Seed-mediated growth method to prepare cubic copper nanoparticles

A new and simple method has been reported here which can be applied to cont rol simultaneously the shape and size of the copper nanoparticles, without using any capping agent or template. By this method, cube-shaped copper nan oparticles in the size range similar to 75-250 nm were formed from smaller spherical copper particles. At the first stage, 5-6 nm spherical copper par ticles were prepared from aqueous copper sulphate solution by borohydride r eduction. In the second stage, these small particles were mixed with approp riate amount of copper sulphate and sodium ascorbate, which resulted in the production of larger size cubic copper particles. In the latter step, the new grown larger particles acted as seed and grew larger due to the reducti on of copper ions by ascorbate ion on their surfaces, Thus cubic copper nan oparticles of varied size regime were produced by ascorbate ion by varying the ratio of copper seed particles to copper ion concentrations in solution .