Hafnium oxide films doped withCeCl3 and/orMnCl2, anddeposited at 300 °C by an ultrasonic spray pyrolysis process, were characterized using x-ray diffraction (XRD),energy-dispersive spectroscopy and photoluminescence. The XRD results revealedthat the films are predominantly amorphous. The weak green–red emission ofMn2+ is enhanced through an efficient energy transfer fromCe3+ toMn2+ ions. Spectroscopic data revealed that the energy transfer is nonradiative in nature and it could occurin Ce3+ and Mn2+ clusters through a short-range interaction mechanism. The efficiency of this transfer increases withthe Mn2+ ion concentration, so that an efficiency of about 78% is attained for a 5 at.% ofMnCl2 concentration, which makes these films interesting phosphors for the design of luminescentlayers with blue, green and red emissions.