Luminescence properties and energy transfer investigations of Sr2B2O5:Ce3+,Tb3+ phosphors

Ce3+ and Tb3+ co-doped Sr2B2O5 phosphors were synthesized by the solid-state method. X-ray diffraction (XRD) was used to characterize the phase structure. The luminescent properties of Ce3+ and Tb3+ co-doped Sr2B2O5 phosphors were investigated by using the photoluminescence emission, excitation spectra and reflectance spectra, respectively. The excitation spectra indicate that this phosphor can be effectively excited by near ultraviolet (n-UV) light of 317 nm. Under the excitation of 317 nm, Sr2B2O5:Ce3+,Tb3+ phosphors exhibited blue emission corresponding to the f–d transition of Ce3+ ions and green emission bands corresponding to the f–f transition of Tb3+ ions, respectively. The Reflectance spectra of the Sr2B2O5:Ce3+,Tb3+ phosphors are noted that combine with Ce3+ and Tb3+ ion absorptions. Effective energy transfer occurred from Ce3+ to Tb3+ in Sr2B2O5 host due to the observed spectra overlap between the emission spectrum of Ce3+ ion and the excitation spectrum of Tb3+ ion. The energy transfer efficiency from Ce3+ ion to Tb3+ ion was also calculated to be 90%. The phosphor Sr2B2O5:Ce3+,Tb3+ could be considered as one of double emission phosphor for n-UV excited white light emitting diodes.