Growth of Ag3Sn and Sn Nanoparticles Based on the Variation of Reaction Conditions

Abstract

Tin and tin-based nanoalloys especially Sn-3.5Ag (wt.%) eutectic alloys have been prepared by numerous methods as the promising alternative solder in electronic packaging application. However, issues of agglomeration and oxidation emerged owing to shrinking size of nanoparticles. In this study, the Sn/Ag3Sn nanoparticles as small as 10[Formula: see text]nm have been synthesized successfully through chemical reduction method. Concentration of precursor and reducing agent have been studied so as to control the reaction rate, thus achieving the optimized conditions avoiding agglomeration. A centralized size distribution has been achieved by separating nucleation and growth periods. It has been revealed that the obtained nanoparticles are composed of [Formula: see text]-Sn and Ag3Sn which represent a successful co-reduction. [Formula: see text]-Sn and Ag3Sn NPs have various average size for their distinct critical nucleation radius and disparate mole ratio of Sn and Ag. The [Formula: see text]-Sn surface has almost 4-nm thick amorphous tin oxide layer but Ag3Sn surface has not, because the lattice distortion caused by the replacement of silver by tin hinders the diffusion of oxygen, improving oxidation resistance and dispersing performance.