Nanostructured oxides are coated with self-assembled monolayers (SAMs) of functional organic molecules or filled with organic materials (e.g., polymers, drug molecules)  for various applications, reaching from solar energy conversion to catalysis or medical applications. One example are recently developed solar capsules, encapsulated dye sensitized solar cells based on titanium dioxide nanotubes.[1] A second example are zirconia nanotubes designed for local, triggered drug release from implant surfaces.[2] These hybrid materials consist of a porous, inorganic oxide matrix that is modified or filled with organic compounds. However, we still lack control and understanding about the depth distribution of SAMs within the nanostructures. The analysis of the distribution of the organic compounds within the inorganic porous material is challenging, as a range of artefacts may occur during the sample preparation for analysis, or the analysis itself. To overcome these issues in depth-resolved characterization of hybrid organic-inorganic nanostructures, this study compares the possibilities given by the use of time-of-flight secondary ion mass spectrometrry (ToF-SIMS) alone and in combination with cross-section-polishing (CSP) and focused-ion-beam (FIB) cuts.

REFERENCES
[1]     P. Hartwich, S. Naidu Vakamulla Raghu, C. Pritzel, M.S. Killian, “Preparation and characterization of encapsulated dye sensitized solar cells”, submitted.
[2]     S. Naidu Vakamulla Raghu, G. Onyenso, S. Mohajernia, M.S. Killian “Functionalization strategies to facilitate multi-depth, multi-molecule modifications of nanostructured oxides for triggered release applications”, Surf. Sci. 2022, 719, 122024, doi: 10.1016/j.susc.2022.122024.