Electrochemical growth of copper nanoparticles: Structural and optical properties

Abstract

In the present study, spherical copper nanoparticles are grown by an inexpensive and template free electrochemical technique on fluorine doped tin oxide (FTO) substrate through an aqueous solution of copper sulfate (CuSO4·5H2O) with citric acid as a complexing agent. The deposition time and electrode potential were found to play an important role in controlling the growth of nanocrystal during electrodeposition. In this method, by selecting precisely the electrolyte concentration, the spherical copper nanoparticles of different size and number density were synthesised by varying the deposition time and electrode potential. The morphological and structural evolution of as prepared copper nanoparticles were characterized by scanning electron microscopy and X- ray diffraction techniques. The regular, uniform and highly dense spherical copper nanoparticles with an approximate size of 512nm were grown directly on FTO substrate. The time as well as voltage dependent growth evolution of copper nanoparticles is explained with the help of diffusion controlled progressive growth mechanism. The contact angle measurement showed the hydrophobic nature of copper nanoparticles with water contact angle about 112°. The optical properties were studied by using UV–visible absorption spectroscopy. The optical properties showed the strong absorption peaks at 334 and 400nm with broad absorption around 545nm in the visible region of electromagnetic waves. These copper nanoparticles can be used effectively in variety of applications such as catalysis, biosensors, plasmon enhancement of light harvesting in photovoltaic cells, electronic nanodevices, fuel cells etc.