Emission properties of (SrTiO3–TiO2):Pr3+ eutectic with self-organized fractal microstructure

Abstract An investigation of spectroscopic properties of (SrTiO 3 –TiO 2 ):Pr 3+ eutectic and, for comparison, of bulk SrTiO 3 :Pr 3+ and TiO 2 :Pr 3+ crystals is presented. Luminescence spectra have been measured under both 450 nm and 350 nm excitation wavelength. For UV excitation they are characterized by a dominant red luminescence corresponding to transition from the 1 D 2 level of Pr 3+ ions. The mechanism responsible for quenching of blue (from 3 P 0 state) and intensification of red luminescence is proposed to be thermally-induced radiationless relaxation involving a low-lying Pr 3+ –Ti 4+ intervalence charge transfer state. Measured decay constants of 1 D 2 excited state of Pr 3+ are compared with values obtained for other praseodymium doped titanate hosts.