Quantum Dot Interface-Mediated CsPbIBr₂ Film Growth and Passivation for Efficient Carbon-Based Solar Cells

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) SnO₂ and perovskite to modulate the crystallization of CsPbIBr₂ and the interfacial charge dynamics in carbon-based solar cells. The as-casted PbS QDs behave as seeds for lattice-matching the epitaxial growth of pinhole-free CsPbIBr₂ 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.