Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 4: Perovskite and Photovoltaics I (joint session HL/KFM)
HL 4.7: Invited Talk
Monday, March 18, 2024, 11:15–11:45, EW 203
Influence of the Organic Cation Orientation on the Absorption Spectra of 2D Hybrid Organic-Inorganic Perovskites — •Svenja Janke — Department of Chemistry, University of Warwick, Coventry, UK
Hybrid organic-inorganic perovskites (HOIPs) allow combining organic and inorganic materials at the nanoscale and hence open up a wide area of tunability. In two-dimensional HOIPs, both organic and inorganic components can contribute to the electronic frontier levels. For the design of new devices like solar cells, a fundamental understanding of the electronic excitations, their photophysical signatures and the underlying atomic structure is essential. The 2D HOIP inorganic exciton binding energy depends approximately linearly on the inorganic band gap. To estimate the inorganic exciton contribution to the absorption spectrum, I benchmark the amount of Hartree Fock exchange in hybrid density functional theory calculations including spin-orbit coupling.
For the quaterthiophene-based 2D HOIP (AE4T)PbX4, variation of the halide anion leads to structural changes in the organic layer, causing changes in the absorption spectra. The bithiophene-based 2D HOIP (AE2T)PbI4 shows disorder along the stacking direction in X-ray scattering experiments, resulting in several possible atomic structural models for the organic component.
Here, I demonstrate that we can use a Frenkel-Holstein-Hamiltonian-based model to investigate how different orientations of the organic cation alter the organic and inorganic exciton contribution to the absorption spectrum.
Keywords: 2D hybrid organic inorganic perovskites; Absorption spectrum; Phenomenological model; Frenkel-Holstein Hamiltonian; Density Functional Theory