Blue and red photoluminescence from Al₂O₃:Ce³⁺:Mn²⁺films deposited by spray pyrolysis

Abstract

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 most probable mechanism of energy transfer is found to be electric dipole–quadrupole interaction. The quantum efficiency of this transfer was estimated as being near to 100%, which makes these films interesting phosphors for the design of luminescent layers in flat-panel displays with two-colour emission.