Berlin 2024 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Poster III

CPP 28.12: Poster

Mittwoch, 20. März 2024, 11:30–13:30, Poster C

Calculation of inter-molecular transition rates depending on structural parameters with DFTB — •Fabian Teichert¹, Robin Silligmann¹, Florian Günther^2,3, and Angela Thränhardt¹ — ¹Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany — ²Departamento de Física, Instituto de Geociências e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", Rio Claro, Brazil — ³Instituto de Física de São Carlos, Universidade de São Paulo (USP), São Carlos, Brazil

We investigate the transition rates of electrons between two organic molecules, expecially concerning thiophene and zinc porphyrine. For this, we calculate HOMO and LUMO states and energies, reorganisation energies and Hamiltonian coupling matrices with DFTB using the software dftb+. Based on these results, the transition rates are computed using Marcus theory for charge transfer. We present result for two systems: (1) two thiophene molecules and (2) two zinc porphyrine molecules. We show reorganisation energies, Hamiltonian coupling constants and transition rates dependent on the structural configuration. E.g. the thiophene molecules are shifted and rotated against each other. The final goal of our work is to obtain the statistical distribution of all the results due to the statistical fluctuation of the structure. This is suitable as input for subsequent Monte-Carlo hopping simulations, which can be used to describe the large-scale transport of charges within organic materials for e.g. solar cell applications.

Keywords: transition rate; charge transport; zinc porphyrine; density-functional-based tight binding (DFTB); Marcus transfer theory