Red-emitting enhancement of Bi4Si3O12:Sm3+ phosphor by Pr3+ co-doping for White LEDs application

In this account, Bi4Si3O12:Sm3+ and (Bi4Si3O12:Sm3+, Pr3+) red phosphors were prepared by solution combustion method fueled by citric acid at 900 °C for 1 h. The effects of co-doping Pr3+ ions on red emission properties of Bi4Si3O12:Sm3+ phosphors, as well as the mechanism of interaction between Sm3+ and Pr3+ ions were investigated by various methods. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) revealed that smaller amounts of doped rare earth ions did not change the crystal structure and particle morphology of the phosphors. The photoluminescence spectroscopy (PL) indicated that shape and position of the emission peaks of (Bi4Si3O12:Sm3+, Pr3+) phosphors excited at λex=403 nm were similar to those of Bi4Si3O12:Sm3+ phosphors. The strongest emission peak was recorded at 607 nm, which was attributed to the 4G5/2→6H7/2 transition of the Sm3+ ion. The photoluminescence intensities of Bi4Si3O12:Sm3+ phosphors were significantly improved by co-doping with Pr3+ ions and were maximized at Sm3+ and Pr3+ ions doping concentrations of 4 mol% and 0.1 mol%, respectively. The characteristic peaks of Sm3+ ions were displayed in the emission spectra of (Bi4Si3O12:Sm3+, Pr3+) phosphors excited at respectively λex=443 nm and λex=481 nm (Pr:3H4→3P2, 3H4→3P0). This indicated the existence of Pr3+→Sm3+ energy transfer in (Bi4Si3O12:Sm3+, Pr3+) phosphors.