Boat-like Au nanoparticles embedded mesoporous γ-AlO films: an efficient SERS substrate.

Dandapat, Anirban; Pramanik, Sourav; Bysakh, Sandip; De, Goutam

Boat-like Au nanoparticles (NPs) have been synthesized within the mesoporous γ-AlO films. First, mesoporous γ-AlO film was prepared using aluminum alkoxide derived boehmite sol in the presence of CTAB as structure directing agent. The film was heat-treated at 500 °C to obtain γ-AlO film with an average pore diameter of 4.3 nm. HAuCl solution was then soaked into the porous film followed by heat-treatment at 500 °C to generate Au NPs. The blue-colored films so obtained were characterized by UV-visible spectroscopy, grazing incidence X-ray diffraction, FESEM, and TEM studies. FESEM and TEM studies reveal the formation boat-like Au NPs in γ-AlO film matrix. Cross-sectional FESEM shows the thickness of the films to be ~2.2 μm. These nanocomposite films were used as a unique surface-enhanced Raman scattering (SERS) substrate for easy detection of low concentration (10 M) analyte (methylene blue) molecule. Boat-like shape of Au NPs have several edges and junctions that contain high density of hotspots to exhibit very high SERS signals. Due to such shape of Au NPs, the films also show strong absorption in the visible-NIR region that would extend the use of the films in heat-absorbing and biomedical applications.

GOLD nanoparticles; MESOPOROUS materials; ALUMINUM oxide films; SERS spectroscopy; SUBSTRATES (Materials science); METHYLENE blue; X-ray diffraction

Journal of Nanoparticle Research, 2013, Vol 15, Issue 7, p1

1388-0764

Academic Journal

10.1007/s11051-013-1804-1