Comparative investigation on luminescence properties of Mn4+ doped Ba6Y2W3O18 and Ba6Gd2W3O18 phosphors

Mn4+ doped Ba6Y2W3O18 and Ba6Gd2W3O18 phosphors of double perovskite structure have been synthesized via solid-state reaction method at high-temperature. Excitation spectra show the phosphors have broad excitation band in region of 300 - 600 nm with four Gaussian fitting bands peaking at around 331 nm, 366 nm, 440 nm and 518 nm for Ba6Y2W3O18:Mn4+ and peaking at around 347 nm, 374 nm, 436 rim and 511 rim for Ba6Gd2W3O18:Mn4+. Far-red emission band locates at 693 nm for Ba6Y2W3O13:Mn4+ and at 676 nm for Ba6Gd2W3O13:Mn4+, respectively. The Maximum IQC is as high as 59.82 % for Ba6Y2W3O18:Mn4+ and 58.68 % for Ba6Gd2W3O18:Mn4+. The difference of the crystal field strength and nephelauxetic effect of Mn4+ ion in Ba6Y2W3O18 and Ba6Gd2W3O18 matrix are also discussed. The substitution between Y3+ and Gd3+ induced variation of luminescence properties might give meaningful reference for designing new Mn4+-doped phosphor or regulating its luminescence performance.