The VUV–vis luminescent properties of Ln3+ (Ln = Ce, Pr, Tb) in Sr0.96Na0.02Ln0.02B4O7

The spectroscopic properties of Ce3+, Pr3+ and Tb3+ activated SrB4O7 in VUV–vis range were investigated. The split 5d levels for Ce3+ in the host lattice are discussed and an environmental factor Fc is used to explain the crystal field splitting (CFS). The photon cascade emission (PCE) process was observed in Pr3+ doped SrB4O7, and the quantum efficiency of PCE is estimated. An empirical relationship between the lowest spin-allowed f–d transition energy [Wfd(n)] and n-value for 4fn-series Ln3+ (Ln = Ce, Pr, Tb) ions in SrB4O7 is proposed.