VOLUME 16, NUMBER 13
JUNE 29, 2004
© Copyright 2004 by the American Chemical Society
Communications A Simple Large-Scale Synthesis of Nearly Monodisperse Gold and Silver Nanoparticles with Adjustable Sizes and with Exchangeable Surfactants Hiroki Hiramatsu and Frank E. Osterloh* Department of Chemistry, University of California at Davis, Davis, California 95616 Received March 18, 2004 Revised Manuscript Received April 26, 2004 The importance of gold and silver nanoparticles for areas ranging from electron microscopy (contrast agents),1 analysis (chemical and biological sensors),2-5 electronics (single-electron transistors, electrical connects),6,7 materials (dyes, conductive coatings),8,9 fundamental research, and even catalysis (CO oxidation on Au/TiO2 composites)10,11 is significant. These applications require nanoparticles in the 2-100-nm size range that need to * To whom correspondence should be addressed. E-mail: fosterloh@ ucdavis.edu. (1) Hayat, M. A. Colloidal gold: principles, methods, and applications; Academic Press: San Diego, 1989; 3 vol. (2) Wuelfing, W. P.; Murray, R. W. J. Phys. Chem. B 2002, 106, 3139-3145. (3) Krasteva, N.; Besnard, I.; Guse, B.; Bauer, R. E.; Mullen, K.; Yasuda, A.; Vossmeyer, T. Nano Lett. 2002, 2, 551-555. (4) Kim, Y. J.; Johnson, R. C.; Hupp, J. T. Nano Lett. 2001, 1, 165167. (5) Mirkin, C. A. Inorg. Chem. 2000, 39, 2258-2272. (6) Klein, D. L.; McEuen, P. L.; Katari, J. E. B.; Roth, R.; Alivisatos, A. P. Appl. Phys. Lett. 1996, 68, 2574-2576. (7) Sato, T.; Ahmed, H.; Brown, D.; Johnson, B. F. G. J. Appl. Phys. 1997, 82, 696-701. (8) Musick, M. D.; Keating, C. D.; Lyon, L. A.; Botsko, S. L.; Pena, D. J.; Holliway, W. D.; McEvoy, T. M.; Richardson, J. N.; Natan, M. J. Chem. Mater. 2000, 12, 2869-2881. (9) Wuelfing, W. P.; Zamborini, F. P.; Templeton, A. C.; Wen, X. G.; Yoon, H.; Murray, R. W. Chem. Mater. 2001, 13, 87-95.
be surface derivatizable with hydrophobic and hydrophilic surfactants. In the past, such nanoparticles were synthesized by either one of two methods, the citrate method introduced in 1857 by Faraday,12 and later refined by Frens,13 and the two-phase method originally described by Wilcoxon et al.14 and later modified by Brust et al.15 The citrate method produces nearly monodisperse gold nanoparticles in the size range from 2 to 100 nm.1 Problems of the citrate method are a low gold nanoparticle content of the resulting solutions (
