CsPbIxBry-based all-inorganic perovskite materials are a potential candidate for stable semitransparent and tandem structured photovoltaic devices. However, poor film (morphological and crystalline) quality and interfacial recombination lead consequently to a decline in the photoelectric conversion performance of the applied solar cells. In this work, we incorporated PbS quantum dots (QDs) at the interface of electron transporting layer (ETL) SnO 2 and perovskite to modulate the crystallization of CsPbIBr 2 and the interfacial charge dynamics in carbon-based solar cells. The ascasted PbS QDs behave as seeds for lattice-matching the epitaxial growth of pinhole-free CsPbIBr 2 films. The modified films with reduced defect density exhibit facilitated carrier transfer and suppressed charge recombination at the ETL/perovskite interface, contributing to an enhanced device efficiency from 7.00 to 9.09% and increased reproducibility and ambient stability. This strategic method of QD-assisted lattice-matched epitaxial growth is promising to prepare high-quality perovskite films for efficient perovskite solar cells.

Perovskite solar cells (PSCs) via two-step sequential method have received great attention in recent years due to their high reproducibility and low processing costs. However, the relatively high trap-state density and poor charge carrier extraction efficiency pose challenges. Herein, highly efficient and stable PSCs via a two-step sequential method are fabricated using organic-inorganic (OI) complexes as multifunctional interlayers. In addition to reduce the under-coordinated Pb 2+ ions related trap states by forming interactions with the functional groups, the complexes interlayer tends to form dipole moment which can enhance the built-in electric field, thus facilitating charge carrier extraction. Consequently, with rational molecular design, the resulting devices with a vertical dipole moment that parallels with the built-in electric field yield a champion efficiency of 23.55% with negligible hysteresis. More importantly, the hydrophobicity of the (OI) complexes contributes to an excellent ambient stability of the resulting device with 91% of initial efficiency maintained after 3000 h storage.

Perovskite solar cells (PSCs) have witnessed rapid development toward commercialization based on their superior efficiency except for some remained misgivings about their poor stability primarily originating from interfacial problems. Robust back interface for neutralization of crystal defects, depression of dopant lithium ions (Li+) diffusion, and even inhibition of toxic lead (Pb) leakage is highly desirable; however, it remains a great challenge. Herein, a cost‐effective interfacial therapy approach is developed to simultaneously alleviate the obstacles aforementioned. A small molecule, 1,4‐dithiane with unique chair structure, is adapted to interact with under‐coordinated Pb2+ on perovskite surface and Li+ from hole transport layer, neutralizing interfacial defects and suppressing Li+ diffusion. Besides, the presence of 1,4‐dithiane can efficiently modulate interfacial energetics, enhance hydrophobicity of PSCs, and anchor Pb atoms via SPb bond. Consequently, the target devices perform better than control devices when exposed to light‐soaking, moisture, and thermal stress owing to the synergistic suppression of trap‐state density, ions migration, and moisture permeation. The optimized target device delivers a champion efficiency of 23.27% with mitigated Pb leakage. This study demonstrates a promising functionalized modification strategy for constructing efficient, stable, and eco‐friendly PSCs.