Tuning Emission from Greenish to Blue via Chemical Composition Modulation in Solid Solutions (Sr1–yCay)₂Sb₂O₇:Bi³⁺ under near-UV Light Excitation

The Bi 3+ ion, with an exposed 6s 2 energy level sensitive for an external coordination environment, possesses complex and intriguing luminescent properties in various host lattices. Herein, we successfully prepared a new type of antimonate phosphor (Sr 1– y Ca y ) 2 Sb 2 O 7:Bi 3+ with controllable color emitting properties from greenish to blue stimulated by near-ultraviolet (UV) light. There are two emitting bands at 495 and 528 nm that go along with two crystallographic distinct Bi 3+ sites in the Sr 2 Sb 2 O 7 host. With increasing Ca constituents, enhancement of torsion resistance and the nephelauxetic effect would lead to the blue-shift of emitting bands. The internal quantum efficiency (IQE) of Sr 2 Sb 2 O 7:0.03 Bi 3+ and Ca 2 Sb 2 O 7:0.03 Bi 3+ was measured to be 51% and 62%, respectively. Finally, a white illuminating lamp was produced by using a 365 nm UV chip, blue phosphor Ca 2 Sb 2 O 7:0.03 Bi 3+, greenish phosphor Sr 2 Sb 2 O 7:0.03 Bi 3+, and red phosphor CaAlSiN 3:Eu 2+ . This work can provide design insights into turning the emitting colors of Bi 3+ doped phosphor by chemical composition modulation of the host lattice.