Lead (Pb) management in the entire life cycle of highly efficient and stable perovskite solar cells

Abstract

Lead (Pb) related issues severely affect the entire life-cycle of perovskite solar cells (PSCs) which include Pb-related defects during preparation, photolysis of excessive PbI₂ during the operation and Pb²⁺ leakage from the damaged PSCs towards the end of their lifecycle, consequently hindering the commercialization of PSCs. Herein, a novel yet facile Pb-management strategy has been proposed to alleviate the Pb-related issues by incorporating benzophenone (BP) additives, namely BP-5 and BP-9, in the perovskite layer. The resultant PSCs showed excellent efficiency (25.47%) and stability by successfully passivating Pb-related defects, suppressing the formation of the δ-FA phase, sustainably absorbing the ultraviolet (UV) and forming water-insoluble Pb²⁺ complexes to limit the Pb leakage. The devices retained 96% and 91.15% of their initial efficiency after 600 h and 1000 h of UV aging test and operational test, respectively. Moreover, the addition of BP-9 effectively suppressed Pb²⁺ leakage by 93.5%. Despite its simple approach, the proposed strategy has successfully addressed Pb related issues spanning over the entire life-cycle of the PSCs.