Yttrium Oxide Upconverting Phosphors. Part 2: Temperature Dependent Upconversion Luminescence Properties of Erbium in Yttrium Oxide

摘要

Emission bands from Er~(3+) ions on C_2 and S_6 sites of cubic Y_2O_3 have been observed under 632.8 nm excitation. The well-known green hot band in the region of 520-540 nm and a new blue-gren hot band in the region of 469-474 nm have been observed from Er~(3+) on both sites. These hot bands are assigned to the ~2H_(11/2) -> ~4I_(15/2) and the ~4F_(3/2) -> ~4I_(15/2) transitions, respectively. In addition to observing different thermal behavior for the emissions from Er~(3+) ions on different lattice sites due to these transitions, different thermal behavior has also been observed for the ~4F_(5/2) -> ~4I_(15/2), ~4F_(9/2) -> ~4_(15/2), ~4S_(3/2) -> ~4I_(15/2), and ~4I_(11/2) -> ~4I_(15/2) transitions. The ~4G_(11/2) -> ~4I_(15/2), ~2H_(9/2) -> ~4I_(15/2), and ~4I_(9/2) -> ~4I_(15/2) transitions gave rise to bands which were too weak for accurate temperaturedependent studies. Emission arising from the ~4F_(7/2) -> ~4I_(15/2) transition was observed with 514.5 but not 632.8 nm excitation.