Colour tuning and energy transfer pathways in MgAl₂O₄ triply doped with 0.1% Ce³⁺, 0.1% Eu²⁺, x% Tb³⁺ (0⩽x⩽2%) nanocrystals synthesized using sol-gel process

A series of the undoped, 0.1% Ce³⁺, 0.1% Eu²⁺, 0.1% Tb³⁺ singly doped and 0.1% Ce³⁺, 0.1% Eu²⁺, x% Tb³⁺ (0⩽x⩽2%) triply doped MgAl₂O₄ nanophosphors were synthesized by the sol-gel technique and thereafter annealed at 800 °C. The nanocrystals consist of the pure cubic structures. The type of the dopant and varying the Tb³⁺ mol% influence the crystallites size and morphology of the prepared powders. Photoluminescence (PL) results showed a red emission from Ce³⁺ singly doped MgAl₂O₄. Furthermore, the PL results revealed the existence of the energy transfer from Eu²⁺ → Tb³⁺ → Ce³⁺. CIE colour chromaticity showed that the colour can be tuned from bluish → greenish by changing the Tb³⁺ mol% and the excitation wavelength.