Triple Passivation Approach to Laminate Perovskite Layers for Augmented UV and Ambient Stable Photovoltaics

The instability of the perovskite solar cells (PSCs) toward ultraviolet (UV) irradiation and moisture is a limiting factor in terms of commercialization even after achieving excellent power conversion efficiencies (PCEs). Herein, an advanced triple passivation technique has been strategically designed and demonstrated utilizing UV-absorbing 2-benzoylpyridine (BP) molecules as a passivation additive to laminate perovskites and improve PSC stability. Double layers of BP were coated on both sides of the perovskite layer, and the molecule was also incorporated into the precursor solution. This strategy significantly improved the perovskite crystallinity and film quality, lowered the recombination, and enhanced the carrier transport in the PSC. The triple-passivated device exhibited a high PCE of 20.46% with almost negligible hysteresis. Further, passivated large-area (2.5 cm2) devices were also fabricated that demonstrated a PCE of 18.61%. Moreover, the triple passivation approach exhibited impressive UV and ambient stability because it can effectively shield the perovskite layer from UV illumination and moisture.