Blue-yellow photoluminescence from Ce3+ → Dy3+ energy transfer in HfO2:Ce3+:Dy3+ films deposited by ultrasonic spray pyrolysis

Research highlights: → A blue-yellow emission phosphor excited with UV radiation can be manufactured with CeCl3 and DyCl3 doped HfO2 films deposited at 300 deg. C by the ultrasonic spray pyrolysis technique. → The addition of DyCl3 in the HfO2:CeCl3 film leads to a non-radiative energy transfer from Ce3+ to Dy3+ under Ce3+ excitation at 280 nm. → The efficiency of this transfer increases up to 86 ± 3% for the film with the highest Dy3+ content. → The possibility of achieving the coordinates of ideal white light with increasing the concentration of dysprosium is demonstrated. - Abstract: HfO2 films codoped with Ce3+ and several concentrations of Dy3+ have been processed by the ultrasonic spray pyrolysis technique. Emissions from Dy3+ ions centred at 480 and 575 nm associated with the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions, respectively, have been observed upon UV excitation via a non-radiative energy transfer from Ce3+ to Dy3+ 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 Dy3+ 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.