Influence of solvent on the structural and morphological properties of AgI particles prepared using ultrasonic spray pyrolysis

Silver iodide particles were synthesized in the process of ultrasonic spray pyrolysis using aqueous solutions of thermodynamically stable silver iodide clusters as precursor. The AgI particles were collected in solvents of different polarities such as water, 2-propanol and toluene. In order to study influence of solvent and aging time on the morphological and structural properties of the AgI particles ultra-filtration was employed to isolate solid material from solution. The scanning electron microscopy showed that morphology of the AgI particles is different for different solvents. The AgI particles with hexagonal/triangular shape were obtained in water and toluene, while in 2-propanol hollow spheres were formed. The X-ray diffraction analysis, besides wurtzite hexagonal and zinc blende cubic phases, revealed appearance of tetragonal high-pressure AgI modification for sample collected in toluene and for sample aged in 2-propanol. The aging in toluene induced transformation of all three modifications into single phase with one preferred orientation. (c) 2007 Elsevier B.V. All rights reserved.