Ag:TiO2 plasmonic nanocomposite films obtained by RF magnetron co-sputtering

Abstract

It is known that TiO2 is a wide-gap semiconductor, which due to its low cost and photocatalytic properties has found great application in purification of water and organic pollution, as well as solar energy [1]. To expand an application area, various methods of functionalization and alloying of TiO2 with various metallic and nonmetallic impurities and particles are used. One of these ways is usage of plasmon nanoparticles, like Au and Ag, to increase the absorption region in the visible range [2]. In this work, plasmon nanocomposite films of Ag:TiO2 were obtained by RF magnetron co-sputtering [3]. It was revealed that the films consist of an amorphous TiO2 matrix and isolated silver nanoparticles with 3-5 nm diameter. The optical absorption spectra of Ag:TiO2 nanocomposite films are characterized by local maxima at 465-480 nm corresponding to light scattering plasmon resonance (LSPR). Photoelectrochemical studies of Ag:TiO2 nanocomposite films in 0.1 M Na2SO4 under illumination with 465 nm light showed that silver nanoparticles presence in the matrix increases the photoconductivity. The quantum yield for Ag:TiO2 composite films increases significantly, while for a pure TiO2 film this value does not exceed 0.5%. In addition, work was carried out related to the degradation of the methylene blue dye (MB dye) under the direct action of solar radiation, from which it follows that the presence of silver nanoparticles in the TiO2 matrix increases the rate of decoloration of the aqueous solution with MB dye. Thus, the obtained TiO2:Ag nanocomposite films are a promising material for use in nonlinear optics, electronics, electrooptics, photocatalytic and antireflection coatings and photoconverters, as well as in biomedicine as antibacterial coatings.