This review covers the various classes of molecular structures that may be used as the basis for the synthesis of organic semiconductors that favor electron transport in field-effect transistors and related electronic and optoelectronic devices. The types of compounds include tetracarboxylic diimides, heterocyclic oligomers, fullerenes, and metal complexes. Approaches to polymers are also mentioned. Although brief discussions of transistor operation and applications are included, the emphasis is on the rationale for choosing these structures, and synthetic routes to them. Performance of exemplary compounds in transistors is also discussed.

The Seebeck coefficient, a defining parameter for thermoelectric materials, depends on the contributions to conductivity of charge carriers at energies away from the Fermi level. Highly conductive materials tend to exhibit conductivity from carriers close to the Fermi level. In this article, we propose polymer blends in which ground state hole carriers, created by doping a minor additive component, are mainly at an orbital energy set below the hole energy of the major component of the blend. Transport, however, is expected to occur through the major component. This leads to a regime in which hole conductivity and Seebeck coefficient may be increased in parallel. While the absolute conductivity of the composite, and thus ZT, are not particularly high, this work demonstrates a route for designing thermoelectric materials in which increases in Seebeck coefficient and conductivity do not cancel each other.

A class of hybrid oligosilane–arene materials outperforms the σ- and π-conjugated parent structures.