Strain-Induced Confinement of Excitons in Quasi-free AgI Nanoparticles

The optical spectra of vapor quenched metastable Ag−Cu thin films progressively iodized under ambient conditions have been measured. Delayed evolution and inhomogeneous broadening of the exciton absorption at 420 nm of the spatially confined γ-AgI nanoparticles were clearly seen by the development of Z1,2 exciton peak − iodization being controlled by the as-quenched Ag−Cu clusters. Cu addition not only restricts the particle size, but also favors the island type growth mode.