Preparation and characterization of polymeric thin films containing gold nanoshells via electrostatic layer-by-layer self-assembly

• Prepared gold nanoshells with broad light absorption from visible to near IR.
• Added the gold nanoshells to polyethyleneimine films via layer-by-layer assembly.
• The resulting layered thin films exhibited minimal gold nanoshell aggregation.

As an initial step in the development of surfaces for collecting thermal energy, gold shell/silica core particles (~ 200 nm in diameter with shells ~ 25 nm thick) were synthesized and incorporated into organic polymeric thin films. The morphologies of these nanoshells were characterized with scanning and transmission electron microscopy. Powder X-ray diffraction demonstrated that the gold layers were highly crystalline. Thin films containing the gold nanoshells and polyethyleneimine were generated using dip-coating techniques based on electrostatic layer-by-layer self-assembly methods. Scanning electron microscopy was used to image the resultant composite films, which contained uniformly distributed gold nanoshells with limited aggregation. The optical properties were analyzed by absorption spectroscopy, revealing broad extinctions ranging from the visible to the near-IR spectral regions. X-ray photoelectron spectroscopy spectra were also obtained to determine the elements present and the oxidation states of these elements.