Roles of Organic Molecules in Inorganic CsPbX 3 Perovskite Solar Cells

Over 25% efficiencies have been achieved by organic–inorganic hybrid perovskite solar cells (PSCs). However, their practical applications are limited by the instability of the hybrid perovskite materials. Replacing hybrid perovskites with inorganic CsPbX 3 perovskites shows great promise to address the above issue and much progress has been made. To achieve high efficiency and stable inorganic CsPbX 3 PSCs, organic molecular engineering has been playing a vital role. Herein, the progress of the organic molecular engineering in inorganic CsPbX 3 PSCs is systematically reviewed. First, structure evolution induced by organic molecular engineering for inorganic CsPbX 3 perovskites is demonstrated. Then, organic molecular engineering in CsPbX 3 PSCs is categorized and reviewed (alloying in perovskite structures, as sacrificial agents, forming 2D structures, and modifying surfaces and interfaces). Finally, future research directions are suggested to further improve the performance of inorganic PSCs.