The optical properties and chemical decomposition of lead iodide

The optical properties of lead iodide have been measured and the fundamental absorption spectrum is interpreted in terms of ionization and excitation processes. These processes may be regarded as transitions from a split valence band to the conduction band and to exciton levels lying above and below the minimum of the conduction band. This inter­pretation is supported by measurements of photoconductivity and photodecomposition. Two mechanisms are suggested to explain the occurrence of photodecomposition and electron irradiation damage in this substance.