Optical properties of oligothiophene inclusion compounds

Single quasi-planar thiophene oligomers, electronically decoupled in the solid state, are obtained by inclusion of the molecules in perhydrotriphenylene. The suppression of the collective excitations, which dominate the optical properties of aggregated oligothiophenes, evidences the spectroscopical properties of the single molecules. The radiative recombination process takes place from two emitting states, separated by a small potential barrier. The conformational mobility ensured by the cylindrical channels of the host compound, allows torsional relaxation in the excited state even at low temperatures.