Localized surface plasmon resonances in heavily doped (degenerated) semiconductor and oxide nanocrystals prepared by colloid chemistry

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The appearance of so-called localized surface plasmon resonances (LSPRs) is nowadays a well-known and well investigated phenomenon in noble metal nanoparticles. Due to this fascinating physical effect a variety of research and application fields arises including nanooptics, fluorescence enhancement, surface enhanced Raman spectroscopy (SERS), plasmon assisted sensing and many more. However, hardly any alternatives to noble metal materials have been suggested for LSPR exhibiting nanoparticles yet, which limits the spectral operation regime and goes along with high material costs. In order to address this scientific lack, the project aims at the synthesis and characterization of a new class of plasmonic nanocrystals, namely of heavily doped metal oxide and semiconductor nanocrystals with plasmonic properties. For this purpose, synthetic routes to heavily self-doped semiconductor nanomaterials like Cu(2-x)Se will be developed, in addition to the development of synthetic pathways to heavily doped nanocrystals from zinc oxide and tin oxide. Furthermore, especially for these new materials, it is expected that a control over the chemical and dielectric environment of the nanoparticles is crucial in order to alter or stabilize the plasmonic properties of the nanocrystals. Therefore, fine tuning of the LSPR frequencies will be achieved by developing and executing post synthetic treatments such as shell growth and ligand exchange. Finally, this new type of plasmonic nanoparticles will be investigated with respect to the possibility to replace or complement commonly used gold (and other noble metal) nanoparticles in LSPR based sensory applications on a model system. A positive result might possibly give rise to an alternative (or complementary) class of plasmonic nanomaterials and hence to a new family of nanoparticles applicable in plasmonic sensory systems.