CRC 1772/1: Nanoscale optical imaging and spectroscopy of mol2Dmat heterostructures (SP B02)

The project studies the effect of nanoscale features of the 2D material/molecule interface on intercalation, charge transfer, and emergent excitons in mol2Dmat heterostructures using tip- enhanced Raman and photoluminescence spectroscopies. We will exploit the high spatial resolution (25 nm) enabled by our newly installed setup for tip-enhanced Raman spectroscopy to study how local structural inhomogeneities affect charge transfer in a variety of heterostructures, including polyhalides intercalated in bilayer graphene and transition metal dichalcogenides interfaced with strong donor/acceptor molecules. We will focus, in particular, on the role of defects in 2D material heterostructure templates and develop procedures to distinguish localized defect excitons from mobile charger-transfer excitons. We will map out the spatial diffusion of CTEs directly by tip- enhanced PL spectroscopy with displaced excitation with the goal of determining the nature of these excitons and their potential use as information carriers in optoelectronics. The nanoscale imaging and spectroscopy performed here will provide protocols for the interpretation of diffraction-limited photoluminescence and Raman measurements across the CRC.