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.

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White-light emitting porous SiO 2 :C layers on silicon wafers have been fabricated by oxidation of carbonized porous silicon.The study was focused mainly on the identification of the mechanism of light emission and photo-induced degradation. The effect of carbonization temperature and exposure to intense ultraviolet irradiation on the photoluminescence (PL) properties was studied by steady state and time-resolved PL measurements. Two types of photo-induced degradation phenomena were observed: reversible and irreversible. The irreversible degradation is suggested to be associated with photo-induced chemical interaction of light emitting material with atmospheric oxygen. It is demonstrated that irreversible degradation can be reduced by encapsulation of the lightemitting material. The structural configuration of light-emitting centers and mechanism of reversible degradation are discussed.

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