Anisotropic energy transfer in crystalline chromophore assemblies
Haldar, R. / Jakoby, M. / Mazel, A. / Zhang, Q. / Welle, A. / Mohamed, T. / Krolla, P. / Wenzel, W. / Diring, S. / Odobel, F. / Richards, B. S. / Howard, I.A. / Wöll, C. (2018)
Nature Communications, 2018, 9, 4332
- Date: Oktober 2018
An ideal material for photon harvesting must allow control of the exciton diffusion length and directionality. This is necessary in order to guide excitons to a reaction center, where their energy can drive a desired process. To reach this goal both of the following are required; short- and long-range structural order in the material and a detailed understanding of the excitonic transport. Here we present a strategy to realize crystalline chromophore assemblies with bespoke architecture. We demonstrate this approach by assembling anthracene dibenzoic acid chromophore into a highly anisotropic, crystalline structure using a layer-by-layer process. We observe two different types of photoexcited states; one monomer-related, the other excimer-related. By incorporating energy-accepting chromophores in this crystalline assembly at different positions, we demonstrate the highly anisotropic motion of the excimer-related state along the  direction of the chromophore assembly. In contrast, this anisotropic effect is inefficient for the monomer-related excited state.