Polyethylenimine-interlayered core–shell–satellite 3D magnetic microspheres as versatile SERS substrates

摘要: Precise fabrication of subtle nanogaps amid individual nanoparticles or between adjacent ones to obtain the highest SERS enhancement is still a challenge. Here, we reported a novel approach for fabricating core–shell–satellite 3D magnetic microspheres (CSSM), that easily form a porous 1.5 nm PEI interlayer to accommodate molecules and create sufficient hotspots between the inner Fe3O4@ Ag core and outer assembled Au@ Ag satellites. Experiments and finite-difference time-domain (FDTD) simulation demonstrated that the …