Sol–Gel Synthesis and Characterization of Ag and Au Nanoparticles in SiO2, TiO2, and ZrO2 Thin Films

Silver and gold nanoparticles were synthesized by the sol-gel process in SiO 2 , TiO 2 , and ZrO 2 thin films. A versatile method, based on the use of coordination chemistry, is presented for stabilizing Ag + and Au 3+ ions in sol-gel systems. Various ligands of the metal ions were tested, and for each system it was possible to find a suitable ligand capable of stabilizing the metal ions and preventing gold precipitation onto the film surface. Thin films were prepared by spin-coating onto glass or fused silica substrates and then heat-treated at various temperatures in air or H 2 . atmosphere for nucleating the metal nanoparticles. The Ag particle size was about 10 nm after heating the SiO 2 film at 600°C and the TiO 2 and ZrO 2 films at 500°C. After heat treatment at 500°C, the Au particle size was 13 and 17 nm in the TiO 2 and ZrO 2 films, respectively. The films were characterized by UV-vis optical absorption spectroscopy and X-ray diffraction, for studying the nucleation and the growth of the metal nanoparticles. The results are discussed with regard to the embedding matrix, the temperature, and the atmosphere of the heat treatment, and it is concluded that crystallization of TiO 2 and ZrO 2 films may hinder the growth of Ag and Au particles.

[1]  G. Battaglin,et al.  Structural and optical properties of silver-doped zirconia and mixed zirconia-silica matrices obtained by sol-gel processing , 1999 .

[2]  H. Kozuka,et al.  Preparation of coating films doped with gold metal particles from methyltriethoxysilane-tetraethoxysilane solutions , 1994 .

[3]  U. Schubert,et al.  Metal complexes in inorganic matrixes. 7. Nanometer-sized, uniform metal particles in a silica matrix by sol-gel processing of metal complexes , 1991 .

[4]  Paolo Mazzoldi,et al.  Silver nanocrystals in silica by sol-gel processing , 1996 .

[5]  Kohei Kadono,et al.  Sol-Gel Processing and Optical Nonlinearity of Gold Colloid-Doped Silica Glass , 1993 .

[6]  Plinio Innocenzi.  Methyltriethoxysilane-derived coatings for optical applications , 1994, Optics & Photonics.

[7]  François Hache,et al.  Optical nonlinearities of small metal particles: surface-mediated resonance and quantum size effects , 1986 .

[8]  R. Reisfeld,et al.  Absorption spectra, energy dispersive analysis of X-rays and transmission electron microscopy of silver particles in sol-gel glass films , 1988 .

[9]  Vollmer,et al.  Width of cluster plasmon resonances: Bulk dielectric functions and chemical interface damping. , 1993, Physical review. B, Condensed matter.

[10]  H. Nasu,et al.  Preparation of Au-Doped Silica Glass by Sol-Gel Method , 1992 .

[11]  Sumio Sakka,et al.  Sol-gel preparation of metal particle/oxide nanocomposites , 1994, Optics & Photonics.

[12]  A. Hinsch,et al.  The production of small colloidal silver particles in thin SiO2 sol-gel glass layers , 1992 .

[13]  O. Lev,et al.  Direct Synthesis and Characterization of Gold and Other Noble Metal Nanodispersions in Sol−Gel-Derived Organically Modified Silicates , 1999 .

[14]  P. Roussignol,et al.  Surface-mediated enhancement of optical phase conjugation in metal colloids. , 1985, Optics letters.

[15]  H. Nasu,et al.  Preparation of gold microcrystal-doped oxide optical coatings through adsorption of tetrachloroaurate ions on gel films , 1997 .

[16]  H. Schmidt,et al.  Synthesis of Ag-colloids in sol-gel derived SiO2-coatings on glass , 1997 .

[17]  S. Martelli,et al.  A Monte Carlo Estimate of Crystallite-Size and Microstrain Distribution Functions from X-ray Line Broadening , 1995 .

[18]  T. Yazawa,et al.  Preparation and optical property of monolithic silica gel uniformaly dispersed with gold colloid from aqueous solution , 1994 .

[19]  Martin Mennig,et al.  Gold colloids in sol-gel-derived SiO2 coatings on glass and their linear and nonlinear optical properties , 1994, Optics & Photonics.

[20]  Sumio Sakka,et al.  Preparation of gold colloid-dispersed silica coating films by the Sol-Gel method , 1993 .