Up-conversion luminescence of BaCl2:Er3+ nanocrystals embedded in oxychloride nano-glass ceramic

A novel glassy nanocomposite containing Er3+-doped BaCl2 nanocrystals of about tens of nm embedded in a silicate matrix has been prepared by using sol-gel route followed by controlled crystallization of the xerogel. Under 810 nm laser light pumping it shows green ((2H11/2, 4S3/2) → 4I15/2) and red (4F9/2 → 4I15/2) up-conversion luminescences ascribed by a two-photon processes. The luminescence signal recorded in the oxychloride nano-glass ceramic is only about 10% compared to the NaYF4:Er3+ (18%). In the nano-glass ceramic there are effective non-radiative decay channels, most probably related to hydroxyl ions and surface defects acting as centers for the non-radiatively energy dissipation.