Three-dimensional analysis of screen-printed electrodes by laser induced breakdown spectrometry and pattern recognition

Three-dimensional analysis of screen-printed electrodes was carried out by laser induced breakdown spectrometry and pattern recognition techniques. Surface characterisation was achieved by monitoring the plasma emission signals produced after target ablation by a pulsed Nd:YAG laser operating at 1064 nm. Two zones of the two-electrode system were tested, with a lateral resolution of 250 mum: zone I (working and reference electrodes, 6.25 mm x 6.25 mm) and zone II (electrical contacts, 6.25 mm x 3.25 mm). Distinct images were obtained by laser induced breakdown spectrometry (LIBS) from both the surface and in-depth distribution of carbon, gold, silver, platinum, palladium, titanium and aluminium. In addition, the techniques known as principal component analysis (PCA) and cluster analysis (CA) were used to classify the spectral information provided by all the components in order to obtain two-dimensional plots of the sample composition. (C) 2001 Elsevier Science B.V. All rights reserved.