A Novel Method for the Preparation of Silver Halide Nanoparticles from Their Bulk Solid Using Microemulsions

Nanoparticles of silver halides are widely used to study the quantum confinement effects in indirect band gap semiconductors [1]. These particles are typically prepared by carrying out a precipitation reaction in the water pools of w/o microemulsions, or reverse micelles, by mixing two identical microemulsions containing aqueous solutions of AgNO3 and KBr, or other halides [2]. The mixing of two microemulsions technique is the most common technique used to prepare precipitates of nanoparticles employing microemulsions. Precipitation reactions are known to have rapid kinetics and are limited by the opening of the surfactant layer upon collision of the reverse micelles carrying the reactants [3]. Slow opening of the surfactant layer results in simultaneous nucleation and aggregation, which in turn, results in the formation of larger particles with wider size distribution. In addition to the above limitation, microemulsion techniques generally suffer from low reactant solubilization capacity [4].