Characterization of SERS-fluorescence bimodal nanocomposites from Au-decorated CaTiO3:Eu3+

Surface-enhanced Raman scattering (SERS)-fluorescence bimodal composites have attracted great interest for biomedical applications. Herein, we report the characterization of Au-decorated CaTiO3:Eu3+ nanocomposites (CaTiO3:Eu3+@Au NCs) using SERS and fluorescence properties. X-ray diffraction (XRD) of the CaTiO3:Eu3+@Au NCs shows orthorhombic phases, which are in good agreement with the standard CaTiO3 XRD peaks. The photoluminescence (PL) spectra show a strong visible red emission at 614 nm (D-5(0) -> F-7(2)) with an excitation wavelength of 380 nm. The PL-emission intensity of the CaTiO3:Eu3+@Au NCs increased more than that of the CaTiO3:Eu3+ powder. The maximum PL-emission intensity of the CaTiO3:Eu3+@Au NCs was obtained at an Au doping concentration of 0.8 mol/L; however, the intensity at higher Au doping concentrations (> 0.8 mol/L) was lower. This behavior is consistent with the SERS results. These results suggest that varying the Au nanoparticle concentration can control the PL-emission intensity and SERS of the CaTiO3:Eu3+@Au NCs. Therefore, CaTiO3:Eu3+@Au NCs may be useful for multiplex detection and bioimaging.