Molecular Synergistic Passivation for Efficient Perovskite Solar Cells and Self-Powered Photodetectors

The interface between the perovskite and electron-transporting material is often treated for defect passivation to improve the photovoltaic performance of devices. A facile 4-Acetamidobenzoic acid (containing an acetamido, a carboxyl, and a benzene ring)-based molecular synergistic passivation (MSP) strategy is developed here to engineer the SnO_x /perovskite interface, in which dense SnO_x are prepared using an E-beam evaporation technology while the perovskite is deposited with vacuum flash evaporation deposition method. MSP engineering can synergistically passivate defects at the SnO_x /perovskite interface by coordinating with Sn⁴⁺ and Pb²⁺ with functional group CO in the acetamido and carboxyl. The optimized solar cell devices can achieve the highest efficiency of 22.51% based on E-Beam deposited SnO_x and 23.29% based on solution-processed SnO₂ , respectively, accompanied by excellent stability exceeding 3000 h. Further, the self-powered photodetectors exhibit a remarkably low dark current of 5.22 × 10^-9  A cm^-2 , a response of 0.53 A W^-1 at zero bias, a detection limit of 1.3 × 10¹³  Jones, and a linear dynamic range up to 80.4 dB. This work proposes a molecular synergistic passivation strategy to enhance the efficiency and responsivity of solar cells and self-powered photodetectors.