LaGaO₃:A (A = Sm³⁺and/or Tb³⁺) as promising phosphors for field emission displays

LaGaO3:Sm3+, LaGaO3:Tb3+ and LaGaO3:Sm3+,Tb3+ phosphors were prepared through a Pechini-type sol–gel process. X-Ray diffraction, field emission scanning electron microscopy, photoluminescence (PL), and cathodoluminescence (CL) spectroscopy were utilized to characterize the synthesized phosphors. Under excitation with ultraviolet light (250–254 nm), the LaGaO3:Sm3+, LaGaO3:Tb3+ and LaGaO3:Sm3+,Tb3+ phosphors mainly show the characteristic broadband emission (from 300 to 600 nm with a maximum around 430 nm) of the LaGaO3host lattice, accompanied by the weak emission of Sm3+ (4G5/2 → 6H5/2, 6H7/2, 6H9/2 transitions) and/or Tb3+ (5D3,4 → 7F6,5,4,3 transitions). However, under excitation by low-voltage electron beams (1–3 kV), the LaGaO3:Sm3+, LaGaO3:Tb3+ and LaGaO3:Sm3+,Tb3+ phosphors exhibit exclusively the characteristic emissions of Sm3+ and/or Tb3+ with yellow (Sm3+), blue (Tb3+, with low concentrations) and white (Sm3+ + Tb3+) colors, respectively. The CL intensities (brightness) of the LaGaO3:Sm3+ and LaGaO3:Tb3+ phosphors are higher than those of the commercial products (Zn, Cd)S:Ag+ (yellow) and Y2SiO5:Ce3+ (blue), respectively. Related luminescence mechanisms are proposed to explain the observed phenomena.