Kekulé structures belong to the classical concepts of theoretical chemistry of polycyclic conjugated molecules and, in particular, of benzenoid hydrocarbons [1 – 3]. Nevertheless, it was only quite recently recognized [4] that in addition to the standard representation of a Kekulé structure (in which the locations of the double bonds are indicated), also an “algebraic” representation is possibl...

We present magnetoconductivity and magnetoluminescence measurements in sandwich devices made from films of a π-conjugated molecule and demonstrate effects of more than 30 and 50% magnitude, respectively, in fields of 100 mT at room-temperature. It has previously been recognized that the effect is caused by hyperfine coupling, and that it is phenomenologically similar to other magnetic field eff...

A simple synthesis of highly planar extended π-electron molecules is particular interest for the development efficient nonfullerene acceptors in organic solar cells with high light absorption and mobility. Herein, two small-molecule (MPU7 MPU8) a diketopyrrolopyrrole core connected to CPTCN end-capping groups (A2) via thienylethynylselenophene (MPU7) or thienylethynylthiophene (MPU8) linkers ar...

Molecular electrostatic potentials (MESP) of the most common building blocks of organic π-conjugated systems, viz. ethylene, acetylene, benzene, furan, pyrrole, thiophene and phenylvinylene, are examined at the B3LYP/6-311++G(2d,2p) level. The topography of MESP is employed for mapping the strength of electronic conjugation between these building blocks. When electron-rich molecular regions are...

We have performed momentum dependent electron energy-loss studies of the electronic excitations in sexithiophene and compared the results to those from parent oligomers. Our experiment probes the dynamic structure factor S(q, ω) and we show that the momentum dependent intensity variation of the excitations observed can be used to extract the size of the electron-hole pair created in the excitat...

The interaction of delocalized π-electrons with molecular vibrations is key to charge transport processes in π-conjugated organic materials based on aromatic monomers. Yet the role that specific aromatic motifs play on charge transfer is poorly understood. Here we show that the molecular edge topology in charged catacondensed aromatic hydrocarbons influences the Herzberg-Teller coupling of π-el...

We measured the adsorption geometry of single molecules with intramolecular resolution using noncontact atomic force microscopy with functionalized tips. The lateral adsorption position was determined with atomic resolution, adsorption height differences with a precision of 3 pm, and tilts of the molecular plane within 0.2°. The method was applied to five π-conjugated molecules, including three...

The feasibility of using π-conjugated polymers as next-generation electronic materials is extensively studied; however, their charge mobilities are lower than those of inorganic materials. Here we demonstrate a new design principle for increasing the intramolecular charge mobility of π-conjugated polymers by covering the π-conjugated chain with macrocycles and regularly localizing π-molecular o...

Dibenzo[a,e]pentalene derivatives as nonalternant conjugated hydrocarbons are attractive for use ambipolar or n-type semiconductors in field-effect transistors. For organic semiconductors, not only the energy levels of frontier molecular orbitals but also their solid-state packing is crucial good charge transport abilities. The introduction fluorine atoms into can lead to a closer solid state, ...