Keywords:organic semiconductors, exciton coherence, small molecules
Phthalocyanines thin films with macroscopic millimeter-sized grains were obtained through solution-based deposition methods pen writing. The typical grain sizes are orders of magnitude larger that the diffraction-limited focused white light beam diameters, which offers the opportunity to employ different optical spectroscopy techniques to spatially resolved the intrinsic excitonic properties within a single crystalline grain and gain insight into the fundamental correlation between the electronic states and long-range order in thin films of organic semiconductors. These experiments reveal a robust low temperature, one dimensional coherent excitonic state. The interplay between the nearest neighbor interactions and the exciton-phonon coupling results in the distruction of this state at elevated temperatures.