Long-Lived Photocharges in Supramolecular Polymers of Low-Band-Gap Chromophores.

Photoinduced charge separation in supramolecular aggregates of π-conjugated molecules is a fundamental photophysical process and a key criterion for the development of advanced organic electronics materials. Herein, the self-assembly of low-band-gap chromophores into helical one-dimensional aggregates, due to intermolecular hydrogen bonding, is reported. 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. These findings demonstrate that the confinement of organic semiconductors into one-dimensional aggregates results in a considerable stabilization of charge carriers for a variety of π-conjugated systems, which may have implications for the design of future organic electronic materials.