Optical properties and applications of rationally designed metal nanostructures: Hollow gold nanospheres


Jin Z Zhang, jzhang@hydrogen.ucsc.edu, Department of Chemistry, U of CA, Santa Cruz, CA 95060, Adam Schwartzberg, amschwartzberg@gmail.com, Department of Chemistry, University of California Berkeley, Berkeley, CA 95072, Tammy Y. Olson, oshiro@chemistry.ucsc.edu, Department of Chemistry, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, and Chun Li, Department of Experimental Diagnostic Imaging, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030.
We have studied the optical and structural properties of different metal nanostructures including aggregates, nanorods, and hollow nanospheres with the goal to optimize their SERS (surface-enhanced Raman scattering) activities. Specifically, we have synthesized and characterized a new metal nanostructure, namely hollow gold nanpphsere (HGNS), that has a unique combination of small size, spherical shape, and strong, narrow, and tunable plasmon absorption. They show significantly improved performance not only for SERS but also for photothermal cancer therapy. Exceptional structural homogeneity leads to a nearly tenfold increase in signal consistency over standard silver substrates for SERS. They are 50 times more effective than solid gold nanoparticle for photothermal cancer therapy. We have also found that it is possible to make long gold nanotubes using magnetic nanoparticles as templates. In addition, unique hollow Au-Ag double nanoshell structures have been designed and successfully synthesized that show enhanced SERS activities over hollow gold nanoshells.