Visible light-emission from Eu-doped ZnAl layered-double hydroxide

We report on the evolution of the emission and chemical properties of Eu-doped ZnAl-Layered double hydroxide (LDH) with variation of Eu doping concentration during the hydrothermal growth. With increasing Eu source concentration, the morphologies of the ZnAl-LDHs became denser and more closely packed while maintaining the thickness of each plate. As the Eu source concentration increased to 10 wt%, specific emission from the doped Eu3+ ions was enhanced in the photoluminescence spectra. However, the peak intensity decreased when the concentration increased further to 20 and 30 wt%. X-ray photoelectron spectroscopy results showed an abnormal increase of the Eu2+/Eu3+ ratio in the LDHs with increasing Eu source concentration, which suppressed the emission from the Eu3+ electronic transitions.