Assembly of gold composite thin films by spontaneous reduction of subphase chloroaurate anions beneath vitamin E Langmuir monolayers

Gold composite thin films were generated by the spontaneous reduction of chloroaurate (AuCl4−) ions beneath vitamin E (VE) Langmuir monolayer. The monolayer and gold nanocomposite LB films were then characterized by surface pressure–area (π–A) isotherms, ultraviolet–visible spectroscopy (UV–vis), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction analysis (XRD), respectively. The results showed that the limiting area/VE molecule on the HAuCl4 solution subphase was larger than that on the pure water subphase, and it increased with reaction time. The morphologies of Au particles such as spherical-like, triangular and multiply-twinned particles (MTPs) could be observed. The XRD pattern indicated that the gold particles in LB films were face-centered cubic (fcc) polycrystalline. The plasmon absorption intensities of gold composite LB films increased with the film thickness, which suggested that the monolayer containing gold particles could be transferred successfully onto the substrates.