Photoluminescence Properties of Zirconia Nanobelts with Trace Sm3+ Ions

ZrO2 nanobelts have been prepared by a calcination route of ZrS3 nanobelts in air. They showed coexistence of tetragonal and monoclinic phases at 500-1000 degrees C. With the calcination temperatures increasing, tetragonal phase gradually changed into monoclinic phase. Up to 1100 degrees C the products were completely converted into monoclinic phase while the morphologies turned from regular nanobelts to bead-like nanowires. The optical band gaps of the nanobelts change from 4.46 eV to 3.54 eV with the temperatures rising from 500 to 1200 degrees C. Photoluminescence (PL) of ZrO2 nanobelts with traces of rare-earth ions was investigated. The emissions at 515 nm, and 549-950 nm under excitation of 325, 524, and 785 nm were assigned to combination-emissions of electrons and holes in oxygen vacancies in ZrO2 nanobelts, and f-f transitions of the Sm3+ ions (Sm: 0.00884 at.%), respectively. It is astonishing that such trace of Sm3+ ions can give rise to PL, and the phenomenon is reported at first time. The study is of practical meaning for knowing properties of Sm3+ ions and reasonably using the rare-earth elements in raw materials.