(160c) Monolayer Alkylamine-Gold Nanoparticle Films with Tunable Electrical and Optical Properties

Two-dimensional (2D) monolayer nanoparticle films display collective properties that are different from single nanoparticles and the corresponding bulk materials, making them of interest for photovoltaics, light emission, sensing, and many electronic applications. These properties depends not only on the particle size and shape, but also on the ensemble ordering, and interparticle distance. Here, we demonstrate that 2D monolayer gold nanoparticle (Au NP) films can be formed at the hexane/water interface, with interparticle separation tunable via the alkylamine chain length. To preserve the 2D NP film integrity, a ‘drain-to-deposit’ strategy is used to transfer the film from the water/hexane interface to a solid substrate. Both the surface plasmon resonance (SPR) and the electrical conductivity of the films show a strong dependence on particle spacing. To the best of our knowledge, this is the first systematic study of the optical properties and electrical conductivity of monolayer Au NP films tuned by alkylamine chain length. This approach allows the precise control of interparticle spacing over large-area NP films. The demonstrated self-assembly of the 2D NP superlattice could have an impact on the manufacture of high performance optical and electronic devices.