Near-Infrared Emission in Na₅Y(WO₄)₄:Nd³⁺

Luminescence in Na₅Y(WO₄)₄:Nd³⁺ is investigated for the first time. The emission is in the near-infrared region. The well known ⁴F_3/2 → ⁴I_9/2 transition leads to most intense line at 1069 nm. The excitation and emission spectra are interpreted using the energy level diagram of Nd³⁺. The excitation spectrum is made up of a large number of sharp lines attributable to various f–f transitions. A weak band at 360 nm in the ex-citation spectrum is assigned to the host. Notwithstanding large Y–Y distances, the luminescence is quenched at concentrations exceeding 2 mol %. The critical distance for energy transfer among Nd³⁺ ions is found to be 32.85 Å.