Multi-color luminescence of uniform CdWO4 nanorods through Eu3+ ion doping

Abstract

Uniform Eu³⁺ doped CdWO₄ nanorods were prepared via a simple hydrothermal method and characterized by X-ray diffraction, transmission electron microscopy, photoluminescence (PL) spectroscopy and PL lifetime measurements. The results indicate that the obtained Eu³⁺ doped CdWO₄ nanorods have monoclinic phase structure, and the phase structure can be retained at Eu³⁺ doping concentrations of 0.4–4.0%. The diameter of nanorods decreases from 27 to 15 nm with an increase in the doping concentrations, and the morphology becomes irregular at the Eu³⁺ doping concentration of 6.5%. Under the excitation of ultraviolet light, the relative intensities of blue-green emission ascribed to WO₄²⁻ and red emission from Eu³⁺ can be tuned through doping Eu³⁺ ions into the CdWO₄ nanorods and thus altering the energy transfer between WO₄²⁻ and Eu³⁺. Hence, the multi-color luminescence in the same host at a single excited wavelength can be realized simply by altering the doping concentration of Eu³⁺. These luminescent nanomaterials may have potential applications in displays, light sources, bio-imaging and so on.