The Key Role of Hole Transport Layer in Boosting Performance of Two‐Dimensional Perovskite Solar Cells

Although currently in the nascent stages of research and development, two‐dimensional perovskite solar cells have showcased remarkable promise as the robust and efficient solar cell technology. Anticipated progressions and refinements in this domain are poised to establish two‐dimensional perovskite cells as instrumental catalysts in shaping the trajectory of renewable energy, heralding transformative breakthroughs. The hole transport layer (HTL) plays an irreplaceable role in the charge carriers’ transport and interface effects in two‐dimensional perovskite devices. This review starts with the structural characteristics of two‐dimensional perovskite solar cells. The influence of the intrinsic characteristics of the perovskite active layer itself and the interaction of the perovskite/transport layer contact interface are analyzed. This discussion delves into the impact of intrinsic quantum confinement and the dielectric effect within the two‐dimensional perovskite structure on photovoltaic conversion efficiency. It also explores the energy level alignment between the clathrate active layer and the transport layer. The significance of the HTL is emphasized, particularly regarding crystalline control, phase distribution, and interface passivation. Additionally, the crucial role of efficient carrier transport between the active layer and the transport layer is thoroughly examined.