Communication: Time-resolved fluorescence of highly single crystalline molecular wires of azobenzene

We report the enhanced fluorescence with the remarkably long lifetime (1.17 ns) in the first excited state (S(1)) of highly crystalline molecular wires of azobenzene at the excitation wavelength of 467 nm for the first time. This observation suggests that trans-cis photoisomerization through the rotation or inversion mechanism may not be a favorable pathway after excitation to the S(1) state in highly single crystalline molecular wires of azobenzene due to the hindered motion within densely packed crystal structure. We also measured the fluorescence lifetime image of a single crystalline molecular wire of azobenzene, indicating that the lifetime was remarkably uniform and that there was only a very minor variation within the crystal.