Color tunable emission in Ce3+ and Tb3+ co-doped Ba2Ln(BO3)2Cl (Ln = Gd and Y) phosphors for white light-emitting diodes

PL spectra of (a) Ba2Y(BO3)2Cl:0.03Ce3+, mTb3+, (b) Ba2Gd(BO3)2Cl:0.01Ce3+, nTb3+ with different Tb3+ contents and (c) the corresponding energy-level diagram. Insets: Dependence of PL intensity of Ce3+ and Tb3+ on the concentrations of Tb3+.