Modification of Bi6Fe1.9Co0.1Ti3O18/SiO2/NaGdF4:Yb3+,Er3+ nanocomposites with different SiO2 thicknesses for tunable upconversion luminescent and ferromagnetic properties

摘要

The coexistence of luminescent and magnetic properties in nanocomposites has attracted the interest of many researchers to study nanocomposites due to their unique properties. In this study, we present a convenient synthesis of Bi6Fe1.9Co0.1Ti3O18/SiO2/NaGdF4:Yb3+,Er3+ (BFCTO/SiO2/NGF) core/shell/satellite nanocomposites with precise control over the thickness of the SiO2 shell. By adjusting the amount of tetraethyl orthosilicate (TEOS), we obtained BFCTO/SiO2/NGF samples with different SiO2 thicknesses (0 nm, 8 nm, 13 nm, 18 nm, 25 nm and 36 nm). On account of the SiO2 spacer effectively reducing the absorption intensity around the green and red regions, the optimal upconversion luminescence intensity of BFCTO/SiO2/NGF was observed at a separation distance of 36 nm. Moreover, at room temperature, the hysteresis loop of BFCTO/similar to 13 nm SiO2/NGF obtained the maximum remnant magnetization (2Mr) of 0.13 emu g(-1). Also, the BFCTO/similar to 36 nm SiO2/NGF sample reached the maximum coercive field (2Hc) of 1200 Oe. Besides, the BFCTO/similar to 8 nm SiO2/NGF sample had the best ferromagnetism with a saturated magnetization Ms of 0.63 emu g(-1).