Ion implantation into (111) PZT films was done with 150 keV O+-ions using the following doses: 5 · 1010cm−2and 5 · 1013cm−2. The penetration depth of the O+-ion beam (through a 150 nm top Pt-electrode) was calculated with the TRIM. SP program version TRVMC95. For 104particles, 22% of them were calculated to pass the top Pt electrode, 1% of the 104particles were calculated to reach a penetration depth of 150 nm in PZT. The O+-implantation led to a significant improvement (50%) of loss factortanδ. This effect is ascribed within current theory to a decrease of oxygen vacancies (defects). Oxygen vacancies are supposed to be associated by Ti3+, Ti2+and Ti+centers in the perovskite lattice. Evidence for a possible participation of such reduced (charged) titanium defects was obtained by luminescence spectroscopy. Therefore, PZT samples were treated with H2to increase the concentration of reduced Tin+(n<4) ions in the perovskite lattice by chemical treatment. The luminescence spectrum of such reduced samples showed peaks at 3.2, 2.95 and 2.8 eV (surface Ti3+, Ti2+Ti+centers). Furthermore, peaks at 1.87eV and 2.2 eV were observed. These near-midgap states have been ascribed to transitions from Ti3+and Ti2+from the bulk of PZT (3.8 eV excitation energy, T = 6K). Finally, a sharp luminescence peak at 3.34 eV (6K) is assigned as self-trapped exciton luminescence.