Ion‐Diffusion Management Enables All‐Interface Defect Passivation of Perovskite Solar Cells

determines the composition of the bulk and buried interface of PSCs. As a result, n-inter-i-inter-p, i.e., five-layer structured PSCs can be obtained with a champion PCE of 25.43% (certified 24.4%). This approach also enables the substantially improved operational stability of perovskite solar cells.