Photoluminescence and time resolved photoluminescence spectra of Ca(NbO3)(2) doped with Pr3+, excited under 37,000 cm(-1) (270 nm), obtained at high hydrostatic pressure up to 20 kbar applied in a sapphire anvil cells, are presented. At ambient conditions, the emission spectrum obtained in the time interval 0-1 is is dominated by spin allowed transitions from the P-3(0) state. The luminescence related to transitions from D-1(2), characterized by a decay time equal to 33 mu s, is observed when one excites directly the Pr3+ ion with 30,770 cm(-1) (325 nm) wavelength. The introduction of Pr3+ impurities in Ca(NbO3)(2) does not quench the self-trapped exciton (STE) luminescence. This luminescence, peaking at 20,000 cm(-1) (500 nm), having a decay time of 61 +/- 1 mu s, still occurs when the crystal is excited with a wavelength of 37,000 cm(-1) (270 nm) or shorter. Under such excitation a fraction of the STE luminescence is reabsorbed by Pr3+ ions; in this case the emission lifetime of the D-1(2) -> H-3(4) transition of Pr3+ is 64 +/- 3 mu s. This effect is stable also at high pressure. (C) 2010 Elsevier Ltd. All rights reserved.
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