Preparation and research of nano-scale europium (III)-pyromellitic acid powder luminescent material.

The nanoscale luminescent complex of europium (III)-pyromellitic acid was synthesized successfully in the polyvinylpyrrolidone (PVP) matrix by a co-precipitation method. The chemical formula of the synthesized complex was speculated to be PVP/Eu4/3L x 3H2O by elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Fourier-transform infrared spectroscopy (FT-IR). The X-ray diffraction (XRD) pattern of PVP/Eu4/3L x 3H2O indicated that it was a new crystalline complex since the diffraction angle, diffraction intensity, and distance of the crystal plane were all different from those of the ligand. It is proved by the thermogravimetric curve that the synthesized nanoscale luminescent complex was stable, ranging from ambient temperature to 479 degrees C in air. The transmission electron microscopy (TEM) image showed that the complex was nanoparticles. The synthesized complex emitted the characteristic red fluorescence of Eu(III) ions under ultraviolet excitation by the photoluminescence analyses. For example, the emission peaks of PVP/Eu4/3L x 3H2O at 578, 591, 612, and 694 nm using 322 nm as exciting wavelength are assigned to the 5D0 --> 7F0, 5D0 --> 7F1, 5D0 --> F2, and 5D0 --> 7F4 electron transitions of the Eu3+ ions, respectively.