Rapid Synthesis and Photoluminescence Properties of Eu-doped ZnO Nanoneedles via Facile Hydrothermal Method

Eu-doped ZnO nanoneedles with different doping concentrations were prepared via the facile hydrothermal method. The crystal structure, morphology and photoluminescence property of the ZnO nanoneedles were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), photoluminescence spectroscopy(PL) and Raman spectroscopy. The results show that the europium ions are incorporated into the crystal lattice of ZnO matrix in trivalent ions. The nanoneedles are 2-3 μm in length and 100 nm in the tip diameter. PL and Raman measurements indicate that higher Eu³⁺ doping concentration may destroy the crystallization of the nanoneedles and decrease the ratio of I_UV/I_DLE, which is mainly due to the more defects in the doped ZnO nanoneedles. And the characteristic red emissions of Eu³⁺ ions are found by the PL spectroscopy with the Eu³⁺ doping concentration increasing, which are attributed to the ⁵D₀→⁷F₀, ⁵D₀→<⁷F₁ and ⁵D₀→⁷F₂ transitions.