Emitting-Color Tunable Phosphors Sr₃GaO₄F:Ce³⁺ at Ultraviolet Light and Low-Voltage Electron Beam Excitation

Sr3−2xCexNaxGaO4F phosphors were prepared through a high-temperature solid-state reaction method. Their photoluminescence and cathodoluminescence properties were investigated. Under ultraviolet light and low-voltage electron beam excitation, the phosphors show a typical broad emission of Ce3+ and the luminescence color can be tuned in a large gamut from greenish-blue to yellowish-green by changing Ce3+ concentration in the range of 0.01−0.30 (x value). Their luminescence behaviors are discussed in terms of Ce3+ in two distinct sites. The lowest 5d absorption bands are respectively at ∼405 and ∼430 nm for Ce(1)3+ [i.e., Ce3+ in Sr(1)2+ site] and Ce(2)3+ [i.e., Ce3+ in Sr(2)2+ site] centers, while the emissions from relaxed 5d state to 2F5/2 ground state are respectively at ∼456 nm for Ce(1)3+ and ∼567 nm for Ce(2)3+.