Lead acetate as a superior lead source enables highly efficient and stable all-inorganic lead-tin perovskite solar cells

Lead iodide (PbI2) has been commonly used as the lead source of all-inorganic Pb-Sn perovskite solar cells (PSCs), however it is hard to obtain phase-pure Pb-Sn perovskite films with specific composition. Herein, lead acetate (Pb(Ac)2) was applied as an alternative lead source substituting PbI2, affording homogeneous phase-pure CsPb0.4Sn0.6I2.4Br0.6 films, delivering a certified power conversion efficiency (PCE) of 13.88%, which is the highest value among all-inorganic Pb-Sn PSCs reported up to now.