Luminescence and energy transfer of a novel tunable-emitting phosphor Sr0.8Ca0.2Al2Si2O8:Eu/Tb for white LEDs

A series of Sr0.8Ca0.2Al2Si2O8:Eu/Tb are synthesized, and the luminescence property and energy transfer of Eu2+, Tb3+, Eu3+ are explored. The results indicate that Sr0.8Ca0.2Al2Si2O8:Tb3+ presents the typical green emission, however, Eu2+ and Eu3+ coexist when Sr0.8Ca0.2Al2Si2O8:Eu is synthesized under air atmosphere. There is no the characteristic emission of Tb3+ in the emission spectra of Sr0.8Ca0.2Al2Si2O8:Eu, Tb synthesized in the atmosphere, but the emission spectra of Tb3+ appeared in the emission spectra of Sr0.8Ca0.2Al2Si2O8:Eu, Tb synthesized in the reducing condition. It may be deuced by the two forms of energy transfer: Eu2+→Tb3+ and Tb3+→Eu3+. And the energy transfer efficiency of Tb3+→Eu3+ is much greater than that of Eu2+→Tb3+. When Eu2+, Tb3+ and Eu3+ exist at the same time, there is the energy transfer of Eu2+→Tb3+→Eu3+. This result is of great significance for changing the luminescent properties of phosphors based on energy transfer.