Long-Lived Photocharges in Supramoelcular Polymers of Low-Bandgap Chromophores.

Photoinduced charge separation in supramolecular aggregates of pi-conjugated molecules is a fundamental photophysical process, and a key criterion for the development of advanced organic electronics materials. Here, we report on the self-assembly of novel low-bandgap chromophores into helical one-dimensional aggregates due to intermolecular hydrogen-bonding. The chromophores confined in these supramolecular polymers show strong excitonic coupling interactions and give rise to charge-separated states with unusually long lifetimes of several hours and charge densities of up to 5 mol% after illumination with white light. Two-contact devices exhibit increased photoconductivity and can even show Ohmic behavior. Our findings demonstrate that the confinement of organic semiconductors into one-dimensional aggregates results in a considerable stabilization of charge carriers for a variety of pi-conjugated systems, which may have implications for the design of future organic electronic materials.