Enhanced red-emitting by charge compensation in Eu3+-activated Ca2BO3Cl phosphors

Eu3+-activated Ca2BO3Cl with different charge compensation approaches were synthesized by the solid state reaction method, and systematically characterized by photoluminescence excitation and emission spectra, concentration quenching and CIE 1931 chromaticity coordinates at room temperature. All the samples show the characteristic red emission of Eu3+ ions with good CIE chromaticity coordinates. The relative emission intensities of Eu3+ (5D0→7F2) in Ca2BO3Cl:Eu3+ phosphors with Li, Na, K introduced as charge compensators are enhanced about 2.1, 1.6 and 1.5 times than that of direct charge balanced. Such difference is considered to be due to the different ion radii effect on the spin–orbit couplings and crystal field of Eu3+ ions. These results show that Ca2−1.5xBO3Cl:Eux3+ and Ca2−2xBO3Cl, Eux3+, Mx+ (x=0.04, M=Li, Na, K) phosphors exhibit potential applications in the field of solid state illumination.