Dimensional Engineering in Efficient and Stable Inverted Perovskite Solar Cells

Perovskite solar cells (PSCs) have attracted much attention in the field of photovoltaics, due to their high power conversion efficiency (PCE) and low cost. In recent years, inverted PSCs have achieved significant advancements in PCE and operational stability. Among the strategies for optimizing PCE and lifespan of inverted PSCs, dimensional engineering plays a critical role and garners increasing attention due to its versatile functions of passivating defects, releasing residual tensile stress, strengthening structural stability, ameliorating carrier transport and extraction, and so on. Considering the importance of dimensional engineering, a comprehensive and deep understanding of 2D perovskites and 2D/3D heterojunction is definitely necessary. In this review, first, the progress of low-dimensional perovskite light-harvesting materials in inverted PSCs is summarized. Subsequently, the advances in constructing 2D/3D perovskite heterojunctions, including 2D/3D bulk heterojunction within perovskite materials, 2D/3D interfacial heterojunction at the interface between perovskite film and carrier transport layer, and bottom-up 2D/3D perovskite heterojunction are discussed. The simultaneous construction of 2D/3D heterojunction at dual interfaces is highlighted. Finally, the legitimate outlook on the further development of dimensional engineering is proposed to advance the commercialization of inverted photovoltaic technology.