Photoluminescence and photocatalytic properties of Eu³⁺-doped ZnO nanoparticles synthesized by the nitrate-citrate gel combustion method

Abstract.

A series of Eu³⁺-doped ZnO nanoparticles were synthesized by the nitrate-citrate gel combustion method. Rietveld refinement results verified that the compounds were crystallized in the wurtzite hexagonal structure with space group P63mc (No. 186). Field emission scanning electron microscopy micrographs show porous morphology. Transmission electron microscopy analysis revealed that the particles are in the range of 35-40 nm. The photoluminescence spectra of ZnO nanocrystallites exhibit a broad intense peak at 506nm and a weak emission peak at 379 nm under UV excitation. The characteristic emission peaks were observed at 592 and 612 nm due to the ⁵ D ₀ $\rightarrow$ ⁷ F ₁ and ⁵ D ₀ $\rightarrow$ ⁷ F ₂ transitions of the Eu³⁺ ion. The photocatalytic degradation of methylene blue dye increases with increase in Eu³⁺ ion concentration. 5 mol% Eu³⁺-doped ZnO nanoparticles showed 100% dye degradation within 150 min. The present work can be useful for display devices and environmental remedy applications.