부산대학교 도서관

Luminescence properties of a palmierite-type K5Eu(MoO4)4 crystal were studied in a wide temperature range of 7-650 K. Eu3+ ions are shown to occupy at least three non-equivalent positions in the palmierite-type structure, forming emission centres with slightly different characteristics due to an incommensurate modulated disordering. The relative intensity of the Eu3+ emission bands originating from the 5D0 and 5D1 terms is shown to depend on excitation energy and the origin of the observed differences is discussed. It is shown that quenching temperature of the Eu3+ emission depends on excitation energy that is explained by energetical overlap of the 4f-4f Eu3+ transitions with the Urbach tail of the fundamental absorption region. Energy transfer processes to the Eu3+ emission centres were studied using the methods of time resolved spectroscopy.