Barium acetate as an additive for high performance perovskite solar cells

Defects within the halide perovskite films limit the efficiency and stability of perovskite solar cells (PSCs). Here, barium acetate (BaAc₂) is employed as an additive in MAPbI₃ for high performance PSCs. The BaAc₂ can control the crystallization and thus produce high-quality perovskite films, which is attributed to interaction between the acetate ions and perovskite precursor. Both low defect density and the movement of energy levels contribute to a significant increase in open circuit voltage (V_oc). Consequently, an efficiency up to 19.82% with a high V_oc of 1.13 V is obtained based on the optimized BaAc₂ concentration device. Moreover, the compact perovskite crystal with suppression of ion migration endows the BaAc₂ doped PSCs with obviously enhanced thermal stability. The device with BaAc₂ additive maintained over 90% of its original power conversion efficiency (PCE) after thermal aging at 90 °C for 400 hours.