SKM 2021 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 8: Poster Session II

HL 8.26: Poster

Dienstag, 28. September 2021, 10:00–13:00, P

Halogen vacancy migration at a surface of CsPbBr3: Insights from Density Functional Theory — •Raisa-Ioana Biega¹ and Linn Leppert^{1, 2} — ¹Institute of Physics, University of Bayreuth, Bayreuth 95440, Germany — ²MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands

Migration of mobile halogen ions is ubiquitous in lead-halide perovskites, and has been studied in detail experimentally and with computational modelling techniques. However, the question whether and how surfaces affect ion migration in these materials is still debated. Here we contribute to this debate by using density functional theory to compute bromine vacancy migration in the bulk and at the (001) surface of cubic CsPbBr3. We find that the migration barrier at the surface is approximately half of that in the bulk due to larger structural distortions at the surface. The targeted choice of an alkali-halide passivation layer can suppress this undesirable effect and leads to an increase of migration barrier to almost the bulk value.