Enhanced electrochemistry of nanoparticle-embedded polyelectrolyte films : interfacial electronic coupling and distance dependence

Factors affecting the interfacial electronic communication attributed to the enhanced solution electrochemisty observed at electrodes modified with hybrid nanoparticle-polyelectrolyte (NP- PE) film assemblies was systematically investigated. Specifically, the faradaic current and voltammetric peak splitting recorded for cyclic voltammetry of ferricyanide redox species (Fe(CN)63-/4- ) at films constructed from various architectures of citrate-stabilized gold NPs (CSNPs) embedded in polyelectrolyte films composed of poly-L-lysine (PLL) and poly-S-styrene (PSS) were used to establish the relative importance of both distance and electronic coupling an and electrode-solution interface as well as an interparticle phenomenon. Layer-by- layer construction of NP-PE films allowed for the position and density of NPs to be varied within the film. The cumulative results observed at these films suggest that while distance dependence prevails in nearly every case and interparticle coupling can contribute to facilitating the Fe(CN)63-/4- electrochemistry, interfacial electronic coupling of the PE-NP films is of critical importance with decoupling easily achieved by disengaging NP-electrode interactions