Ionic conductivity of small-grain polycrystals of silver iodide

Small particles of AgI with various average size (140-680 nm) have been prepared by a gas-evaporation method. The powder X-ray diffraction patterns show that they are mixture of gamma- and beta-phases, and the mass fraction of the latter is roughly estimated at 20-25%. The room temperature conductivity of a polycrystalline pellet of small AgI particles shows enhancement by decreasing particle size, and the conductivity of 1.4 x 10(-4) Omega(-1) cm(-1) has been observed in 140 nm-grain AgI polycrystal. The overall activation energy for conduction varies from 0.38 to 0.28 eV, depending on the average size of the particles. (C) 1998 Elsevier Science B.V. All rights reserved.