Development and atomic and electronic structure characterization of functional Sn/SnOx surfaces for SERS-based misfolded protein analysis

• Applicants: Dr. Tanja Deckert-Gaudig; Dr. Vladimir Sivakov
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448666227

The inherent advantages of nanostructured materials can be improved by combining two phases with distinct properties. In the framework of the proposed bilateral GER-RUS research project we will develop Tin(Sn)-based nanocomposites to produce such materials. Functional Sn-based nanostructures embedded in a SiNWs matrix have some advantages and offer attractive options due to their chemical and mechanical stability, low cost production and improved optical and catalytic properties. In this respect, the targeted scientific breakthrough of the proposed project will be the controlled growth of Sn-layers on nanostructured silicon and quartz surfaces for biophotonics applications. The local electric field enhancement factor of the plasmonic nanostructures and the surface stability of Sn/SnOx substrates produced by chemical or physical vapor deposition techniques have not been studied yet. For this reason, the long-term stability and surface composition characterization are highly important, especially with regard to the development of new application strategies. For the formation of the proposed surfaces, chemical vapor deposition using tin(II) and tin (IV) volatile alkoxide precursors and metallic tin magnetron sputtering followed by additional thermal treatment will be applied. The characterization of the obtained structures will be performed with various surface sensitive methods. The results will be complemented by theoretically modeling growth processes and plasmonic properties. Thereby, an optimized procedure for Sn/SnOx surfaces will be developed and established. A precise and detailed analysis of the atomic and electronic structure as well as the physico-chemical state of the formed structures will be achieved by using the following techniques: XANES (X-ray Absorption Near Edge Structure), XPS (X-ray Photoelectron Spectroscopy) and PEEM (Photo Emission Electron Microscopy) using large-scale facilities at BESSY II synchrotron storage ring and at National Research Center «Kurchatov Institute». Additionally, USEXES (Ultrasoft X-ray emission spectroscopy) will be applied to characterize the silicon matrices with unique non-destructive depth profiling. All methods will be applied in surface and bulk sensitive modes supplemented by computer modeling and electronic structure ab-initio calculations of the most important possible phases. In the proposed bilateral research project, Sn/SnOx substrates will be exploited in surface-enhanced Raman spectroscopy experiments on protein-related compounds. Using excitation laser wavelengths in the visible down to the deep-UV spectral region, the achieved spectroscopic data will provide new insights into the molecular structures of amyloid fibrils and their precursors.

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research, until 3/2022
• Cooperation Partner: Professor Dr. Sergey Turishchev, until 3/2022