Metal–Organic Framework‐Derived N‐Rich Porous Carbon as an Auxiliary Additive of Hole Transport Layers for Highly Efficient and Long‐Term Stable Perovskite Solar Cells

As the standard bidopants of hole transport layers (HTLs) in perovskite solar cells (PSCs), bis(trifluoromethane)sulfonimide lithium salt (Li‐TFSI) and 4‐ tert ‐butylpyridine not only induce adverse influence on the quality of thin films, but also seriously impair the long‐term stability of devices. Herein, a metal–organic framework‐derived 2D graphitic N‐rich porous carbon (NPC) is first introduced into the HTLs as an effective auxiliary additive. The introduction of NPC significantly reduces the aggregation of lithium salts and the formation of HTL defects, optimizing film quality for rapid hole extraction and migration. Furthermore, inherent porosity and hydrophobicity of NPCs are extremely beneficial to restrict the permeation of Li + ions and anode metals, and prevent the moisture from eroding the HTLs and perovskite layers, enhancing the stability of PSCs. As expected, the PSCs with NPC realize a satisfactory fill factor of 0.76 and power conversion efficiency (PCE) of 18.51%, apparently higher than that of pristine devices (0.70% and 16.47%). In addition, over 85% of the initial PCE for optimized PSCs is maintained after 720 h of exposure to air. Obviously, an innovative strategy for highly efficient and long‐term stable PSC devices is provided.