Speaker
Description
This presentation will summarise a body of work emanating from our research group over the past five years. It focuses on correlating the properties of excitons with the complex solid-state microstructure in macromolecular semiconductors. In general, the optical properties of polymeric semiconductors are governed fundamentally by the interplay of electronic interactions occurring within a given polymer chain and those occurring between chains that constitute crystalline motifs. The competition between through-bond (intrachain) and through-space (interchain) electronic coupling determines two-dimensional spatial extent of excitons. The balance of these competing interactions depends very sensitively on solid-state microstructure of the polymer film (e.g. polycrystalline, semicrystalline with amorphous domains, etc.) Via analysis of absorption and photoluminescence spectral lineshapes, we have developed a protocol by which the spatial coherence of excitons, the degree to which the disordered landscape is correlated, and the interplay of intra- and interchain excitonic coupling in disordered polymeric semiconductors can be predicted when processing thin films within devices. I will outline novel ultrafast optical probes developed to probe in more detail the spectral correlations arising from excitonic properties of this class of materials.
