Find in Library

Ce³⁺-doped and Ce³⁺/Mn²⁺ co-doped calcium carbodiimide (CaCN₂) phosphors were synthesized from doped calcium carbonate and carbon nitride by a solid-state reaction at 700 °C under flowing NH₃ using a very short reaction time (1 h). The samples were characterized by powder X-ray diffraction, scanning electron microscopy and their diffuse reflectance and luminescence properties were investigated. Single-doped CaCN₂:Ce³⁺ exhibits a blue emission under near-ultraviolet activation (386 nm) corresponding to the 5<i>d</i>¹ → ²F_5/2 and 5<i>d</i>¹ → ²F_7/2 transitions of Ce³⁺. Maximum emission is obtained at temperatures lower than 150 K and then progressively decreases up to 387 K, with an 80% drop in the emission at room temperature. Efficient energy transfers from Ce³⁺ to Mn²⁺ via a non-radiative dipole–dipole mechanism are evidenced for the co-doped samples, leading to various colored phosphors under near-ultraviolet activation (386 nm). The emission color of the obtained phosphors can be modulated from blue to red through a shade of white depending on the sensitizer/activator ratio.