Showing papers by "Ligia Maria Moretto published in 2008"
TL;DR: Electrochemistry and luminescence methods were exploited to obtain information on the electrochemical activity and homogeneity of Nafion Langmuir-Blodgett films, and experimental evidence and calculations indicate that lowering of the film thickness down to the nanometric level is very effective in shortening the switching time.
Abstract: A combination of electrochemistry and luminescence methods was exploited to obtain information on the electrochemical activity and homogeneity of Nafion Langmuir−Blodgett films. The redox behavior of the Ru(bpy)32+ probe incorporated in the Nafion film was monitored by epifluorescence microscopy. The photoluminescent images, recorded by a charge-coupled device (CCD) camera, reflect the distribution of the probe in the film, which resulted as very uniform, particularly in comparison with spin-coated films. Apparent diffusion coefficients (Dapp) determined by cyclic voltammetry for films of less than 10 layers are in the range of 1 × 10−12 to 8 × 10−12 cm2 s−1, that is, 2 orders of magnitude lower than values reported in the literature for spin-coated Nafion films. The application to the electrode of a potential able to oxidize the luminescent Ru(bpy)32+ to the nonluminescent Ru(bpy)33+ switched off the photoluminescence with a response time that for the LB films was much shorter than that for the spin-coat...
31 citations