B. Babukutty, F. Parakkal, G.M. Bhalero, S.S. Nair
Central University of kerala, India
pp. 215 - 218
Keywords: copper, metal nanoparticles, nanofluids, optical properties
Abstract: Copper oxide shelled copper nanofluids are synthesized with surfactant trioctylphosphine oxide (TOPO) using sulphates precursors. The fluids were structurally characterised by X-ray Diffraction (XRD). Surface and morphological characterization are carried out by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) respectively. The TEM images show that the average grain size ranges from 10 to 15nm. Quantum confinement effects in these nanofluids are analyzed by spectrophtometry. Optical absorption characteristics are studied by UV Visible spectrophotometer (PG-T80+UV VIS spectrophotometer). Absorption spectra while plotted as Tauc curves shows different band edges, keeping the band edge of the bulk metallic nanoparticles along with other edges corresponding to higher energies. Bigger particles above 10 nm show bulk like behavior contributing to the band gap of 0.8 eV while confined particles contribute to the second and most dominant band edge corresponding to a band gap of 3 eV. The particles, because of their smaller size, have much higher band gap than that of bulk material. Presence of both copper and copper oxide is confirmed by both XRD and Energy Dispersive X-ray Spectroscopy ( EDX).