While the primary focus for many additives in perovskite solar cells (PSCs) is enhancing power conversion efficiency (PCE), the long-term viability of this technology hinges on its stability and durability. 1,4-Phenylenediamine Dihydriodide (PDAI) stands out as an additive that not only boosts PCE but also addresses these critical stability concerns, offering a more comprehensive solution for advanced photovoltaic applications.

PDAI’s influence on stability is multifaceted. By acting as an interface modifier, it promotes the formation of a 2D perovskite layer at the junction of the perovskite absorber and the hole transport layer. This engineered interface provides a protective barrier, reducing the ingress of moisture, which is a primary cause of perovskite degradation. The resulting perovskite films exhibit enhanced resistance to humidity-induced decomposition, maintaining higher performance over extended periods.

Furthermore, PDAI has demonstrated a remarkable ability to imbue PSCs with self-healing properties. When exposed to environmental stressors like humidity, the perovskite material can undergo a certain degree of degradation. However, in PDAI-treated cells, this degradation is often reversible. Upon removal from the moisture source, the perovskite structure can partially recover its original crystalline phase and functionality, thanks to the stabilizing influence of PDAI molecules within the grain boundaries. This self-healing capability is a significant advancement in making PSCs more robust and forgiving to environmental fluctuations.

The self-healing mechanism is intricately linked to PDAI's chemical structure. The diammonium cation and aromatic ring contribute to a more cohesive and resilient perovskite lattice. These features help to prevent the irreversible migration of ions and the formation of volatile decomposition products that are typical in untreated perovskite films. Consequently, PDAI-modified films are less prone to permanent damage and can effectively mend themselves, extending the operational lifespan of the solar cells.

The dual benefits of increased efficiency and enhanced stability and self-healing capabilities position PDAI as a highly versatile and valuable additive for the advancement of perovskite solar cell technology. Its contributions go beyond mere performance enhancement, addressing fundamental challenges that have limited the commercialization of PSCs. As research continues to refine the application and understanding of PDAI, it is poised to play an instrumental role in developing the next generation of reliable and high-performing solar energy devices.