Photoluminescence and decay profiles of undoped and Fe3+, Eu3+-doped PLZT ceramics at low temperatures down to 10 K

Luminescence, time-resolved luminescence, excitation spectra and lifetimes of nominally pure and Eu, Fe-doped PLZT ceramics with perovskite A (Pb, La) B (Zr, Ti) O3 structure are investigated as a function of temperatures down to 10 K in order to elucidate luminescence centers in hot-/cold-pressed PLZT (9/65/35) and cold-pressed PLZT (8/70/30). At 10 K, the luminescence band of PLZT is considered to consist of two bands centered at 18 100 cm−1 (center 1) and 15 600 cm−1(center 2) with lifetimes of about τ1=1 ms and τ2=60 μs, respectively. Comparing luminescence, lifetimes and excitation spectral properties of various PLZT samples, center 1 can be assigned to octahedral [Ti(IV)O6] structures which are present in the cold-pressed, polycrystalline samples. Center 2 is identified as being due to oxo-coordinated octahedral Fe3+ ions associated with oxygen and lead-deficient octahedral [BO6−δ] (B=Ti4+, Zr4+) complexes in defect domains in the hot-pressed ceramics. Blue shift to 19 500 cm−1 and an abrupt shortening of lifetimes to 0.1 ms were observed at around 160 K due to the phase transition.