Optical properties and local structure of Eu3+-doped synthetic analogue of the microporous titanosilicate mineral sitinakite

The synthetic analogue of the microporous titanosilicate mineral sitinakite has been hydrothermally synthesized and used as a host in the preparation of a new photoluminescent material. The inclusion of Eu3+ in the pores of the sitinakite doubles the unit cell volume and changes the symmetry of the initial sodium phase. The Eu3+-doped material displays a stable room temperature emission ascribed to the Eu3+ intra-4f6 5D0→7F0−4 transitions, with a maximum external quantum yield of 6%. The observation of two components for the non-degenerated 5D0→7F0 transition, the local field splitting of the 5D0→7F1−2 transitions, and the 5D0 emission decay curves point out the presence of two optically active Eu3+ sites. Possible structural distribution of the detected Eu3+ cations is discussed.