Studies on blue and red photoluminescence from Al 2O 3:Ce 3+:Mn 2+coatings synthesized by spray pyrolysis technique

Abstract

Al 2O 3:Ce 3+:Mn 2+ films deposited by the spray pyrolysis technique show blue and red emissions under ultraviolet light excitation. The blue emission is due to the de-excitation of Ce 3+ ions from their excited state 5d to the split ground state 2F. The usually weak red emission attributed to 3d→3d de-excitation of Mn 2+ is enhanced through an efficient energy transfer from Ce 3+ to Mn 2+ ions. The quantum efficiency of this transfer is near to 100%. SEM and RBS have been used to analyze the surface morphology and chemical composition of Ce- and Mn-doped Al 2O 3 films. The films were also characterized by the X-ray photoelectron spectroscopy technique, and it was found that a considerable amount of Mn ions remains linked to chlorine while Ce is mostly in an oxidized state.