Hetero-perovskite engineering for stable and efficient perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have become promising next generation photovoltaic materials due to their excellent power conversion efficiency (PCE) based on the high carrier mobility, large absorption scope, long carrier diffusion and unique structural tunability of the active perovskite layers. At present, it is a priority for PSCs to further improve the PCE and long-term stability. Metal halide perovskites can be regulated to multiple structures and dimensions by rational design of components, such as three-dimensional (3D) and low-dimensional (0-2D) perovskites at the molecular level, which show totally different optoelectronic properties. Combining the low-dimensional perovskites with 3D ones, more stable 2D/3D, 1D/3D, and 0D/3D perovskite heterostructures can be formed. Compared with single component perovskites, hetero-perovskites (HPs) provide a promising chance to obtain efficient PSCs with long-term stability. Herein, the latest application progress and optimization mechanism for HPs are summarized and discussed to provide systematic knowledge and prospects of their development in the photovoltaic field.