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Results of thermally stimulated photoluminescence (TSL) measurements in poly(2,5-dioctoxy p-phenylene vinylene) (DOO–PPV) are reported. The obtained results are analyzed in terms of the hopping model of TSL in disordered organic materials. It is shown that the experimentally obtained TSL curve can be fitted on the basis of a double-peak Gaussian density-of-states distribution. The upper peak is associated with intrinsic localized states while the lower one can be ascribed to aggregates. The latter assignment is also supported by measurements of steady-state and time-resolved photoluminescence in DOO–PPV films and solutions. Possible mechanisms of charge carrier photogeneration in DOO–PPV are discussed.

We report on photoluminescence (PL) and thermally stimulated luminescence (TSL) in highly ordered nanostructures of para‐sexiphenyl (PSP) grown by hot wall epitaxy (HWE). A low‐energy broad band is observed in the PL spectra that can be attributed to the emission from molecular aggregates. While the intrinsic exciton emission in steady‐state PL dominates at low temperatures, the emission from aggregates increases with elevating temperature and its magnitude depends sensitively on film preparation conditions. Time‐resolved PL measurements showed that the aggregate emission decays with a life‐time of ≈ 4 ns, which is approximately an order of magnitude larger than the lifetime of singlet excitons. TSL data suggests the presence of an energetically disordered distribution of localized states for charge carriers in PSP films, which results from an intrinsic disorder in this material. A low‐temperature TSL peak with the maximum at around 30 K evidences for a weak energy disorder in PSP films, and has been interpreted in terms of a hopping model of TSL in disordered organic materials.