Molecular doping: The standard model for molecular p-doping of organic semiconductors (OSCs) assumes integer charge transfer between OSC and dopant. This is in contrast to an alternative model based on intermolecular complex formation instead. By systematically varying the acceptor strength it was possible to discriminate the two models. The latter is clearly favored, suggesting strategies for the chemical design of more efficient molecular dopants.

Gedopte Moleküle: Das Standardmodell für die molekulare Dotierung organischer Halbleiter (OSCs) basiert auf ganzzahligem Ladungstransfer zwischen OSC und Dotand. Ein alternatives Modell geht von der Bildung eines Komplexes aus OSC und Dotand aus. Experimente unter systematischer Variation der Akzeptorstärke sprechen klar für letzteres Modell, was zum gezielten chemischen Design effizienterer molekularer Dotanden beitragen könnte.

A detailed structural study of the bulk and thin film phases observed for two potential high performance organic semi conductors has been carried out. The molecules are based on [1]benzothieno[3,2 b]benzothiophene (BTBT) as conjugated core and octyl side groups, which are anchored either symmetrically at both sides of the BTBT core (C 8 −BTBT−C 8 ) or nonsymmetrically at one side only (C 8 −BTBT). Thin films of different thickness (8−85 nm) have been prepared by spin coating for both systems and analyzed by combining specular and grazing incidence X ray diffraction. In the case of C 8 −BTBT−C 8 , the known crystal structure obtained from single crystal investigations is observed within all thin films, down to a film thickness of 9 nm. In the case of C 8 −BTBT, the crystal structure of the bulk phase has been determined from X ray powder diffraction data with a consistent matching of experimental and calculated X ray diffraction patterns (Rwp = 5.8%). The packing arrangement of C 8 −BTBT is similar to that of C 8 −BTBT−C 8 , that is, consisting of a lamellar structure with molecules arranged in a "herringbone" fashion, yet with lamellae composed of two head to head (or tail to tail as the structure is periodic) superimposed molecules instead of only one molecule for C 8 −BTBT−C 8 . As for C 8 −BTBT−C 8 ,we demonstrate that the same phase is observed in bulk and thin films for C 8 −BTBT whatever the film thickness investigated.

A straightforward synthesis of a bis(pyrrolo)tetrathiafulvalene (BPTTF)-based tetratopic ligand bearing four pyridyl units is described. The first example of a TTF-based self-assembled cage has been produced from this redox-active ligand through metal-directed synthesis with a cis-coordinated square-planar Pt(II) complex. The resulting cage corresponds to a trigonal-prismatic structure, as shown by X-ray crystallography. A UV-vis titration indicated that the electron-rich cavity can be used to incorporate one molecule of tetrafluorotetracyano-p-quinodimethane (TCNQF(4)).

The formation of the two dimeric species [(TTF)2]+* and (TTF+*)2 can be monitored by complexation of Na+ on a calix[4]arene-TTF assembly.

Polymorphism is an interesting phenomenon critical to our understanding of structure−property relationships in solid-state functional materials. We report the synthesis and structural characterization of two polymorphic forms of a DPP-Boc derivative, DPP4T-α and DPP4T-β, as well as the study of their optical properties. Thin film studies have been carried out to identify the specific polymorphic form that exists in contact with the substrate and also to obtain a better understanding of the interface morphology with respect to crystal packing. The two polymorphs, DPP4T-α and DPP4T-β, have been structurally characterized using single crystal/powder X-ray diffraction data with a detailed analysis of Hirshfeld surfaces and fingerprint plots facilitating a comparison of the type and nature of intermolecular interactions in the supramolecular architectures. DPP4T-α crystallizing in a space group P2 1 /c with Z′ = 0.5 interlinked via C−H•••O/π and π•••π interactions forms 2D herringbone sheets. In the polymorph DPP4T-β with space group P1 and Z′ = 1, the crystal packing is stabilized by CH•••π and π•••π interactions forming a columnar network. From considerations of density and from lattice energy calculations, it can be concluded that the αform is more stable in bulk. In thin films the β-form was found to be more stable. This work gives a unique example where the polymorphism could be identified and separated both in the bulk and in thin films. This study on the structural effects of polymorphism is useful for further development of DPP-based materials and also for targeted design of other functional materials.

A kinetically stable self-assembled redox-active triangle is isolated. The resulting electron-donating cavity, which incorporates three BPTTF units, exhibits a remarkable binding ability for electron-deficient C(60), supported by a favorable combination of structural and electronic features.

The regiospecific total synthesis and characterization of anti-isomers of 2,8-dialkylanthradithiophenes are described. The "anti" structure of the ADT derivatives is demonstrated by 13 C NMR as well as single crystal X-ray diffraction.