Luminescence self-quenching in praseodymium-doped double sodium-yttrium fluoride cubic crystals (Na0.4Y0.6F2.2:Pr3+)

Energy transfer processes between praseodymium dopant ions, which are responsible for the luminescence self-quenching in crystals Na0.4Y0.6F2.2:Pr3+ (NYF:Pr3+; Pr = 0.4-9%), have been investigated experimentally and theoretically. Using methods of kinetic spectroscopy with selective excitation, the praseodymium luminescence decay kinetics from the levels (3) P (0,1) and (1) D (2) selectively excited by nanosecond laser pulses has been studied. Based on model quantum-mechanical calculations, interionic interaction microparameters have been determined theoretically and mechanisms that are responsible for the interaction of praseodymium ions by particular most likely energy transfer schemes have been elucidated. Energy transfer macrorates (of migration and quenching) have been found, and the values obtained have been used as parameters for calculation of the decay dynamics of the excited (1) D (2) and (3) P (0,1) levels of praseodymium ions. It has been shown that luminescence self-quenching from the (1) D (2) level in NYF:Pr3+ crystals can be described well in terms of the model of static ordered decay in the presence of dipole-dipole and dipole-quadrupole interactions. The luminescence self-quenching from the (3) P (0,1) levels is mainly determined by the dipole-dipole interaction, and it also can be described in terms of the model of the static ordered decay. Good agreement has been obtained between experimental and calculated kinetic dependences that characterize energy transfer processes in NYF:Pr3+ crystals in relation to the concentration of doping ions. Based on the obtained data, it has been concluded that investigated crystals of a certain composition are promising for use in quantum electronics and optical converters.