Investigation of photolysis and photochemical transformations in metal layer halides with optical methods

Abstract

In the present work processes of photolysis and photochemical transformations in crystals, thin films, and heterogeneous environments of layer cadmium, lead, and zinc halides have been investigated. It has been found that photolysis takes place in these materials at excitation of electron-hole couples. Excessive metal atoms serve as photodecay centers. Photolysis kinetics are determined by halogen diffusion. Products of photolysis are metallic and partly oxide phases. The maximal photolysis degree is determined by the critical size of metallic inclusions. It has been shown that copper impurity leads to photochemical reactions (PCR) in cadmium halides. PCR in CdI 2 - Cu crystals is caused by photothermal decay of copper- intrinsic defect complexes. In CdBr 2 - Cu PCR takes place as a result of copper impurity photoionization, and in CdCl 2 - Cu it is a result of recharging Cu + yields Cu 2+ .