The properties of the X films depend on the film thickness. For instance, the shape of the photoluminescence spectra of the X films is strongly related to the thickness of the semiconductor films, especially in the case of films thinner than 10 nm. Therefore, we have decided to investigate how the film thickness influences the spectroscopic and morphologic characteristics of the X films. It is worth noticing that X can exist as two different polymorphs named anti-anti-anti and syn-anti-syn. The former polymorph adopts a packing known as phase A, in which the molecules are piled in columnar stack. The latter polymorph adopts a packing known as phase B, in which the molecules adopt a brick wall arrangement. The photoluminescence spectra of phases A and B are markedly different from each other. According to what has been reported in the literature, only phase B is observed in films obtained by vacuum evaporation. Our preliminary results suggest that the properties of vacuum evaporated films are affected by the presence of micro-sized aggregates. Such aggregates can be observed both in AFM and confocal microscopies. Additional experiments must be performed to unravel the nature of these aggregates and to clarify their relation to the possible presence of phase A.