A Refined Bulk P–I–N Structure in All-Polymer Solar Cells To Achieve 20.1% Efficiency and Improved Stability

All-polymer solar cells (all-PSCs) have shown good potential for achieving balanced power conversion efficiency (PCE) and operational stability. However, precise control of the morphology remains challenging. Here, we constructed a bulk p–i–n structure with a regulated i-region by incorporating a shamrock-shaped nonfullerene acceptor, AQI4. This ternary formulation resulted in optimized energy-level stairing, enhanced exciton dissociation, and reduced energy loss. In blended thin film fabrication, a binary solvent of chlorobenzene (CB):o-xylene (OXY) was used, which enhanced the crystallization of the polymers and formed a high-density fibril network. The i-region width was reduced to less than 2 nm. This…

• NN
  National Natural Science Foundation of China

  Awards: 22379094, 52373176, 22309111, 22171273, 52325306
• SA
  Science and Technology Commission of Shanghai Municipality

  Award: 21DZ1208602