This article provides a brief account of solution-phase methods that generate silver and gold nanostructures with well-controlled shapes. It is organized into five sections: The first section discusses the nucleation and formation of seeds from which nanostructures grow. The next two sections explain how seeds with fairly isotropic shapes can grow anisotropically into distinct morphologies. Polyol synthesis is selected as an example to illustrate this concept. Specifically, we discuss the growth of silver nanocubes (with and without truncated corners), nanowires, and triangular nanoplates. In the fourth section, we show that silver nanostructures can be transformed into hollow gold nanostructures through a galvanic replacement reaction. Examples include nanoboxes, nanocages, nanotubes (both single- and multi-walled), and nanorattles. The fifth section briefly outlines a potential medical application for gold nanocages.We conclude with some perspectives on areas for future work.
Benjamin Wiley is a graduate student in the chemical engineering program at the University of Washington. He received a BS degree in chemical engineering from the University of Minnesota in 2003. As a member of Younan Xia's group at the University of Washington, his work focuses on the synthesis of metallic nanostructures with controllable shapes and understanding their nucleation/growth mechanisms. He is a recipient of the IGERT Fellowship Award (supported by the National Science Foundation) from the Center of Nanotechnology at the University of Washington, and a Graduate Student Gold Award from MRS (2005).
Wiley can be reached by e-mail at email@example.com.
Yugang Sun is a research associate at the University of Illinois at Urbana-Champaign working with John Rogers. He received his BS and PhD degrees in chemistry from the University of Science and Technology of China (USTC) in 1996 and 2001, respectively. After graduating from USTC, he worked as a postdoctoral research associate with Younan Xia at the University of Washington until the end of 2003. His research interests include the synthesis and characterization of nanostructures, micro- and nanofabrication, bioanalysis, and devices for photonics and electronics.
Sun can be reached by e-mail at firstname.lastname@example.org
Jingyi Chen is a graduate student in the Department of Chemistry at the University of Washington, where she works on the synthesis of nanostructured materials and functionalization of their surfaces. She received her BS degree in chemistry in 1997 from Zhong-Shan University in Guangzhou, China; her MS degree in chemistry in 2000 from the Guangzhou Institute of Chemistry, Academia Sinica; and her MS degree in biochemistry in 2002 from Buffalo State College. She is a recipient of the Nanotechnology Fellowship Student Award (2003–2005) from the Center for Nanotechnology at the University of Washington and an MRS poster award (2005).
Chen can be reached by e-mail at email@example.com
Hu Cang is a postdoctoral researcher working with Younan Xia and Xingde Li at the University of Washington. He received his BS degree in chemical physics from the University of Science and Technology of China (USTC) in 1998, his MS degree in electrical engineering from Stanford University in 2003, and his PhD degree in chemistry from Stanford (with Michael D. Fayer) in 2004. His research interests include nonlinear optical spectroscopy, dynamics of complex liquids, glass transitions, and optical coherence tomography.
Cang can be reached by e-mail at firstname.lastname@example.org
Zhi-Yuan Li is a professor of physics in the Institute of Physics at the Chinese Academy of Sciences in Beijing. He received his BS degree in optoelectronics from the University of Science and Technology of China (USTC) in 1994 and then worked as a graduate student on photonic crystals and near-field optics at the Institute of Physics, Chinese Academy of Sciences. After obtaining his PhD degree in 1999, he worked as a postdoctoral fellow at the Hong Kong University of Science and Technology, the University of Washington, and Ames National Laboratory. His research interests include photonic crystals, nanophotonics, near-field optics, and integrated optics.
Li is the co-author of more than 60 peerreviewed publications. He currently serves as a regular referee for several prominent physics and optics journals, including Physical Review Letters, Applied Physics Letters, Physical Review B and E, and Optics Letters.
Li can be reached by e-mail at email@example.com
Xingde Li is an assistant professor of bioengineering at the University of Washington. He received his BS degree in applied nuclear physics from the University of Science and Technology of China (USTC) in 1990. He then earned his PhD degree in condensed-matter physics and biomedical optics from the University of Pennsylvania in 1998 (with Arjun G. Yodh and Britton Chance), at which point he joined the Research Laboratory of Electronics at MIT for postdoctoral training (with James G. Fujimoto).
Li's research centers on low-coherence interferometry, high-resolution optical coherence tomography, light scattering, photon diffusion, light–tissue interactions, biological tissue absorption and scattering spectroscopy, optical molecular contrast agents, and optically based novel miniature biomedical devices. He has received a National Science Foundation CAREER Award and has authored or co-authored more than 30 peer-reviewed publications.
Li can be reached by e-mail at firstname.lastname@example.org
Younan Xia, Guest Editor for this issue of MRS Bulletin, is a professor of chemistry at the University of Washington. He received his BS degree in chemical physics from the University of Science and Technology of China (USTC) in 1987 and then worked as a graduate student on inorganic nonlinear optical crystals at the Fujian Institute of Research on the Structure of Matter, Academia Sinica. He earned his MS degree in inorganic chemistry from the University of Pennsylvania (with Alan G. MacDiarmid) in 1993 and his PhD degree in physical chemistry from Harvard University (with George M. Whitesides) in 1996. He then stayed at Harvard and worked as a postdoctoral fellow with both Whitesides and Mara Prentiss. He began as an assistant professor of chemistry at the University of Washington in 1997.
Xia's research interests include nanostructured materials, self-assembly, photonic crystals, colloidal chemistry, microfabrication, surface modification, electrospinning, conducting polymers, microfluidics, and novel devices for photonics, optoelectronics, and displays.
He has received many awards, including a National Science Foundation CAREER Award, the Camille Dreyfus Teacher–Scholar Award, and the Victor K. LaMer Award from the American Chemical Society. He has been an Alfred P. Sloan Research Fellow and a David and Lucile Packard Fellow. Xia is the co-author of more than 200 peer-reviewed publications and has edited a number of special issues and books on nanostructured materials. He currently serves as an associate editor for Nano Letters.
Xia can be reached by e-mail at email@example.com