SUPERLATTICES AND QUANTUM-WELLS IN ORGANIC SEMICONDUCTORS - EXCITONS AND OPTICAL NONLINEARITIES

We discuss the properties of electronic excitations in organic multiple quantum well: structures consisting of alternating layers of crystalline organic semiconductors. In such media the possibility to govern spectra of electronic excitation is promising. We consider the main interactions which determine these spectra and show that in such structures the unusual channels of photo- as well as photoelectrical transformation are of interest. In terms of the small radius exciton line shifts and broadenings we consider the influence of interfaces on optical properties and analyze the first experimental observations. We discuss also the mixing of molecular configurations and Fermi resonance enhancement of optical nonlinearity in organic multilayer structures.