Architecturing 1D‐2D‐3D Multidimensional Coupled CsPbI₂Br Perovskites toward Highly Effective and Stable Solar Cells

Abstract Despite the rapid development of CsPbI_xBr_3−x (0 ≤ x ≤ 3) inorganic perovskite solar cells, associated with their superior thermal stability, their low moisture stability limits their commercial deployment. In this study, 1D‐2D‐3D multidimensional coupled perovskites are prepared by means of an in situ self‐integration approach. This pioneering method allows incorporating thus far unreported 1D‐Tpy₂Pb₃I₆ and 2D‐TpyPb₃I₆ (Tpy; terpyridine) perovskites. Heterojunction perovskites demonstrate superior stability against water in comparison with control 3D CsPbI₂Br, which is related to the hydrophobicity of low‐dimension (LD) perovskites. Remarkably, the spontaneous involvement of LD perovskites can adjust/reconstruct the interfacial structure. This modification allows releasing the residual strain, establishing effective charge transfer channels that increase the carrier transport ability. Accordingly, 1D‐2D‐3D hybrid CsPbI₂Br perovskite solar cells demonstrate a stabilized power conversion efficiency as high as 16.1%, which represents a very significant improvement, by a factor of 43%, with respect to control 3D CsPbI₂Br perovskite solar cell. Equally importantly, the multidimensional coupled perovskite solar cells exhibit extraordinary stability, well above 1000 h in ambient atmosphere.