Additive engineering of novel double-site passivator in perovskite solar cells

Through additive engineering, perovskite solar cells form bulk heterojunctions (BHJ), which have advantages in passivating defects and promoting electron extraction and transport. Most of the fullerene derivatives of BHJ-PVKSCs exhibit single-point interactions that limit their passivation. In this work, two kinds of carbonyl co-functionalized with fullerene derivatives (3F–C60,7F–C60) with different fluorine chain lengths are designed and synthesized, interact with perovskite through additive engineering, and can obtain champion efficiencies of 19.54% and 20.34%. The reasons for the different effects of different fluorocarbon chain lengths on device performance are discussed. The passivation ability is partly derived from the interaction between CO based on Pb2+, and partly from the hydrogen bond between halothane based on CH3NH3+ cations. This approach makes the orientation of CH3NH3+ orderly and inhibits ion migration, thereby improving the efficiency and stability of the humid environment.