Targeted passivation via ammonium benzoate for suppressing deep-level defects of doctor-bladed CH3NH3PbI3 films

Abstract

Large-scale processing of perovskite solar cells (PSCs) with superior performance under air conditions is deemed as an inevitable trajectory for low-cost and efficient commercial manufacturing. Herein, a strategy of targeted passivation using ammonium benzoate (C7H7NO2) is developed to greatly enhance the power conversion efficiency (PCE) and stability of PSCs fabricated via large-area doctor-blading under air conditions. The conjunction of experimental and theoretical findings conclusively validates the strong interactions between the carboxylate group in C7H7NO2 and the Pb2+ within the perovskite structure. This not only effectively neutralizes deep-level defects in the CH3NH3PbI3 (MAPbI3) perovskite film but also significantly fortifies the stability of the perovskite lattice. Consequently, PSCs with a structure of ITO/SnO2/MAPbI3/Spiro-OMeTAD/Ag achieve an impressive efficiency of up to 22.78%. Meanwhile, the unencapsulated devices can maintain 92.4% of their initial efficiencies after aging for 840 h. Furthermore, doctor-bladed mini modules with an area of 1.6 and 9.5 cm2 exhibit PCEs of 19.73% and 18.62%, respectively.