Modulation of the Pr3+ Luminescence in the SrTi1_xZrxO3 Solid Solution

In this work ceramic samples of Sr0.9955Pr0.003Ti1-xZrxO3 (0.0 <= x <= 1.0)solid solution were synthesized by the Pechini method. Samples calcined at 800 degrees C for 1 h were characterized by X-ray diffraction; scanning electron microscopy, diffuse reflectance and photoluminescent spectroscopies. The compounds exhibit three different crystal perovskite-like structures as a function of the chemical composition: Cubic (0.0 <= x <= 0.2), tetragonal (0.3 <= x <= 0.6) and orthorhombic (0.7 <= x <= 1.0). The substitution of Ti4+ by Zr4+ in the solid solution results in an increase in the energy of the transition associated with the host. The presence of a ligand-to-metal charge transfer state between O2- and Ti4+ and its effect on the Pr3+ luminescence is shown. The photoluminescence response of Pr3+ is explained by using the chemical shift model. A remarkable consequence of the chemical variation in the series compounds, is the colormodulation of the emission under excitation at 447 nm ((3)H4 -> (3)P2). It goes from a dominant red emission ascribed to the (3)D2 -> (3)H4 transition to a dominant greenish-blue emission ascribed to the P-3(0) -> (3)H4. Finally, the color coordinates associated with the emission for the entire series are plotted in the CIE 1931 color space.