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⁺, ⁸S_7/2, was selectively excited to a ⁶I_J 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. - Highlights: • Uniform silica nanorods co-doped with Gd³⁺ and Eu³⁺ have been prepared using cetyltrimethylammonium bromide (CTAB) as surfactant template by the sol–gel method. • Rare earths doping enhanced the luminescence activity under UV excitation. • Energy transfer from Gd³⁺ to Eu³⁺ is a resonant transfer, in which electric dipole–dipole interaction plays a leading role. • The effect of doping concentrations of Eu³⁺ ions on the energy transfer efficiency was investigated