Multilayer hybrid films of titania semiconductor nanosheet and silver metal fabricated via layer-by-layer self-assembly and subsequent UV irradiation

Interesting multilayered nanostructures of molecular-scale alternating titania nanosheet and silver metal have been successfully fabricated by combined use of a layer-by-layer route and an in situ room-temperature ultraviolet irradiation technique with a titania nanosheet and a polyethylenimine - Ag+ (PEI-Ag+) complex as the electrostatic building blocks. The consecutive buildup of the PEI/Ti1-delta O2/(PEI-Ag+/Ti1-delta O2)(n-1) film was monitored by UV-vis absorption spectroscopy. The nearly linear increase in absorbance as a function of the sequential assembly number for the multilayer film indicates that almost same amount of materials was deposited in each dipping cycle. The tunable repeating ordered structure of titania nanosheet-silver multilayer films can be obtained by varying the concentration ratio of Ag+ to the repeating unit of PEI, essential for meeting the demands on the diverse application of the multilayer films.