Morphology tuning of mono-disperse silver nanoparticles by reaction temperature adjustment

Mono-disperse silver nanoparticles with tunable morphologies have been fabricated by reducing AgNO₃ in the presence of N-dimethylformamide (DMF) and larger molecular weight poly (vinylpyrrolidone) (PVP). By adjusting the reaction temperature, the conversion of the morphology can be easily and effectively controlled. The crystal structures and growth mechanism of mono-disperse silver nanoparticles were studied by using TEM, HR-TEM, FFT, XRD and UV-Vis spectra data. The results show that the morphologies of nanoparticles with spherical shape can be adjusted to a truncated triangle/hexagon along with the change of reaction temperature from 80 to 120 °C. It is found that the shape transformation from sphere to truncated triangle is caused by the difference in surface energy and the selective adsorption of PVP on silver atom.