Shape-controlled synthesis of magnetic-optical core-shell hybrid nanoparticles

S. Bhana, X. Huang
The University of Memphis, US

Keywords: nanoparticles, anisotropic, magnetic-optical, core-shell, hybrid, synthesis

Summary:

Hybrid nanomaterials possessing dual magnetic/optical properties are of considerable interests to many areas, ranging from material science to medicine and biology. They are promising for a broad range of applications including catalysis, energy conversion, biological separation, medical diagnosis and treatment. Anisotropic magnetic-optical nanoparticles give better or new properties compared to spherical ones due to their high curvature and polarization-sensitive geometry. However, the preparation of anisotropic magnetic-optical core-shell nanoparticles remains a major challenge. We developed a facile method to make compact magnetic-optical core-shell nanoparticles in different shapes. The method is based on the anisotropic growth of gold shell onto silver-seeded iron oxide nanoparticles in a gold growth solution that containing silver ions, ascorbic acid and cetyltrimethylammonium bromide surfactant. By controlling the concentration of silver ions and cetyltrimethylammonium bromide, iron oxide-gold core-shell nanoparticles in spheres, ovals, pins and stars were prepared. The anisotropic nanoparticles are superparamagnetic and exhibit superior surface enhanced Raman scattering activities and photothermal properties.