The growth of AgI nanoparticles by iodization of Ag1-xSbx thin films under ambient conditions has been investigated. Mechanically well ground mixtures of Ag and Sb were thermally evaporated onto microscopic glass slides. They were subsequently iodized at ambient temperature in the dark and characterized by XRD, SEM and optical measurements. Preliminary results infer that the addition of Sb favors the island growth of AgI, but greatly retards the rate of AgI particle growth, resulting in nanometric sized AgI particles. 5% Sb doped Ag films with optimal thickness (~ 200 Å) are found to be ideal for the formation and long term stabilization of γ-AgI thin films. Sb also plays a crucial role in controlling the exciton formation process.