AI-Generated Ammonium Ligands for High-Efficiency and Stable 2D/3D Heterojunction Perovskite Solar Cells.

The 2D/3D heterojunction perovskite solar cells (PSCs) exhibit remarkable stability, but the quantum well in the 2D perovskite capping layer hinders the carrier transport, thereby lowering the power conversion efficiency (PCE). The relationship between the transport barrier and the complex structure of ammonium ligands (ALs) is currently poorly understood, thus leading to the one-sided approach and inefficient process in the development of 2D perovskite. Here, a machine learning procedure is established to comprehensively explore the relationship and combined it with an artificial intelligence (AI) model based on reinforcement learning algorithm to accelerate the generation of ALs. Finally, the AI-designed ALs improved the carrier transport performance of the 2D perovskite capping layer, and we achieved a certified PCE of 26.12% in inverted PSCs. The devices retained 96.79% of the initial PCE after 2000 h operation in maximum power point tracking under 1-sun illumination at 85°C.