Abstract
Owing to the increasing popularity of lead-based hybrid perovskites for photovoltaic (PV) applications, it is crucial to understand their defect energetics and its influence on their optoelectronic properties. In this work, we simulate various point defects in pseudocubic structures of mixed iodide-bromide and bromide-chloride methylammonium lead perovskites with the general formula MAPbI3-yBry or MAPbBr3-yCly (where y is between 0 and 3), and use first-principles based density functional theory computations to study their relative formation energies and charge transition levels. We identify vacancy defects and Pb on MA antisite defect as the lowest energy native defects in each perovskite. We observe that while the low energy defects in all MAPbI3-yBry systems only create shallow transition levels, the Br or Cl vacancy defects in the Cl-containing pervoskites have low energy and form deep levels which become deeper for higher Cl content. We examine the structures and density of states of pure and defect-containing perovskite systems to obtain an understanding of the nature of defect levels. Further, we study extrinsic substitution by different elements at the Pb site in MAPbBr3, MAPbCl3, and the 50-50 mixed halide perovskite, MAPbBr1.5Cl1.5, and identify some transition metals that create lower energy defects than the dominant intrinsic defects and also create midgap charge transition levels.
Original language | English (US) |
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Pages (from-to) | 16729-16738 |
Number of pages | 10 |
Journal | Journal of Physical Chemistry C |
Volume | 124 |
Issue number | 31 |
DOIs | |
State | Published - Aug 6 2020 |
Funding
This material is based upon work supported by Laboratory Directed Research and Development (LDRD) funding from Argonne National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-06CH11357. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. We gratefully acknowledge the computing resources provided on Blues and Bebop, high-performance computing clusters operated by the Laboratory Computing Resource Center (LCRC) at Argonne National Laboratory.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Energy
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films