Large-scale growth and end-to-end assembly of silver nanorods by PVP-directed polyol process

Silver nanorods with uniform diameters and large aspect ratios have been synthesized in large scale by reducing silver nitrate in ethylene glycol solution in the presence of poly(vinyl pyrrolidone) K-30 (PVP, M(w)similar to44,000-54,000) and nanoscale gold seeds. The phenomenon of the end-to-end assembly of the as-grown silver nanorods has been found for the first time. The techniques of powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy and selected area electron diffraction were used to characterize the obtained samples. The results indicate that the selective adsorption of PVP on the side surfaces of {100} and the end surfaces of {111} plays a crucial role for the growth of the anisotropic silver nanostructures. The end-to-end assembly of the silver nanorods is resulted from the approaching, attracting and welding the pre-grown silver nanorods. The connection of silver nanorods through end-to-end assembly without any exotic connectors will have potential applications in the future nanoscale electronic circuits. (C) 2003 Elsevier B.V. All rights reserved.