Luminescence properties of CsPrP4O12 and RbPrP4O12

Single crystals of CsPrP4O12 and RbPrP4O12 cyclotetraphosphates have been grown using the flux method. Selective excitations in the Pr3+ (4f2) 3P0 and 3P2 levels using an excimer-pumped dye laser mainly result in intense line emissions in both materials. Although originating from transitions within the Pr3+ 4f2 ground configuration, these emissions have very short decay times, of the order of 50 ns. Both compounds also exhibit intense ultraviolet band emissions in the 200–300 nm spectral range when using either a xenon lamp or an X-ray source for optical excitation. The decays of these emissions under pulsed X-ray excitation were measured using the start–stop technique. They exhibit a main fast component (decay time τf) and a minor slower one (decay time τs), the decay times of which are τf≅9 and 5 ns, τs≅30 and 20 ns, in the Cs and Rb compounds, respectively.