Photoluminescence properties and energy level of RE (RE = Pr, Sm, Tb, Er, Dy) in Y4Si2O7N2

RE3+ (RE = Pr, Sm, Tb, Er, Dy)-activated Y4Si2O7N2 samples were prepared by a solid-state reaction method at high temperature, and their photoluminescence properties were investigated. The absorption band located at about 250 nm is attributed to the host absorption. The 5d bands of Pr3+ and Tb3+ are at rather low energy in Y4Si2O7N2 compared to oxide. The direct Pr3+ 4f 2 → 4f 15d 1 excitation at 275 nm leads to typical 4f 2 → 4f 2 line …