Kalwarczyk, Ewelina;
Kabaciński, Piotr;
Kardaś, Tomasz M.;
Górecka, Ewa;
Bilski, Henryk;
Fiałkowski, Marcin
A Seedless Method for Gold Nanoparticle Growth inside a Silica Matrix: Fabrication of Materials Capable of Third‐Harmonic Generation in the Near‐Infrared
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Medientyp:
E-Artikel
Titel:
A Seedless Method for Gold Nanoparticle Growth inside a Silica Matrix: Fabrication of Materials Capable of Third‐Harmonic Generation in the Near‐Infrared
Beteiligte:
Kalwarczyk, Ewelina;
Kabaciński, Piotr;
Kardaś, Tomasz M.;
Górecka, Ewa;
Bilski, Henryk;
Fiałkowski, Marcin
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>A composite in which gold nanoparticles (AuNPs) approximately 10 nm in size are embedded in amorphous transparent silica matrix has been produced. The synthetic protocol uses HAuCl<jats:sub>4</jats:sub> as the Au ion source, tetraethoxysilane (TEOS) as the SiO<jats:sub>2</jats:sub> precursor, and <jats:sc>l</jats:sc>‐ascorbic acid (AA) as the reducing agent. AA is employed before the sol‐gel process in an amount sufficient only for reduction of Au<jats:sup>3+</jats:sup> ions to Au<jats:sup>+</jats:sup>. By using a cationic surfactant, benzylcetyldimethylammonium chloride hydrate (BDAC) and/or cetyltrimethylammonium bromide (CTAB), the Au<jats:sup>+</jats:sup> ions are encapsulated within metalomicelles, which prevents them from being reduced to Au<jats:sup>0</jats:sup> and enables their homogeneous distribution in the gel. Reduction of Au<jats:sup>+</jats:sup> to Au<jats:sup>0</jats:sup> and the growth of the AuNPs occurs at room temperature during the gelation, and arises from the release of EtOH during the hydrolysis of TEOS. The composites contain 0.027 wt % of Au. They exhibit nonlinear optical behavior characterized by the third‐order nonlinear refraction index, n<jats:sub>2</jats:sub>, in the range 3.6–5.7×10<jats:sup>−16</jats:sup> cm<jats:sup>2</jats:sup> W<jats:sup>−1</jats:sup> at λ=1.030 μm. The composites are capable of effective third‐harmonic generation of ultrashort near‐IR (210 fs, 1.030 μm) laser pulse through a direct third‐order mechanism.</jats:p>