Computational study of doping the 2D hybrid perovskite phenethylammonium lead iodide with Bi

Control over carrier type, carrier concentration, and Fermi level are critical in semiconductor technology and typically accomplished by doping. We study Bi as a potential dopant of the paradigmatic layered (so-called 2D) hybrid organic-inorganic perovskite phenethylammonium lead iodide ((PEA)2PbI4 or "PEPI"). Total-energy calculations (density-functional theory using the van der Waals corrected PBE functional) show that Bi can be incorporated either as a substitutional defect (dopant) or in conjunction with charge-compensating Pb vacancies (non-doping), depending on the synthesis conditions of a PEPI crystal. Energy band structure calculations using spin-orbit coupled hybrid density functional theory for supercell sizes above 750 atoms show that the energy levels introduced by Bi defects are found below the conduction band levels in the gap in either case. We compare the results to experimental findings including optoelectronic properties and photoelectron spectroscopy.