Magnetron Sputtering Deposition of Ag/TiO₂ Nanocomposite Thin Films for Repeatable and Multicolor Photochromic Applications on Flexible Substrates

Abstract

It is reported on a reactive magnetron sputtering‐based deposition method to synthesize, at room temperature, photochromic nanocomposite thin films consisting of Ag nanoparticles sandwiched between nanoporous TiO2 layers. The fabrication process is compatible with large‐scale production and functional flexible substrates. It is shown that when TiO2 is deposited in the metallic mode, the formation of Ag metal nanoparticles induces localized surface plasmon resonances in the visible range and therefore the as‐deposited samples are colored. In contrast, when TiO2 is deposited in the compound mode, the trilayer samples are colorless because silver oxidizes during TiO2 deposition. It is demonstrated that the colorless samples can be colored under ultraviolet (UV) laser exposure at 244 nm due to the reduction of oxidized silver and the formation of metallic Ag nanoparticles. Moreover, irradiation at 647 nm wavelength of colored samples (as‐prepared or after UV exposure) gives rise to changes in the particle morphology that strongly modifies the film absorbance and results in a color transition from blue to orange. The choice of the irradiation wavelength allows controlling the color saturation of the sample up to the complete discoloration by using a visible laser at 488 nm. All these photochromic mechanisms are repeatable during cyclic processes.

Optical Properties of Hybrid Organic‐Inorganic Materials and their Applications

“…is still a subject of extensive investigation. Numerous papers reporting smart photochromic properties of Ag [211][212][213][214][215] species deposited onto TiO 2 substrates have appeared in the last years. Interesting properties are developed in titanate nanotubes loaded with AgCl or Ag NPs.…”

Mussel‐Inspired Flexible, Durable, and Conductive Fibers Manufacturing for Finger‐Monitoring Sensors

“…Thus, the desired coating materials should penetrate into the fibrous structures . Several attempts have been made to metalize fibers such as thermal evaporation, atomic layer deposition, magnetron sputtering, and galvanic deposition . But the fabrication via above‐listed methods does not have chemical bonds or other tethering force between the metallic layers and the surface of fibers.…”

Thin films of Ag–Au nanoparticles dispersed in TiO2: influence of composition and microstructure on the LSPR and SERS responses

“…Beyond the work developed by F. Vaz et al [4,35,36], few studies addressed the synthesis of Ag/TiO2 [37,38] and Au/TiO2 [39,40] thin films by magnetron sputtering followed by a heat treatment, as an efficient and versatile way to control the morphology, particle growth and optical properties of these nanocomposites. Therefore, the application of this method to prepare bimetallic Ag-Au nanoparticles on a TiO2 matrix, seems to be a very promising way to achieve different Ag/Au atomic ratios in a dielectric matrix such as TiO2, which, in principle, will allow to tune the LSPR peak position between those of the corresponding monometallic counterparts.…”