Numerical simulation studies of a fully inorganic Cs₂AgBiBr₆ perovskite solar device

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.