A direct and facile synthetic route for micron-scale gold prisms and fabrication of gold prism thin films on solid substrates

Flat gold prisms that have micrometer-scale edge length and nanometer-scale thickness (micro-prisms, as defined by edge length of prisms) were synthesized through a facile solution-phase synthetic method. Two effective measures were adopted in order to prepare the well-defined micro-prisms: (i) selecting poly(N-vinylpyrrolidone)(PVP) as the shape-directing agent to induce the preferential growth of small gold nanocrystals and (ii) using a weak reducing agent, ethylene glycol (EG), to slow down the reduction rate of AuCl4− ions. Besides, the light played an important role in inducing the formation of tiny nanoprisms in the early stages of Au(III) ion reduction. Considering that gold nanoclusters have a strong tendency to heterogeneous nucleation at solid/liquid interfaces followed by the preferential planar growth, gold prism thin films were thus fabricated on glass substrates.