2D lead free Ruddlesden-Popper phase perovskites as efficient photovoltaic materials: A first-principles investigation

Abstract

Though lead halide perovskites hold impressive optoelectronic properties, because of the bottleneck of lead toxicity, searching for the lead free perovskites is highly demanding for their commercial applications in the optoelectronic devices. Alongside of the lead free perovskites, two dimensional (2D) organic–inorganic hybrid halide perovskites (OIHHPs) are getting great attention as photovoltaic materials due to their air stability over the three dimensional(3D) counterpart and high performance. Herein, we have investigated recently synthesized lead free 2D Ruddlesden-Popper (RP) phase OIHHPs (X-PEA)2SnI4 (PEA=phenylethylammonium and X=H, para-F, meta-F, ortho-F) along with (PEA)2Sn1−xGexI4 where x = 0.5 and 1. Here studied all perovskites are direct band gap semiconductors with band gap in the solar energy region with high absorption coefficients. We have calculated the charge carrier effective masses along X–Γ–X and Y–Γ–Y and finally we have estimated maximum theoretical photoconversion efficiency (PCE) for all which reaches up to 25.58% making them suitable for their applications in high performance photovolatic devices.