Toughened Hybrid Electron-Transporting Interlayers for Efficient and Durable Organic Solar Cells

Electron-transporting layers (ETLs) are crucial in determining the performance of organic solar cells (OSCs). However, it is challenging to achieve desired efficiency and stability simultaneously for devices based on single-component ETLs. Here, we demonstrate the application of polyoxometalate (POM)-doped hybrid ETLs to achieve significantly mitigated efficiency-stability trade-off in OSCs. By tailoring the doping behaviors, hybrid ETLs exhibit cascade energy-level alignment, increased conductivity, improved electrode adhesion, strong thickness tolerance, and suppressed self-aggregation. These combined merits enable excellent efficiency (20.4%) and outstanding stability (a T₉₃/T₉₂ lifetime of 1500/1000 h under MPP tracking at 40°C/65°C) to be achieved for OSCs. A further elevated efficiency of 20.8% (20.4%, certified) and a T₉₀ lifetime of 1000 h can also be achieved when PDIN-EME is used as the new organic component in the hybrid ETL, demonstrating the easy tunability of these hybrid interlayers for more efficient and robust OSCs.