Abstract
After a short time reflux heating, thiol-capped gold nanoparticles became nearly monodisperse from a polydispersed particle system. We investigated the reflux-heated temperature how to affect size evolution of gold nanoparticles. With the same amount of dodecanethiol, the gold colloid was reflux heated at different temperatures. We found that reflux-heated temperature decreased, the time that gold nanoparticles achieved monodisperse increased and size of stable gold nanoparticles increased. In addition, after prolonged heating, they have the tendency to aggregate and coalescence. Then, we changed the amounts of dodecanethiol to observe whether the known effects of temperature may be affected. The results showed that the effect of reflux-heated temperature changed while amounts of dodecanethiol were not enough in the gold colloid. In the other hand, the effect of dodecanethiol was changed by reflux heating. Through reflux heating, more amounts of dodecanethiol cause the stable particle size of gold nanoparticle increase, opposite to the results before reflux heated. Besides, we applied electric field through gold colloid during reflux heating. The results was the effect which the reflux heated temperature under applied electric field have on that gold nanoparticles approached nearly monodisperse system was consistent with that without electric field.