Luminescence measurements on Sm2+-doped sol–gel glasses

Sol-gel glass samples containing nominally 1, 2, 5, and 10 wt% Sm 2 O 3 doped into the molar compositions 5Na 2 O-10Al 2 O 3 -85SiO 2 and 10Al 2 O 3 -90SiO 2 were prepared from metal alkoxide solution. After heat treatment in air at 500 °C, the samples were heated at 750 °C under flowing H 2 or at 800 °C under a flowing H 2 /N 2 to reduce Sm 3+ to Sm 2+ , Samarium ions in the divalent and trivalent states were identified by luminescence and lifetime measurements. Samples incorporated with Sm 2+ showed emission with peaks at 683, 700, 725 and 763 nm due to transitions 5 D 0 → 7 F 0.12 3 , respectively, of Sm 2+ ions. The luminescence properties of Sm 2+ ions are discussed in relation to the concentration of Sm 2 O 3 and the glass matrix composition. The relative proportion of Sm 2+ decreases with increasing Sm 2 O 3 doping concentration. Preliminary high pressure luminescence results for Sm 2+ in the glasses show a complete quenching of Sm 2 luminescence and an irreversible local modification in the glass network.