Donor doping of CsPbBr₃

The inorganic lead halide perovskite CsPbBr₃ exhibits many outstanding properties, in addition to potentially offering environmental stability better than its hybrid perovskite counterparts. The full utilization of this material in optoelectronic applications would be aided by gaining the ability to control the electrical conductivity via impurity doping. One possible donor, bismuth, has been found to enhance solar cell efficiency, and an increase in the position of the Fermi level upon doping. Here I examine how bismuth incorporates into CsPbBr₃ using first-principles hybrid density functional theory. The stability of different configurations is considered as a function of chemical potential and Fermi level. Although bismuth prefers to substitute for lead under most conditions, it introduces a deep donor level ~500 meV from the conduction-band minimum, indicating it will not efficiently generate free carrier concentrations. Based on these results, donor-doping strategies for CsPbBr₃ are reconsidered.