Electrochemical charge injection into immobilized nanosized gold particle ensembles: Potential modulated transmission and reflectance spectroscopy

Self-assembled multilayer thin films of nanometer-sized gold particles link ed with organic dithiols have been prepared on glass, indium tin oxide, and gold substrates. The gold particles within these structures retain their i ntegrity and no sintering occurs as demonstrated by their optical absorbanc e, ellipsometry, and potential modulated transmission and reflectance spect roscopy. The optical response to electrochemical charge injection into the outermost layer of gold particles is completely different from that of bulk gold electrodes, and it is concluded that the particles have to be regarde d as discrete, immobilized quantum-dots.