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

所谓的局部表面等离子体共振（LSPRs）的出现是目前贵金属纳米粒子中一个众所周知的和研究得很好的现象。由于这种迷人的物理效应，出现了各种研究和应用领域，包括纳米光学，荧光增强，表面增强拉曼光谱（SERS），等离子体辅助传感等等。然而，几乎没有任何贵金属材料的替代品被建议用于展示纳米粒子的LSPR，这限制了光谱操作制度，并伴随着高材料成本。为了解决这一科学缺陷，该项目旨在合成和表征一类新的等离子体纳米晶体，即重掺杂金属氧化物和具有等离子体特性的半导体纳米晶体。为此，除了开发从氧化锌和氧化锡合成重掺杂纳米晶体的合成途径外，还将开发合成重掺杂半导体纳米材料（如Cu(2-x)Se）的途径。此外，特别是对于这些新材料，为了改变或稳定纳米晶体的等离子体特性，预计对纳米颗粒的化学和介电环境的控制是至关重要的。因此，LSPR频率的微调将通过开发和执行合成后处理，如壳生长和配体交换来实现。最后，这种新型等离子体纳米粒子将在模型系统上取代或补充基于LSPR的传感应用中常用的金（和其他贵金属）纳米粒子的可能性。一个积极的结果可能会产生一种替代（或补充）的等离子体纳米材料，从而产生一种适用于等离子体感觉系统的新纳米颗粒家族。

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.