Self-assembly of organic molecules within oxide nanostructures

• Applicant: Professorin Dr.-Ing. Manuela S. Killian
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Coating and Surface Technology
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 410554859

In this project we will overcome current problems in loading and especially in the characterization of interlaced organic-inorganic nanostructures. We will produce homogeneous and heterogeneous distributions of organic self-assembled monolayers (SAMs) within oxide nanostructures and develop reliable characterization methods for the analysis of the depth distribution of the SAMs. The analysis of such organic-inorganic composite materials, in particular the depth distribution of multiple organic SAMs, is challenging. Many techniques cannot provide this information, as they either lack depth resolution, sensitivity or chemical information. With time-of-flight secondary ion mass spectrometry (ToF-SIMS) we are able to distinguish similar SAMs adsorbed to (even low-conductivity) surfaces. In this project, we will apply a combination of shallow focused ion beam (FIB) milling and ToF-SIMS imaging to obtain artefact free chemical maps of the depth distribution of organic molecules within metal oxide nanostructures.Our goal is to develop metal oxide nanostructures, such as vertically oriented nanopores and nanotubes, nanosponges or nanoparticle layers, which are coated with SAMs of functional organic molecules either homogeneously over the entire nanostructure depth or at selected positions. We aim at the development of complex, multifunctional architectures by selective modification of distinct depths of the structures. Nanostructures of the oxides of Zr, W and Sn will be in the focus of this project. The generation of porosity and length adjustable oxide layers on both metallic and transparent substrates are included in the proposed research.In addition to the modification with SAMs, we aim at the defect-free filling of oxide nanostructures with polymers. The filled structures will additionally be applied either in perovskite solar cells as hole transporting material (HTM, particularly tungsten oxide) and electron transporting layer (ETL, particularly tin oxide), or in drug release systems (zirconia). Furthermore, polymer filling of the nanostructures will be used for artefact-reduced conventional depth profiling and to protect the SAMs within the nanostructured oxides during analysis.

• DFG Programme: Research Grants
• International Connection: Belgium
• Cooperation Partner: Professorin Dr. Annabel Braem