Semiconductor overlayers for protecting silver nanoparticles of dye sensitized solar cells based on atomic layer deposition

Silver nanoparticles have been found many interesting applications, such as absorption amplifiers in dye-sensitized solar cells. However, silver nanoparticles are easily oxidized. In order to protect silver nanoparticles, atomic layers of TiO₂ were deposited onto silver nanoparticles coated to a glass slide. Then the glass slide was exposed to corrosive I^-/I₃^- solutions, and the degree of silver etching was measured via scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy (UVS). It was found that 3 nm (30 cycles) of Al₂O₃ with 9 nm of (90 cycles) TiO₂ could completely protect silver nanoparticles from oxidization.