Characterization of Molecular Interaction in the Condensed Phase and at Interfaces by IR Spectroscopy
Subject Area Solid State and Surface Chemistry, Material Synthesis
Prof. Pucci - KIP, Uni HD
Layers of N-heteropolycycles and functional layer systems with such molecules are characterized by IR spectroscopy in a non-destructive manner. The quantitative determination of the complex dielectric tensor of the typically anisotropic systems is at the centre because this tensor is uniquely linked to the structure and the arrangement of the molecules and their electronic properties. So, molecular interactions, charge transfer, polaronic IR excitations, segregation in mixed systems, and degradation determine spectral details.
Our research results will improve the basic understanding of the molecular behaviour in the solid and at interfaces and thus serve to better control and optimize the semiconductor properties. For the characterization of inhomogeneous systems, the far-field IR spectroscopy will be completed by a modern near-field method with a lateral resolution down to 10 nm.
Figure 1: IR spectra taken during physical vapour deposition of TAPP-Br (TP A02) onto a flat gold layer (300 nm on mica) at room temperature under ultrahigh vacuum conditions at oblique incidence (83°) of p-polarized light. Reference is the bare gold layer. From an average thickness of about 0.5 nm on, one out-of-plane vibrational mode dominates the spectra, which indicates highly ordered layers. (Experiment by M. Tzschoppe and C. Huck, 2017).