Uniaxial Alignment of Polycyclic Aromatic Hydrocarbons by Solution Processing

Pisula, Wojciech; Tomović, Željko; Stepputat, Michael; Kolb, Ute; Pakuła, Tadeusz; Müllen, Kläus

doi:10.1021/cm050008d

Cited by 78 publications

(47 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[143] Based on this technique, the alignment of several HBC derivatives on isotropic substrates has been successfully demonstrated. [143][144][145] An optical image and high resolution (HR) TEM image from a zone-cast hexa-peri-hexabenzocoronene (HBC-C 12 ) layer are shown as examples in Figure 17b and c, respectively. From these images, it can be observed that HBC-C 12 forms aligned columnar structures along the casting direction.…”

Section: Alignment Of Organic Semiconductors Through Solution Processingmentioning

confidence: 99%

Controlled Deposition of Crystalline Organic Semiconductors for Field‐Effect‐Transistor Applications

et al. 2009

View full text Add to dashboard Cite

The search for low‐cost, large‐area, flexible devices has led to a remarkable increase in the research and development of organic semiconductors, which serve as one of the most important components for organic field‐effect transistors (OFETs). In the current review, we highlight deposition techniques that offer precise control over the location or in‐plane orientation of organic semiconductors. We focus on various vapor‐ and solution‐processing techniques for patterning organic single crystals in desired locations. Furthermore, the alignment of organic semiconductors via different methods relying on mechanical forces, alignment layers, epitaxial growth, and external magnetic and electric fields are surveyed. The advantages, limitations, and applications of these techniques in OFETs are also discussed.

show abstract

Section: Alignment Of Organic Semiconductors Through Solution Processingmentioning

confidence: 99%

Controlled Deposition of Crystalline Organic Semiconductors for Field‐Effect‐Transistor Applications

et al. 2009

View full text Add to dashboard Cite

show abstract

“…In the ideal case, the columns have to bridge a gap of several micrometers between the anode and cathode, all within a defect‐free and long‐range‐ordered film. Suitable processing techniques can provide the high degree of macroscopic orientation necessary for such devices to perform well 7–10. Discotics can organize themselves in two different ways on surfaces, either edge‐on or face‐on.…”

Section: Introductionmentioning

confidence: 99%

Dendritic Morphology in Homeotropically Aligned Discotic Films

et al. 2007

Self Cite

View full text Add to dashboard Cite

A hexa‐alkylether‐substituted hexa‐peri‐hexabenzocoronene, as a discotic liquid crystal, spontaneously homeotropically self‐orients when cooled from the isotropic phase. During this process, a dendritic morphology is formed in which a significant optical difference is observed between the dendritic shapes and their periphery. However, local structural analysis using microfocus synchrotron radiation experiments demonstrate that there is an identical supramolecular order in both areas. Three‐dimensional confocal surface measurements reveal that these dendritic structures result from a dewetting process, which occurs during solidification. Thereby, the contact area between the organic material and the surface is reduced. These results are important for the design of organic electronics, since the reduction of the contact area in an electronic device might inhibit the charge transport between the discotic semiconductor and the electrode.

show abstract

“…This makes processing from solution and deposition of thin films, as required for electronic devices, difficult [92][93][94][95][96][97][98][99][100]. Attachment of solubilizing alkyl groups is then indispensable -as long as they do not obstruct the extended π-conjugation.…”

Section: Expanding Synthetic Chemistry To Complex Macromoleculesmentioning

confidence: 99%

Graphene as a Target for Polymer Synthesis

Müllen

2013

Advances in Polymer Science

Self Cite

View full text Add to dashboard Cite

Graphene has remarkable physical properties, but existing production methods have severe deficiencies that limit its potential use in robust technologies. Opening a reliable and efficient synthetic route to graphene and its functionalized derivatives offers a path to overcome this obstacle for its practical application. Graphene can be regarded as a two-dimensional polymer (2D), and it is here argued that it, along with its derivatives, represents a realistic yet challenging target for polymer synthesis.In order to demonstrate the possibility of such syntheses, an overview is presented on the evolution of phenylene-based macromolecules. It is shown how classical linear polyphenylenes can be expanded to increasingly more sophisticated structures involving two-and three-dimensional (3D) polyphenylene architectures. A crucial aspect of the meticulous synthetic design of these molecules has been the avoidance of defects within the structures, resulting in the precise control of their physical, especially optoelectronic, properties.Linear conjugated polymers with defined optical properties have been made by controlling the degree of torsion between the benzene rings. This has included the development of efficient routes to ladder-type polymers and of step-ladder materials. Planar graphene molecules, or nanographenes, in a range of sizes and shapes have been fabricated by the controlled cyclodehydrogenation of 3D polyphenylene dendrimers. By combining knowledge gained from the synthesis of conjugated polymers, polyphenylene dendrimers, and nanographenes, it has proven feasible to make, either by solution or surface-bound methods, graphene nanoribbons with well-defined structures. These functional materials possess properties similar to graphene while displaying improved processability.Finally, we review less-sophisticated paths towards graphene materials involving processing of graphene oxide, its reduction, and its hybridization with other components. These too have a role to play in acquiring functional graphenes where K. Müllen (*) Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany e-mail: muellen@mpip-mainz.mpg.de a lesser degree of control over the properties is required. This voyage of exploration towards the precise synthesis of conjugated phenylene-based polymers has thus had the dual objectives of fundamental research and practical materials science. En route we have had to meet the sometimes conflicting gauntlets thrown down by these two aims, which has at times involved trade-offs between the theoretically desirable and the reasonably accessible.

show abstract

Uniaxial Alignment of Polycyclic Aromatic Hydrocarbons by Solution Processing

Cited by 78 publications

References 44 publications

Controlled Deposition of Crystalline Organic Semiconductors for Field‐Effect‐Transistor Applications

Controlled Deposition of Crystalline Organic Semiconductors for Field‐Effect‐Transistor Applications

Dendritic Morphology in Homeotropically Aligned Discotic Films

Graphene as a Target for Polymer Synthesis

Contact Info

Product

Resources

About