Photoluminescence, optical transmission and reflection of Alq₃ layers obtained by thermal evaporation deposition

In this paper we present the photoluminescence emission spectra (PL), photoluminescence excitation spectra (PLE), transmission (TS) and reflection (RS) spectra of tris(8-hydroxyquinoline) aluminum(III) (Alq₃) layers grown by thermal evaporation deposition method. All investigated samples exhibit strong luminescence in the wide temperature range from 13 K to room temperature and for different energies of excitation. In our experiments, we have focused on temperature dependence of photoluminescence. The thermal quenching of PL in the measured samples has been found. We have observed also distinct oscillations from reflection and transmission measurements. The energies of thermal activation estimated by means of configuration coordinate diagram and also the layer thickness and refractive index are presented.