Ultralong Carrier Lifetime Exceeding 20 µs in Lead Halide Perovskite Film Enable Efficient Solar Cells

The carrier lifetime is one of the key parameters for perovskite solar cells (PSCs). However, it is 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 the developed 2-thiopheneformamidinium bromide (ThFABr) combined with the unique film structure of 2D perovskite layer caped 2D/3D polycrystalline perovskite film, an ultralong carrier lifetime exceeding 20 µs and carrier diffusion lengths longer than 6.5 µm are achieved. These excellent properties enable the ThFA-based devices to yield a champion efficiency of 24.69% with a minimum V