Luminescence and energy transfer mechanism of KZnPO4: Dy3+, Eu3+

Dy3+ -doped and Dy3+/Eu3+ co-doped KZnPO4 phosphors have been successfully synthesized by solid-state method. X-ray diffraction (XRD), photoluminescence spectra and fluorescence lifetime are employed to characterize these samples. It can be indicated from XRD results that KZnPO4 phosphors exhibit pure phase with high crystallinity. Under excitation of 391nm, Dy3+-doped KZnPO4 phosphors showed two typical emission bands at 485nm (blue) and 577nm (yellow). In the case of Dy3+ and Eu3+ co-doped KZnPO4 phosphors, it can be found that color coordinates are sensitive to the Eu3+ concentration due to the red emission from Eu3+ ions. The emission color changes from blue to warm white by increasing the Eu3+ contents. The color coordinates and color temperature were also adjusted by changing the contents of Eu3+ ions. Furthermore, the mechanism of energy transfer from Dy3+ to Eu3+ ions is demonstrated to be quadrupole-quadrupole interaction for the co-doped samples.