Synthesis and luminescence properties of BaHfO3: Pr ceramics

BaHfO3 sintered ceramic scintillators doped with various Pr concentrations (0-1 mol%) were synthesized at 1700 °C in N2-H2 atmosphere. XRD, SEM and photo-luminescent techniques at various temperatures (40 K to 550 K) were employed to reveal properties of the BaHfO3:Pr ceramics. Results of spectroscopic investigation indicate that the luminescence is connected almost exclusively with decay of the 3P0 level, while the emission from 1D2 is hardly seen even for higher Pr3+ concentrations. However, the intrinsic emission of BaHfO3 matrix, related with defects or impurities, seems to compete with the emission of Pr3+ ions. The 3P0 luminescence decays give time constant of about 25-32 μs in the 40-550 K range of temperatures, while the 1D2 decay time depends on the dopant concentration and gets shorter above 300 K for 1% specimen due to a cross relaxation process between Pr3+ ions.