New approaches for elemental analysis of advanced solid materials using laser-assisted plasma spectrochemistry.

Abstract

To face the challenges of the 21 st century, material science has made tremendous progress in the last years. To tailor materials for their intended application, it is crucial to understand the relationship between the composition of the material and the desired properties. One of the most promising techniques for the analytical characterization of solid materials, that have gained attention in recent years are the ones based on laser-assisted plasma spectrochemistry. One of the main challenges in the direct-solid analysis remains quantification. A central aspect of this thesis is the development of methods to circumvent the need for matrix-matched standards. To determine the stoichiometry of boride thin-films, methodologies based on self-aliquoting microgrooves and dried droplets in conjunction with LA-ICP-MS and LIBS were established. Therecently introduced online-LASIL system was further enhanced and employed to overcome the depth resolution limits of conventional LA-ICP-MS. With this, the platinum surface decoration on fuel cell cathodes was successfully quantified. The capability of online-LASIL to perform quantitative depth profiles employing liquid standards was used to study the oxidation behavior of silicon-doped boride materials. The last topic of this work is related to the analysis of fluorine, an element that is not accessible with most methods used for the analysis of solid samples. Using molecular LIBS, it was for the first time possible to spatially resolve the distribution of fluorine in an artificial polymer sample.Using the findings in this thesis, it is possible to enhance the applicability of laser ablation based methods to a broad spectrum of material-science-related questions. The presented methods can easily be adapted to other material systems of interest.