Long-range transport in organic materials via strong light-molecule coupling


  Tal Schwartz  ,  Georgi Rozenman  ,  Katherine Akulov  ,  Adina Golombek  
Tel Aviv University

 

Electronics excitations in organic materials are often described by Frenkel excitons, whose wavefunctions are tightly localized on the individual molecules, which results in short-range, nanoscale transport. However, under strong light-molecule coupling, new quantum states, known as cavity polaritons, are formed and the wavefunctions describing the coupled system extend over distances much larger than the molecular scale. Using time-resolved microscopy we directly show that this fundamental modification in the nature of the system induces long-range transport in organic materials and propagation over several microns. By following the motion of polaritons in real-time we measure the propagation velocity of polaritons and we find that it is surprisingly lower than expected from the current models. Our approach sheds new light on the fundamental characteristics of polaritons and can provide critical information for the design of future organic-electronics devices, which will harness the polaritonic properties to overcome the poor conductance of organic materials.