Prof. MARTIN VÁCHA
Nanoscale and single-molecule spectroscopy of conjugated polymers, perovskite materials and related systems
Department of Materials Science and Engineering, Tokyo Institute of Technology
The talk will introduce the use of single-molecule spectroscopy on several systems, including conjugated polymers, supramolecular fibers and rings, and perovskite nanocrystals and film. Simultaneous force and fluorescence spectroscopy on single chains of polyfluorene reveals spectral changes resulting from the chain stretching, as well as optomechanical force due to intrachain aggregate coupling. Supramolecular systems are studied with the aim of understanding the factors responsible for long-range exciton transfer which has been observed on molecular nanofibers. Nanoscale spectroscopy on mixed-cation perovskite films reveals local compositional heterogeneity as well as blinking synchronized over micrometer distances, indicating efficient charge migration across grain boundaries. Inorganic perovskite nanocrystals are studied in complexes with metal organic frameworks where real-time formation and growth of the nanocrystals is monitored.