LAUSR

Abstract In this investigation, in an effort to explore non-lead and inorganic perovskite solar cells (PSCs), we have simulated a Cs3Bi2I9 perovskite device utilizing a suite of various electron and hole transport layers (ETLs and HTLs). A maximum power conversion efficiency (PCE) of 13.82 % (open-circuit voltage Voc of 0.92 V, short-circuit current Jsc of 22.07 mA/cm2, and fill factor FF of 68.21 %) is obtained at 1400 nm Cs3Bi2I9 layer thickness for an optimized device with TiO2 as the ETL and NiO as the HTL. For the choice of ETL and HTL, the parameters with the highest impacts on device performance include layer band alignment (conduction and valence band offsets with respect to perovskite band edges), electron affinity, charge mobilities and density of states. We further demonstrate that modulating radiative recombination rate is not significantly impactful on the device PCE, highlighting an improvement of 0.38 % for a 1000X improvement in the rate; however, impacts on Voc due to absorber layer thickness variation do showcase an optimal behavior, thus highlighting the role of charge recombination and losses on device performance. Lastly, we showcase that Cs3Bi2I9 is more sensitive to defect density compared to the ETL and HTL. For a device with defects in the perovskite only (with ETL and HTL defect-free) a PCE decrease from 13.1 % (with defect density of 1 × 1010  cm−3) to 11.16 % (with defect density of 1 × 1016  cm−3) is shown, together with a sharp fall noticed after 1 × 1015  cm−3.