关键词: Ca2SnO4:Eu3+, 反应机理, 光致发光, 掺杂浓度

Abstract: Eu³⁺ doped Ca₂SnO₄ powder samples were prepared by a solid-state method and their formation mechanism and luminescent properties were investigated. When the starting powder mixture of CaCO₃ and SnO₂ (2:1) is calcined at 1250℃, the unstable intermediate phase CaSnO₃ is developed, which then reacts with CaO to form the final product Ca₂SnO₄. The excitation spectra of Ca _2-xEu_xSnO₄ show broad Eu ³⁺-O^2- charge-transfer bands with the peak locations changing from 274nm to 292nm by increasing Eu³⁺ concentrations (x=0.01--0.15). Under UV excitation, the Ca₂SnO₄:Eu³⁺ phosphor exhibits novel red emission at about 618nm which is assigned to the ²D-⁷F₂ electric-dipole transition. In addition, the weak emission transitions from the higher ⁵D₂ and ⁵D₁ excited states can be observed at low Eu³⁺ concentrations because of the low multiphonon relaxation probability. The spectral shape of the Eu³⁺ emission of Ca₂SnO₄:Eu³⁺ is similar to that of its isostructural compound Sr₂CeO₄ :Eu³⁺ , however, the red emission from the former is much stronger than that from the latter.

Key words: Ca2SnO4:Eu3+, formation mechanism, photoluminescence, doping concentration