Luminescent properties and energy transfer of Gd3+/Eu3+ co-doped high uniform meso-silica nanorods

Eu3+ and Gd3+ ions co-doped amorphous silica nanorods were prepared using a simple sol-gel method, and their luminescent properties were studied under the excitation of ultraviolet light. X-ray diffraction (XRD), Energy-dispersive X-ray (EDX) spectroscopy, Fourier transform infrared spectrum (FT-IR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), and Photoluminescence (PL) spectra were employed to characterize the products in detail. The nanorods are uniform and their diameters and lengths are in the range of 200-300 nm and 500-700 nm, respectively. Energy transfer process in Gd3+ and Eu3+ co-doped silica, where a ground state of Gd3+, 8S7/2, was selectively excited to a 6IJ state under the excitation of 274 nm, was studied in terms of luminescence spectra, which indict that the energy transfer of Gd3+-Eu3+ is efficient. The mechanism of energy transfer from Gd3+ to Eu3+ is a resonant transfer, in which electric dipole-dipole interaction plays a leading role. Furthermore, the doping concentration-dependence of Eu3+ ions on the energy transfer efficiency was also investigated.