(Ba,Sr)TiO:RE perovskite phosphors (RE = Dy, Eu): nitrate pyrolysis synthesis, enhanced photoluminescence, and reversible emission against heating.

A series of (Ba,Sr)TiO phosphors singly doped with Eu and Dy were successfully synthesized using the nitrate pyrolysis method at 750 °C. Eu or Dy single-doped BaTiO retained the tetragonal crystal structure of the host, while the Sr-substituted (Ba,Sr)TiO:RE (RE = Eu or Dy) experienced a phase transformation from tetragonal to cubic phase with a unit cell shrinkage. For Eu doped phosphors, BaTiO:Eu ( = 0.02-0.10) exhibited red photoluminescence and the highest intensity of emission belonged to the optimal-doped BaTiO:Eu ( = 8 mol%). Moreover, the substitution of 30 mol% Sr for Ba (that is BaSrTiO:Eu, = 8 mol%) further enhanced the emission intensity of BaTiO:Eu ( = 8 mol%). For Dy doped phosphors, BaTiO:Dy ( = 0.02-0.10) showed yellow photoluminescence and the highest light intensity was from the optimal-doped BaTiO:Dy ( = 4 mol%). In addition, the substitution of 20 mol% Sr for Ba (the phosphor BaSrTiO:Dy, = 4 mol%) induced further increase in emission intensity of BaTiO:Dy ( = 4 mol%). The emission intensities at higher temperature of 100 °C retained about 70% and 90% of the initial values at room temperature (RT) for the optimal BaTiO:Eu ( = 8 mol%) and BaTiO:Dy ( = 4 mol%) phosphors, respectively, while the emission intensities at the temperature of 100 °C retained about 60% and 80% of the initial intensities at RT for the optimal Sr-substituted BaSrTiO:Eu ( = 8 mol%) and BaSrTiO:Dy ( = 4 mol%) phosphors, respectively. It is worth noting that on cooling down to RT again from 210 °C, the BaTiO:Dy ( = 4 mol%) phosphor exhibited excellent luminescent thermal stability (with a high activation energy of 0.387 eV) and the strongest recovery (∼95%) of PL emission among the series of phosphors. The as-prepared phosphors with optimal compositions would be good candidates for the applications in lighting, display, and related fields.