Lattice-matched in-situ-formed 1D perovskite phase in Multi-dimensional solar cells achieving high phase stability and favorable energy landscape

Despite possessing superior stability, multi-dimensional perovskites face challenges with charge transport at device interfaces due to large size organic cations. The molecular size and shape of these cations influence the crystal structure of low-dimensional perovskite phases. In this study, we introduce a straightforward approach for fabricating surface-modified multi-dimensional (1D/3D) perovskite structures using pyridinium treatment. Our results demonstrate that pyridinium-based low-dimensional perovskite crystals exhibit lattice-matching crystal structures with the underlying 3D perovskite layer. This leads to thermodynamically stable configurations and cascade energy band alignment. Importantly, the relatively small size of pyridinium ensures efficient charge transport toward charge collection electrodes. Devices treated with pyridinium exhibit a significant increase in power conversion efficiency, from 22.97% to 23.74%. Moreover, the 1D/3D hybrid structure enhances both hydrophobicity and device stability, maintaining 80% of the initial power conversion efficiency under conditions of 85% relative humidity, even without encapsulation. This study lays the groundwork for the development of novel organic halide salts in 1D/3D perovskite architectures and offers an efficient surface passivation strategy for high-performance and stable perovskite solar cells.