A facile solution-phase approach to the synthesis of luminescent europium methacrylate nanowires and their thermal conversion into europium oxide nanotubes

Novel one-dimensional (1D) nanostructures of rare earth complexes (europium methacrylate (Eu(MA)₃)) have been prepared from the precursor of irregularly shaped Eu(MA)₃ powder in ethanol solvent without the assistance of an added surfactant, catalyst, or template. These hexagonal-shaped complex nanowires have diameters of about 100-300 nm and lengths ranging from tens to hundreds of micrometers. Nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) studies and thermogravimetric analysis (TGA) show that the precursor powder and the resulting nanowires have identical compositions. Under UV light excitation, strong red fluorescence can be clearly seen throughout the whole wires. This good luminescence characteristic of the complex nanowires is further confirmed by the fluorescence spectrum where strong and narrow emission can be seen. These rare earth complex nanowires provide a useful source for 1D rare earth oxide materials, as the europium ions are distributed uniformly in the Eu(MA)₃ nanowires. Through calcination, the Eu(MA)₃ nanowires are successfully converted into Eu ₂O₃ nanotubes. X-ray investigation confirms that the Eu₂O₃ nanotubes have a cubic body-centered structure. FTIR measurements and TGA analysis are used to follow the calcination process. A plausible mechanism responsible for the formation of Eu₂O₃ nanotubes is presented.