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HL: Fachverband Halbleiterphysik
HL 12: Heterostructures, Interfaces and Surfaces: Photonics
HL 12.6: Vortrag
Montag, 9. März 2026, 18:00–18:15, POT/0051
Correlative Atomic Force Microscopy to Understanding Local Charge Transport in Photoanodes — •Sven Doll and Johanna Eichhorn — Technical University of Munich, Garching, Germany
Efficient photosystems for solar-to-chemical energy conversion are often based on nanostructured semiconductor architectures. In these material systems, the nanoscale properties frequently dominate the performance at the macroscale. Therefore, local understanding of their charge transfer and transport properties is decisive for optimizing their efficiency and stability.
To this end, we correlate Kelvin probe force microscopy (KPFM) and (photo)conductive atomic force microscopy (AFM) to study the local band bending, charge accumulation, as well as variations in the generated surface photovoltage and (photo)conductivity. However, analyzing nanostructured materials with complex morphologies is not trivial, because effects such as topographic crosstalk can significantly influence the results obtained. To overcome these issues, we leverage 2nd eigenmode and heterodyne KPFM measurements with improved resolution and sensitivity compared to conventional tapping mode KPFM techniques. For BiVO4, one of the most extensively studied metal oxide photoanode materials, we compare different KPFM modes and correlate the results with local conductivity measurements to gain insights into local semiconductor properties at grain boundaries or different crystal facets. Overall, the gained nanoscale insights will put forward the development of rational design strategies to enhance the macroscale durability and efficiency of solar energy conversion systems.
Keywords: AFM; KPFM; conductive AFM; BVO