Interfacial dipole engineering in all-inorganic perovskite solar cells

Severe nonradiative recombination and energy level mismatch in perovskite solar cells (PSCs) are key factors affecting efficiency. Here, we report an effective strategy for surface passivation and interfacial dipole engineering of perovskite films. By precisely introducing electron-withdrawing and electron-donating groups on 7-azaindole, we have effectively controlled the passivation ability of N atoms and the polarity of the interfacial dipole, thereby regulating the perovskite surface's work function and obtaining the optimal energy level matching. This strategy yields an impressive efficiency of 10.76% for the CsPbBr3 PSC and exceptional stability. Different functional groups on 7-azaindole (7-AI) alter its passivation ability and dipole moment. Finally, 7-AI-OCH3 proves to be highly effective in passivating defects and optimizing energy level alignment.