjet printing of all-polymer transistor circuits.

Direct printing of functional electronic materials may provide a new route to low-cost fabrication of integrated circuits. However, to be useful it must allow continuous manufacturing of all circuit components by successive solution deposition and printing steps in the same environment. We demonstrate direct inkjet printing of complete transistor circuits, including via-hole interconnections based on solution-processed polymer conductors, insulators, and self-organizing semiconductors. We show that the use of substrate surface energy patterning to direct the flow of water-based conducting polymer inkjet droplets enables high-resolution definition of practical channel lengths of 5 micrometers. High mobilities of 0.02 square centimeters per volt second and on-off current switching ratios of 10(5) were achieved.

Computational materials design and processing: perspectives for atomistic approaches

Theoretical and computational methods on the atomistic level have now matured to a point where their impact on the design of materials and their processing is becoming evident. This contribution provides an overview and critical assessment of the major current computational approaches with special emphasis on density functional methods. This is illustrated by characteristic examples including the chemisorption of a silane molecule on reconstructed Si(001) surfaces, the adhesion of NH 3 to a CuO(111) surface, structural properties of LaNi 5, the optical properties of ruby, and the magnetic properties of Co/Cu heterostructures. Immediate opportunities for atomistic approaches can be found in the development of novel functional electronic, optical and magnetic materials whereas the atomistic simulation of dynamic processes including phenomena such as fatigue and corrosionwhile undeniably atomistic in origin—may need innovative conceptual and theoretical developments in order to bridge the gaps between atomistic, mesoscopic, and macroscopic length and time scales.

Functional Materials for Electronics

Functional Materials for Electronics