Efficient and Stable Inverted MA/Br-Free 2D/3D Perovskite Solar Cells Enabled by α-to-δ Phase Transition Inhibition and Crystallization Modulation

The α-to-δ phase transition and lattice defects pose significant challenges to the long-term stability of methylammonium (MA)/bromide (Br)-free formamidinium (FA)-based perovskite solar cells (PSCs). Here we propose an approach for...