Studies on blue and red photoluminescence from Al2O3:Ce3+:Mn2+coatings synthesized by spray pyrolysis technique

Al2O3:Ce3+:Mn2+ 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 Ce3+ ions from their excited state 5d to the split ground state 2F. The usually weak red emission attributed to 3d→3d de-excitation of Mn2+ is enhanced through an efficient energy transfer from Ce3+ to Mn2+ 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 Al2O3 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.