Luminescence properties of Eu3+ ions doped in novel host materials Sr9R(PO4)7 (R = In, Ga)

Novel Sr9R(PO4)7 (R = In, Ga) host materials for Eu3+ - doped phosphors were synthesized by a high-temperature solid-state reaction method. The crystal structure, luminescence properties and thermal stability of the phosphors were explored. The phase analysis indicated that the phosphors crystallized in monoclinic structure, the emission spectra of both In and Ga containing phosphors were mainly composed of two sharp peaks centered at about 591 and 617 nm, corresponding to the 5D0→7F1 and 5D0→7F2 transitions of Eu3+ ions. While, the relative emission and excitation intensities of Sr9In(PO4)7: Eu3+ were weaker than Sr9Ga(PO4)7: Eu3+. Moreover, the energy transfer mechanism among Eu3+ ions in the phosphors depended upon energy transfer among the nearest-neighbor ions described by the Dexter theory. The selected Sr9In(PO4)7: 0.06Eu3+ and Sr9Ga(PO4)7: 0.06Eu3+ exhibited high thermal stability and the chromaticity coordinate of the phosphors were located in the red-orange light region.