Photoluminescence and energy transfer of YAG: Ce3+, Gd3+, Bi3+

Abstract

In this study, Gd[Formula: see text] and Bi[Formula: see text] ions act to redshift the emission band to orange region, and to enhance significantly the maximum emission of YAG: Ce[Formula: see text]. On account that size mismatch between the host and the doped Gd[Formula: see text] ion, the crystal structure turns soft, and the emission spectra are not tuned from 540 to 570[Formula: see text]nm but decreased the emission intensity. Accordingly, an effective way to increase emission intensity is to introduce Bi[Formula: see text] ion into the YAG: Ce[Formula: see text], Gd[Formula: see text] phosphors. Experimental results show partial overlapping between the emission band of Bi[Formula: see text] ion and the excitation band of Ce[Formula: see text] ion, indicating that the energy transfer from Bi[Formula: see text] to Ce[Formula: see text] ions exists in the (Y[Formula: see text]Ce[Formula: see text]Gd)Al5O[Formula: see text]: Bi[Formula: see text] phosphor. Bi[Formula: see text] ion can serve as the activator to provide energy for Ce[Formula: see text] ion via cross relaxation phenomenon. Therefore, the (Y[Formula: see text]Ce[Formula: see text]Gd)Al5O[Formula: see text]: Bi[Formula: see text] phosphor could have potential applications in warm white LEDs.