"What we see here is energy transfer that is much faster than in any semiconductor," says Jakob Heier. The physicist works in Empa's Functional Polymers lab, and the discovery he has made with his team could cause a stir in many areas—such as sensor technology, optical data transmission or the fabrication of organic solar cells. We are talking about islands of dye molecules with a perfect, internal structure. Among experts, such structures are called J-aggregates. Although they have been known for more than 80 years, they recently attracted renewed attention in research. This is due to the special electronic inner life of these dye islands.