We investigated the change in Si surface recombination behaviour during the electrodeposition of ultrathin polypyrrole (PPy) films onto Si surfaces by means of in-situ pulsed photoluminescence (PL) spectroscopy. The quenching of the band-gap related PL is lower (better passivation) when the electrodeposition is performed in a less acidic solution by use of potential pulse sequences. In-situ infrared spectroscopic ellipsometry (IR-SE) was applied for the first time to PPy electrodeposition. IR-SE and PL measurements confirm negligible formation of SiO x species at the Si/PPy interface although aqueous electrolytes were used.
Two different methods were used to immobilise gold nanoparticles on ultrathin films of polythiophene and polythiophene derivatives. The first method utilised ultrathin films of polythiophene to prepare gold nanoparticles by direct reduction of HAuCl 4 . A uniform coverage of the polythiophene films with randomly distributed gold nanopraticles possesing a polydisperse size distribution was obtained. Size and size distribution of the gold nanoparticles could be controlled by time, concentration of Au 3+ , and the addition of a cosolvent. With the second method, ultrathin films of polythiophene de-
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