Interfacial Passivation and Energy Level Alignment Regulation for Self‐Powered Perovskite Photodetectors with Enhanced Performance and Stability

Abstract Interfacial passivation and energy level alignment regulation at perovskite and charge transport layer interface are urgently desirable for constructing efficient and stable self‐powered perovskite photodetectors. Herein, a modified additive‐containing antisolvent strategy that not only facilitates high quality perovskite film formation but also modulates energy level alignment at interface is developed to improve the photoresponse and stability of perovskite photodetectors. Specifically, poly(3‐hexylthiophene) (P3HT) is introduced as functional additive into the antisolvent chlorobenzene. P3HT molecules penetrate along perovskite grain boundaries to fill the pinholes and passivate Pb 2+ defects. Furthermore, the valence band maximum of the surface of the perovskite layer is modulated to form a favorable band energy alignment with the hole transport layer (HTL). The suppressed carrier recombination at the perovskite/HTL interface results in reduced noise current and improved photocurrent. Finally, the optimized device achieves a responsivity of 0.41 A W ‐1 , a detectivity of 0.61 × 10 12 Jones at 700 nm, and a linear dynamic response range of 118 dB without external bias. In addition, the unpackaged device still maintains 78% of initial performance after 720 h under ambient conditions, indicating its superior stability compared with the original device.