Enhancement of green emission by the codoping A+ (A = Li, Na, K) in Ca2BO3Cl:Tb3+ phosphor

Abstract

Tb3+-doped Ca2BO3Cl compounds with different charge compensation approaches are synthesized by a high-temperature solid-state reaction method, and the luminescent properties and Commission Internationale de l'Eclairage (CIE) chromaticity coordinates are systematically characterized. Ca2BO3Cl:Tb3+ can produce green emission under 376 nm radiation excitation. With codoped A+ (A = Li, Na, K) as charge compensators, the relative emission intensities of Ca2BO3Cl:Tb3+ are enhanced by about 1.61, 1.97, and 1.81 times compared with those of the direct charge balance, which is considered to be due to the effect of the difference in ion radius on the crystal field. The CIE chromaticity coordinates of Ca2BO3Cl:Tb3+, A+ (A = Li, Na, K) are (0.335, 0.584), (0.335, 0.585), and (0.335, 0.585), corresponding to the hues of green. Therefore, A+ (A = Li, Na, K) may be the optimal charge compensator for Ca2BO3Cl:Tb3+.