Device Physics and Design Principles of Mixed‐Dimensional Heterojunction Perovskite Solar Cells

Abstract

Mixed‐dimensional perovskites possess unique photoelectric properties and are widely used in perovskite solar cells (PSCs) to improve their efficiency and stability. However, there is a pressing need for a deeper understanding of the physical mechanisms and design principles of mixed‐dimensional PSCs, as such knowledge gaps impose restrictions on unlocking the full potential of this kind of PSC. Herein, a 2D/3D PSC is employed as an example to clarify the working mechanism of mixed‐dimensional PSCs from the perspective of device physics and elaborate on the design rules of high‐efficiency mixed‐dimensional PSCs. Detailed simulation results indicate that the insertion of a layer of 2D perovskite between the 3D perovskite and the hole transport layer (HTL) can significantly reduce the recombination at the HTL/perovskite interface, and PSCs with a 2D/3D perovskite structure exhibit higher tolerance to material selectivity compared with their 3D counterparts. Additionally, the 2D/3D perovskite design can slow down ion migration and accumulation processes, thereby easing the hysteresis behavior of 2D/3D PSCs. Moreover, it is also found that the 2D/3D perovskite structure has a more pronounced effect on improving the efficiency of wide‐bandgap PSCs. Overall, this work sheds new light on mixed‐dimensional PSCs, enabling better guidance for designing high‐efficiency PSCs.