Excited State Dynamics in 2D Perovskite Thin Films: Roles of Surface Ligands
Daniel Ramirez1, Talgat M. Inerbaev2 Dmitri Kilin1
1Department of Chemistry and Biochemistry, North Dakota State University Fargo, 2ENU, KZ
Lead-Halide Perovskites are being studied vastly due to their favorable optoelectronic properties when compared to conventional devices today1,2. The single-crystalline hybrid perovskites have important photoelectronic properties for semiconductor devices, such as solar cells and light emitting diodes3,4. Here we implement a first principle study to identify and analyze dependence of optoelectronic properties of Cesium Lead Bromide perovskite, (CsPbBr3) on composition, quantum confinement, and surface morphology. The calculations include a combination of ground state electronic structure modeling by DFT and dynamics modeling of excited state. The dynamic of excited states is modeled via the Redfield equation of motion for electronic degrees of freedom and are parameterized by nonadiabatic couplings, i.e. response of electronic states to thermal dynamics of nuclei. Specifically, we model the dynamics of photoinduced electronic state at the surface of 2D quantum confined thin films of perovskite depends on presence or absence of different adsorbates and symmetry of exposed crystallographic surface. By analyzing dynamics of charge redistribution between inner area of thin film of the perovskite and surface defects we can identify mechanics between radiative and nonradiative recombination pathways, and, thus, quantum yield of photoluminescence. The obtained results allow for theory-guided design of optimal morphology of 2D perovskite films for light emitting applications.
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