Effects of Eu3+ concentration and heat-treatment on photoluminescence properties of Zn1−xEuxAl2O4 phosphors

A series of Eu3+-doped ZnAl2O4 phosphors were synthesized by sol–gel method. The photoluminescence properties and morphology were systematically investigated. X-ray diffraction patterns indicated that pure spinel phase of high crystallinity can be obtained when the concentration of Eu3+ was less than 7 at.% with secondary calcination temperature in the range of 600–900 °C. The results of PL indicated that the emission spectra of Eu3+-doped ZnAl2O4 phosphors consist of five peaks located at 580, 593, 618, 653, 700 nm, which correspond to 5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3, 5D0 → 7F5 transitions, respectively. The luminescence intensity was significantly influenced by doping concentration and calcination temperature. The best Eu3+ concentration is 5 at.% and the best secondary calcination temperature is 800 °C. The phosphors can be efficiently excited under the excitation of 395 nm, indicating that Zn0.95Eu0.05Al2O4 can act as a potential near-UV LED-based red-emitting component for possible applications in solid-state lighting and display.