Tunable luminescence and energy transfer from Ce3+ to Dy3+ in Ca3Al2O6 host matrix prepared via a facile sol-gel process

Herein, Ce 3+ and Ce 3+ /Dy 3+ co-doped Ca 3 Al 2 O 6 phosphors have been designed and synthesized via a facile citrate-based sol-gel technique, and their structural, photoluminescence properties and energy transfer phenomenon were investigated comprehensively. The XRD analysis indicated that pure Ca 3 Al 2 O 6 phase can be synthesized at low temperature (1000 °C) for merely 2 h. The photoluminescence spectra showed the dominant emission of Ce 3+ singly doped phosphors is located in the blue region even at low Ce 3+ doping level, which indeed favors the energy transfer from Ce 3+ to other luminescent centers. When Dy 3+ is co-doped into Ca 3 Al 2 O 6 :Ce 3+ phosphors, the remarkable sensitizing effect of Ce 3+ on Dy 3+ is validated by comparatively analyzing the excitation, emission spectra and average lifetimes of the series of samples. Through the concentration quenching theory, the critical distance between Ce 3+ and Dy 3+ is calculated to be 13.50 Å. Furthermore, the energy transfer mechanism between them is most likely ascribed to electric dipole-dipole interaction. In virtue of the variation of the emission intensities of Ce 3+ and Dy 3+ , the emitting colors of Ca 3 Al 2 O 6 :Ce 3+ , Dy 3+ phosphors can realize tunable luminescence from deep blue to bluish-white region through controlling the Dy 3+ content. Based on these analysis, Ca 3 Al 2 O 6 :Ce 3+ , Dy 3+ phosphors could potentially be applied as a single-phase color-tunable phosphors pumped by near-ultraviolet (n-UV) radiation.