Solid solutions of (Ba1-XSrX)4Al 2S7 (X = 0.2 to 0.6) novel thioaluminate compound were synthesized, whose crystal structure was determined. The crystal structure of the (Ba1-XSrX)4Al2S7 solid solution is related to that of monoclinic Ba4Ga 2S7 consisting of isolated Ga2S7 units. However, the local structures around Ba/Sr in (Ba1-XSr X)4Al2S7, such as coordination number and one unusually long bond (d(Ba,Sr)-S 4 Å) in 7- and 8-coordinated (Ba,Sr)-S, are different from those in Ba4Ga 2S7. Eu2+-activated (Ba1-XSr X)4Al2S7 exhibited orange emission with a peak maximum at 594 nm and a corresponding excitation band at 300 to 550 nm. This is the first report of an orange phosphor in the thioaluminate system. The thermal quenching of luminescence in the (Ba1-XSr X)4Al2S7:Eu2+ phosphor was comparable to that in a conventional Y3Al5O 12:Ce3+ phosphor.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials