title: Real-time visualization of diffusion-controlled nanowire growth in solution.
abstract: This Letter shows that copper nanowires grow through the diffusion-controlled reduction of dihydroxycopper(I), Cu(OH)2(-). A combination of potentiostatic coulometry, UV-visible spectroscopy, and thermodynamic calculations was used to determine the species adding to growing Cu nanowires is Cu(OH)2(-). Cyclic voltammetry was then used to measure the diffusion coefficient of Cu(OH)2(-) in the reaction solution. Given the diameter of a Cu nanowire and the diffusion coefficient of Cu(OH)2(-), we calculated the dependence of the diffusion-limited growth rate on the concentration of copper ions to be 26 nm s(-1) mM(-1). Independent measurements of the nanowire growth rate with dark-field optical microscopy yielded 24 nm s(-1) mM(-1) for the growth rate dependence on the concentration of copper. Dependence of the nanowire growth rate on temperature yielded a low activation energy of 11.5 kJ mol(-1), consistent with diffusion-limited growth.
authors: Department of Chemistry, Duke University , Durham, North Carolina 27708, United States.
authors: Shengrong
authors: S
authors: Ye
authors: Zuofeng
authors: Z
authors: Chen
authors: Yoon-Cheol
authors: YC
authors: Ha
authors: Benjamin J
authors: BJ
authors: Wiley
mesh_terms: D003300:Copper / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D053770:Nanowires / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006878:Hydroxides; C508959:copper hydroxide; D003300:Copper