The structure and luminescence properties of green Ca3Al2O6:Bi3+ phosphors

A Ca3Al2O6:Bi3+ phosphor crystallized in space group Pa3¯ was prepared by conventional solid state reaction at 1300 °C. The scanning electron microscopy image indicates incorporated Bi3+ ions cannot only enhance the growth rate of Ca3Al2O6 crystal, but also change the growth interface of crystal. The phosphor has two prominent emission bands at 375 nm and 490 nm. When the phosphor is excited by the 285 nm light, the 490 nm emission band predominates. However, with the increase of excitation wavelength, the intensity of the 375 nm emission band enhances. The maximum intensity of the 375 nm emission band is at x = 0.01 in Ca3−xAl2O6:xBi3+ phosphor while that of the 490 nm emission band is at x = 0.03. There is an energy transfer process from the 375 nm emission to the 490 nm emission. Above experimental results indicate Bi3+ ions probably enter into different independent crystallographic sites of Ca2+ ions in the Ca3Al2O6 host lattice, and result in multiple luminescence centers. The Ca3Al2O6:Bi3+ phosphor can be a potential green phosphor for field emission display and white light-emitting diodes.

► A novel green Ca3Al2O6:Bi3+ phosphor was synthesized by solid state reaction.
► Multiple emission bands are attributed to six crystallographic independence sites for Bi3+ ions.
► The Stokes shift of 490 nm emission is longer than that of 375 nm emission.
► There is an energy transfer process from the 375 nm emission to the 490 nm emission.