Molecular Self‐Assembly Regulated Dopant‐Free Hole Transport Materials for Efficient and Stable n‐i‐p Perovskite Solar Cells and Scalable Modules

Dopant‐free organic hole transport materials (HTMs) remain highly desirable for stable and efficient n‐i‐p perovskite solar cells (pero‐SCs) but rarely succeed. Here, we propose a molecular assembly strategy to overcome the limited optoelectronic properties of organic HTMs by precisely designing a linear organic small molecule BDT‐DPA‐F from the atomic to the molecular levels. BDT‐DPA‐F can assemble into a fibril network, showing an obviously improved hole mobility and decreased energy disorder. The resultant pero‐SCs showed a promising efficiency of 23.12 % (certified 22.48 %), which is the highest certified value of pero‐SCs with dopant‐free HTMs, to date. These devices also showed a weak‐dependence of efficiency on size, enabling a state‐of‐the‐art efficiency of 22.50 % for 1‐cm2 device and 20.17 % for 15.64‐cm2 module. For the first time, the pero‐SCs based on dopant‐free HTMs realized ultralong stabilities with T80 lifetimes over 1200 h under operation or thermal aging at 85 °C. A hole transport material (BDT‐DPA‐F) is designed, and it can assemble into a fibril network, showing an obviously improved hole mobility, a decreased energy disorder and high scalability. The perovskite solar cells based on BDT‐DPA‐F without any dopant obtain promising power conversion efficiencies of 23.12 % (certified 22.48 %) for small‐area devices (0.062 cm2) and 20.17 % for large‐area modules (15.64 cm2).