Size-dependent emission efficiency and luminescence characteristics of YBO3:Tb3+ nanocrystals under vacuum ultraviolet excitations.

The luminous efficiency and lifetime of plasma display panels (PDPs) are directly related to the performance of phosphors used in PDPs, thus higher efficiency, higher stability against high temperature processes, and a long lifetime along with good color chromaticity against vacuum-ultraviolet radiation are major concerns in selecting suitable phosphors for PDPs. In the same pursuit, well crystallized pure hexagonal phase YBO3:Tb3+ nanocrystals were prepared using co-precipitation method. The prepared YBO3:Tb3+ nanocrystals showed bright green luminescence, color chromaticity (0.21, 0.61), and could be assigned to 5D4→7Fj transitions (j = 2-6) due to electric dipole-dipole interaction of Tb3+ ions. The vacuum ultraviolet photoluminescence spectroscopy of the prepared YBO3:Tb3+ nanocrystals showed size dependent nonlinear luminescence enhancement with relatively shorter life time as compared to the commercial bulk YBO3:Tb3+ phosphor. The quenching concentration of Tb3+ doping for (5D4→7F5) transition was found significantly enhanced with the decrease in particle size suggesting it an ideal green phosphor for plasma display panels. The possible explanation for size-dependent emission efficiency and observed luminescence characteristics were proposed via charge transfer process and lowering of the structural symmetry. [ABSTRACT FROM AUTHOR]