Optical studies of structurally disordered Ag(Sn)I thin films

• Sn induces disorder in Ag nanostructure by thermal evaporation.
• Growth kinetics of silver iodide upon iodination process
• Exciton transition at room temperature due to quantum confinement effect
• Sn doping increases fluorescence quantum efficiency in AgI films.

Thin films of Ag1 − xSnx (x = 5, 10, 15 and 25 in %) compositions of thicknesses 10, 20 and 30 nm were prepared by using thermal evaporation and then subsequently iodinated in an in-house figure-of-eight iodinator between 3 and 30 h. X-ray diffraction confirms structural disorder in as prepared Ag–Sn films which controlled the iodination process for the formation of silver iodide (AgI) nanostructure. Optical absorption and photoluminescence are employed to monitor the evolution of γ- and β-AgI nanoparticles whose kinetics is effectively controlled by tin (Sn) by way of an expanded timeframe for iodination. This work also includes the formation of AgI nanodiscs and the fourfold enhancement of photoluminescence relative to undoped AgI clearly and unequivocally delineating the role of Sn.