Blue-yellow photoluminescence from Ce 3+ → Dy 3+ energy transfer in HfO 2:Ce 3+:Dy 3+ films deposited by ultrasonic spray pyrolysis

Abstract

HfO 2 films codoped with Ce 3+ and several concentrations of Dy 3+ have been processed by the ultrasonic spray pyrolysis technique. Emissions from Dy 3+ ions centred at 480 and 575 nm associated with the 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 transitions, respectively, have been observed upon UV excitation via a non-radiative energy transfer from Ce 3+ to Dy 3+ ions. Such energy transfer via an electric dipole–quadrupole interaction appears to be the most probable transfer mechanism. The efficiency of this transfer increases up to 86 ± 3% for the film with the highest Dy 3+ content (1.9 ± 0.1 at.% as measured from EDS). The possibility of achieving the coordinates of ideal white light with increasing the concentration of dysprosium is demonstrated.