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 perovskites are currently one of the fastest improving photovoltaic technologies. Understanding the fundamental electronic and optical properties of CH 3 NH 3 PbI 3 and related metal halide perovskites represents a key step in the future development of perovskite optoelectronic devices. Here we study the quasiparticle band structures, band gaps, and effective masses of CH 3 NH 3 PbI 3 and the hypothetical perovskites NH 4 PbI 3, PH 4 PbI 3, AsH 4 PbI 3, and SbH 4 PbI 3 within the GW method, using Wannier interpolation. We find that the quasiparticle band gaps of the hypothetical perovskites decrease as the size of the cation increases, obtaining values of 1.9 eV (NH 4 PbI 3 ), 1.8 eV (PH 4 PbI 3 ), 1.6 eV (AsH 4 PbI 3 ), and 1.4 eV (SbH 4 PbI 3 ). 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 PH 4 PbI 3, AsH 4 PbI 3, and SbH 4 PbI 3 could improve the performance of solar cells based on CH 3 NH 3 PbI 3 .