LAUSR

The carrier lifetime is one of the key parameters for perovskite solar cells. However, it's still a great challenge to achieve long carrier lifetimes in perovskite films that are comparable with perovskite crystals owning to the large trap density resulting from the unavoidable defects in grain boundaries and surfaces. Here, by regulating the electronic structure with ou r developed 2-thiopheneformamidinium bromide (ThFABr) combined with the unique film structure of 2D perovskite layer caped 2D/3D polycrystalline perovskite film, w e achieved an ultra-long carrier lifetime exceeding 20 μs and carrier diffusion lengths longer than 6.5 μm. These excellent properties enable the ThFA-based devices to yield a champion efficiency of 24.69% with a minimum VOC loss of 0.33 V. The unencapsulated device retained ∼95% of its initial efficiency after 1180 h by max power point (MPP) tracking under continuous light illumination. Our work provides important implications for structured 2D/(2D/3D) perovskite films combined with unique FA-based spacers to achieve ultralong carrier lifetime for high-performance PSCs and other optoelectronic applecations. This article is protected by copyright. All rights reserved.