An Orientation-Enhanced Interlayer Enables Efficient Sn–Pb Binary Perovskite Solar Cells and All-Perovskite Tandem Solar Cells with High Fill Factors

The performance of narrow-bandgap (NBG) perovskite solar cells (PSCs) is limited by the severe nonradiative recombination and carrier transport barrier at the electron selective interface. Here, we reveal the importance of the molecular orientation for effective defect passivation and protection for Sn