When light falls on a material, such as a green leaf or the retina, certain molecules transport energy and charge. This ultimately leads to the separation of charges and the generation of electricity. Molecular funnels, so-called conical intersections, ensure that this transport is highly efficient and directed.

An international team of physicists has now observed that such conical intersections also ensure a directed energy transport between neighboring molecules of a nanomaterial. Theoretical simulations have confirmed the experimental results. Until now, scientists had observed this phenomenon only within one molecule. In the long term, the results could help to develop more efficient nanomaterials for organic solar cells, for example. The study, led by Antonietta De Sio, University of Oldenburg, and Thomas Frauenheim, University of Bremen, Germany, was published in the current issue of the scientific journal Nature Nanotechnology.

Photochemical processes play a major role in nature and in technology: When molecules absorb light, their electrons transit to an excited state. This transition triggers extremely fast molecular switching processes. In the human eye, for example, the molecule rhodopsin rotates in a certain way after absorbing light and thus ultimately triggers an electrical signal—the most elementary step in the visual process.