GW Band Structures and Carrier Effective Masses of CH3NH3PbI3 and Hypothetical Perovskites of the Type APbI3: A = NH4, PH4, AsH4, and SbH4

Solar cells based on organic inorganic lead halide perovsldtes are currently one of the fastest improving photovoltaic technologies. Understanding the fundamental electronic and optical properties of CH3NH3PbI3 and related metal halide perovsldtes represents a key step in the future development of perovskite optoelectronic devices. Here we study the quasipartide band structures, band gaps, and effective masses of CH3NH3PbI3 and the hypothetical perovskites NH4PbI3, PH4PbI3, AsH4PbI3, and SbH4PbI3 within the GW method, using Wannier interpolation. We find that the quasipartide band gaps of the hypothetical perovskites decrease as the size of the cation increases, obtaining values of 1.9 eV (NH4PbI3), 1.8 eV (PH4PbI3), 1.6 eV (AsH4PbI3), and 1.4 eV (SbH4PbI3). The same trend is followed also by the electron and hole effective masses of these compounds, all of which have values below 0.3 electron masses. By estimating the ideal short-circuit current, the open-circuit voltage, and the theoretical limit for the power conversion efficiency of a solar cell based on these compounds, we find that PH4PbI3, AsH4PbI3, and SbH4PbI3 could improve the performance of solar cells based on CH3NH3PbI3.