| Autor: |
Chen Y; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K., Motti SG; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K., Oliver RDJ; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K., Wright AD; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K., Snaith HJ; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K., Johnston MB; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K., Herz LM; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K.; Institute for Advanced Study, Technical University of Munich, Lichtenbergstrasse 2a, D-85748 Garching, Germany., Filip MR; Department of Physics, University of Oxford, Clarendon Laboratory, OX1 3PU Oxford, U.K. |
| Abstrakt: |
Halogen mixing in lead-halide perovskites is an effective route for tuning the band gap in light emission and multijunction solar cell applications. Here we report the effect of halogen mixing on the optoelectronic properties of lead-halide perovskites from theory and experiment. We applied the virtual crystal approximation within density functional theory, the GW approximation, and the Bethe-Salpeter equation to calculate structural, vibrational, and optoelectronic properties for a series of mixed halide perovskites. We separately perform spectroscopic measurements of these properties and analyze the impact of halogen mixing on quasiparticle band gaps, effective masses, absorption coefficients, charge-carrier mobilities, and exciton binding energies. Our joint theoretical-experimental study demonstrates that iodide-bromide mixed-halide perovskites can be modeled as homovalent alloys, and local structural distortions do not play a significant role for the properties of these mixed species. Our study outlines a general theoretical-experimental framework for future investigations of novel chemically mixed systems. |
