BCCMS  /  Groups  /  CMS  /  People - Bremen  /  M. Madjet
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Fields of interest

Photo-induced processes in Energy Materials

PublicationsGoogle Scholar

Research

Energy and charge transfer processes in photosynthetic complexes and in various materials for energy applications. Light-matter interactions: investigating electronic processes in materials triggered by the interaction with light with a main focus on applications in photochemistry, photovoltaics and sensors. Develop and adapt codes to address different Chemical and Physical processes. Screening organic molecules for organic redox flow battery applications. Investigation of the effect of the functional groups on the electrochemical activity of carbon-based electrode for vanadium flow battery applications.

Neutral C60 is well known to exhibit a giant resonance in its photon absorption spectrum near 20 eV. This is associated with a surface plasmon, where delocalized electrons oscillate as a whole relative to the ionic cage. Absolute photoionization cross-section measurements for C60+ , C602+, and C603+ ions in the 17– 60 eV energy range show an additional resonance near 40 eV. Time-dependent density functional calculations confirm the collective nature of this feature, which is characterized as a dipole-excited volume plasmon made possible by the special fullerene geometry.

The success of organic−inorganic perovskites in optoelectronics is dictated by the complex interplay between various underlying microscopic phenomena. The structural dynamics of organic cations and the inorganic sublattice after photoexcitation are hypothesized to have a direct effect on the material properties, thereby affecting the overall device performance. Here, we use ultrafast heterodyne-detected two-dimensional (2D) electronic spectroscopy to reveal impulsively excited vibrational modes of methylammonium (MA) lead iodide perovskite, which drive the structural distortion after photo-excitation.