Dual Interface Passivation With Multi‐Site Regulation Toward Efficient and Stable Inverted Perovskite Solar Cells

The implementation of a dual interfacial passivation approach through thermal annealing with 2,6-pyridinedicarboxylic acid chloride (PAC) successfully coordinated the undercoordinated Pb²⁺ and I⁻ ions in perovskite crystals. This process substantially suppressed defect state density in the material system while simultaneously improving energy level alignment and promoting efficient charge carrier extraction.

Abstract

The rapid crystallization process of perovskite produces a large number of defects that remain a critical factor that disturbs the performance of perovskite solar cells (PSCs). In this research, these challenges are mitigated by introducing multifunctional 2,6-pyridinedicarboxylic acid chloride (PAC) as an additive into perovskite. During the thermal annealing process, the predominant accumulation of PAC occurs at the upper and buried interfaces of perovskite film. PAC possesses multiple passivating sites that facilitate the anchoring of lead and iodine defects, thereby enhancing the quality of the perovskite material across both its dual interfaces and grain boundaries. With this unique property, combined with the advantages of enhanced crystallization, reduced non-radiative recombination, boosted charge carrier mobility, and optimal energy level alignment, the PSC achieved a power conversion efficiency (PCE) of 25.60% and maintained more than 90% efficiency after 3000 h under one solar equivalent light and more than 90% efficiency after 1400 h under dark and high temperature (85 °C). The dual interface passivation strategy provides a sustainable solution to both stability and environmental challenges for the commercialization of perovskite solar cells.