Numerical simulation studies of a fully inorganic Cs2AgBiBr6 perovskite solar device

Abstract With perovskite solar cell (PSC) technology on the brink of commercialization, the use of lead and degradable components remain a concern. We have carried out simulation studies to explore a non-toxic and inorganic device utilizing Cs2AgBiBr6 as the active layer and Cu2O as the hole transport layer (HTL). A maximum power-conversion efficiency (PCE) of 7.25% (open-circuit voltage Voc of 1.5V, short-circuit current Jsc of 11.45 mA/cm2, and fill factor FF of 42.1%) was obtained at an optimal perovskite layer thickness of 600 nm. Our investigation further reveals that with increasing perovskite thickness, as J0 (saturation current) decreases, Voc increases. By varying radiative recombination rate, we report out a maximum PCE of 8.11% at a 10X lower than usual rate. A conduction band offset of 0.1 eV between the TiO2 electron transport layer (ETL) and the active layer and a valence band offset of 0.35 eV between the active layer and the HTL produce optimal PCE values of 7.31% and 11.17% respectively. Lastly, we demonstrate that Cs2AgBiBr6 is more sensitive to defect density than the HTL and ETL by a factor of 100. Overall, our results are encouraging and insightful, providing guidance towards fabricating a non-toxic and inorganic perovskite solar device.