(164b) Electrochemical Crystallization On Nanoparticle-Decorated Electrodes

This paper describes electrocrystallization of charge-transfer tetrathiafulvalene (TTF) salts on highly oriented pyrolytic graphite (HOPG) electrode surface containing Au nanoparticles. The primary goal of the study is to examine the effect of nanoscale topographical features as provided by the Au nanoparticles on molecular ordering and crystallization. The secondary goal is to use Au nanoparticles to confine crystallization in order to make nanorod crystals. The electrodeposition of Au nanoparticles and TTF salt crystals is monitored by cyclic voltammetry (CV) and atomic force microscopy (AFM). The electrodeposition of Au nanoparticles on HOPG is found to be controlled by precursor ion concentration, applied potential, and pulse time. The electrocrystallization of (TTF)Br_0.76 on HOPG using 1-4 s potential pulse of 0.5V (vs. SCE) results in randomly oriented 1D crystalline rods in micro scale. However, the (TTF)Br_0.76 grow into nanorods on Au nanoparticle-decorated HOPG surface under the same electrochemical condition. The Au nanoparticles act as nucleation seeds to confine and induce (TTF)Br_0.76 nanorod crystal growth. The effect of Au nanoparticle size, Au nanoparticle coverage, and (TTF)Br_0.76 electrocrystallization conditions are investigated in order to obtain Au nanoparticle-(TTF)Br_0.76 hybrid nanostructures and understand the underlying mechanism. The electrocrystallization results contribute to the understanding of nanoparticle-mediated nucleation, previously studied using electrically inactive molecular compounds, and offer a new manufacturing route to nano-electrodes.