In this work, we investigated the process of exciton dissociation and migration in ultra-thin films of poly (9,9 dioctilfluoreno) (PFO) with a thickness smaller than the typical radius of excitonic migration (10 nm) and near to organic and inorganic semiconductor interface. The PFO films were produced using the spin-coating technique from a PFO solution in chloroform and toluene. It is known that when using chloroform as solvent, the PFO films have an amorphous structure. Thus, it was possible to obtain films that have thicknesses smaller than the radius of the exciton migration qualities, which is ideal to study photophysical processes. These films were deposited on the titanium dioxide (TiO₂) nanoparticles layer forming an organic/inorganic interface. Spectroscopic techniques such as fluorescence confocal microscopy (LSCM), fluorescence lifetime imaging microscopy (FLIM), continuous wave photoluminescence and time resolved and absorption spectroscopy were used in this study. First, the photoluminescence spectrum of PFO films were characterized by the dependence of the purely electronic transition intensity I, full width at half maximum G_o, purely electronic transition energy E and Huang-Rhys parameter S with the temperature. It was showed that the intensity can be described according to thermal activation of the exciton migration. Furthermore, the temperature introduces a thermal disorder affecting directly the conjugated segment length which is observed according to the parameters, G_o, E e S. The PFO films produced with the solvent toluene analysis showed that the fractions of β phase are already induced and that this phase is not dispersed in the amorphous matrix. On the order hand, they are shaped domains formed by β phase molecules that are related to the PFO aromatic rings organization. It was also observed that the films with thickness smaller than 10 nm prepared using chloroform, the β phase is induced, which may be occurring due to the strong interaction observed between film and substrate. Other methods reported in the literature, such as toluene steam treatment and thermal cycles of cooling/heating were used to induce β phase in amorphous PFO films as well. The exciton dissociation at the interface in films containing TiO₂/PFO interface were observed by reduction of photoluminescence intensity; and this same efficiency in ultra-thin films is higher than 90%. From these results, it was reported that the exciton migration radius in PFO is (13 ± 3) nm. Furthermore, effects of excitons annihilation in ultra-thin films were observed in the decay time radiative measurements due to high fluency (~ 10²⁵ photons/cm²s). Finally, in PFO films (with the β phase) deposited on the TiO₂ just the exciton of amorphous regions migrates to the TiO₂ interface, which dissociates them. The thermal energy at room temperature promotes higher efficiency than the exciton dissociation at low temperatures (~ 5 K). However, even at room temperature, the β phase molecules act as the most important molecules to capture exciton, competing to the exciton dissociation process. These results conducted to conclude that the energy transfer radius in PFO is equal to (3.5 + 0.5) nm.