All-in-One Lewis Base for Enhanced Precursor and Device Stability in Highly Efficient Perovskite Solar Cells

With skyrocketing interest and achievement of tremendous research efforts, perovskite solar cells are on the verge of commercialization. However, the stabilities of precursors and devices provide challenges for commercialization. Many researchers have dealt with these issues separately. Here, we introduce novel diphthalic anhydride-based Lewis base additives that address the precursor and device stability difficulties simultaneously. The added Lewis bases showed excellent interactions with Pb²⁺ and FA⁺ cations in the precursor and perovskite crystal. Accordingly, the facile Lewis-base-added perovskite precursor exhibited 85% ambient storage stability, and the device retained 90% of its initial efficiency after 1,000 h of heating at 80 °C (thermal) or 50% relative humidity atmospheric testing without encapsulation. Furthermore, the interaction between the facile Lewis base and various cations suppressed the related grain boundary defects, thus improving the efficiency from 19.58% of the control device to 22.43% of the target device.