Thienyltriazine Triamides: Thickness Insensitive Interlayer Materials Featuring Fine‐Tuned Optoelectronic and Aggregation Characters for Efficient Organic Solar Cells

A novel class of thienyltriazine triamides (TTTAs) was facile synthesized and firstly used as cathode interlayers (CILs) for organic solar cells (OSCs). By utilizing different aromatic arms and pendant polar groups, their optoelectronic properties and aggregation behaviors were effectively modulated. The combination of thienyltriazine (TT) core, naphthylamide arm and imidazole pendant group endows TT-N-M with suitable energy levels, intensified work function tunability, higher conductivity, and well-balanced crystallinity and film-forming ability, boosting both the performance and stability of OSCs significantly. Remarkably, the solar cell efficiency remains stable at around 90 % of the optimal efficiency even as the interlayer thickness varied from 5 to 95 nm, demonstrating its insensitivity to thickness. Moreover, TT-N-M exhibits compatibility with various active layer systems, achieving a maximum efficiency of 19.60 % for single-junction solar cell. Its exceptional tolerance to thickness fluctuations and performance establishes a new benchmark for multi-armed CIL-based OSCs, also positioning them among the most high-performing CIL materials documented thus far. This work not only broadens the scope of CIL materials for OSCs but also offers deep insights into design strategies and structure-properties relationships, being beneficial for the future development of more efficient CIL materials for organic optoelectronic applications.