Angstrom-Resolved Interfacial Structure in Buried Organic-Inorganic Junctions

Charge transport processes at interfaces which are governed by complex interfacial electronic structure play a crucial role in catalytic reactions, energy storage, photovoltaics, and many biological processes. Here, the first soft X-ray second harmonic generation (SXR-SHG) spectrum of buried interface (boron/Parylene-N) is reported. SXR-SHG shows distinct spectral features that not observed absorption spectra, demonstrating its extraordinary sensitivity. Comparison to calculations indicates boron-organic separation distance 1.9 {\AA}, wherein changes as small 0.1 {\AA} result easily detectable shifts (ca. 100s meV). As inherently ultrafast sensitive individual atomic layers, it creates possibility study variety processes, e.g. catalysis, with time resolution bond specificity.