[Luminescence properties and spectral analysis of long phosphorescent phosphors: Ba(1 - x) Ca (x) Al2O4 : Eu2+, RE3+].

New long phosphorescent phosphors Ba(1 -x),Ca(x)Al2O4 : Eu2+, RE3+ (RE3+ = Dy3+, Nd3+) with tunable color emission have been prepared by solid state reaction. The luminescence properties of the samples are discussed and analyzed. The emission spectra show that the tuning range of the color emission of the phosphors is between 498 and 440 nm, which is determined by x, under the excitation of UV. The wavelength of afterglow increases with increasing x until x equals 0.6, and when x equals 0.6, the luminescence property of Ba(1-x) Ca(x)Al2O4: Eu2+, RE3+ (RE3+ = Dy3+, Nd3+) is similar to that of CaAl2O4 : Eu2+, RE3+. The XRD measurements were performed to investigate the single phase states of the samples, and it was found that the single phase limit in the phosphors is below an x value of 0.4. The thermoluminescence curves imply that the traps in the hosts are different with different x value, which well explains the varying delay time of the samples.