Study on Electric Properties and Photosensitivity of Epitaxial AgCl/AgBr(I) cubic Emulsion Grains

Three epitaxial AgCl/AgBr(I) cubic emulsion grains were prepared successfully by cpitaxial deposition of AgCl on （111） surfaces of three tetradecahedra AgBr(I) host grains made at the condition of different pAg values by microcomputer-controlled balance double-jet method. X-ray diffraction patterns of these epitaxial emulsion grains indicated separated two-phase structure corresponding or host AgBr(I) phase and new AgCl one respectively, which implied there is no strong dissolution between AgBr(I) and AgCl. The dielectric loss curves of epitaxial grains showed two separated peaks corresponding to the contributions of AgBr(I) host phase and AgCl epitaxial one to ionic conductivity respectively. The decay process of photoconductivity for both host and epitaxial grains was composed of a slower one and a fast one, each of which obeys first-order kinetic rule. The epitaxial procedure modified effectively the amount and mean lifetime of photoelectrons. The photosensitivities of epitaxial emulsions were much higher than that of host emulsions, which can be attributed to an optimization of electric properties due to epitaxial growth to the advantage of latent image concentration and selective development.