In organic solar cells (OSCs), cathode interfacial materials are generally designed with highly polar groups to increase the capability of lowering the work function of cathode. However, the strong polar group could result in a high surface energy and poor physical contact at the active layer surface, posing a challenge for interlayer engineering to address the trade-off between device stability and efficiency. Herein, we report a hydrogen-bonding interfacial material, aliphatic amine-functionalized perylene-diimide (PDINN), which simultaneously down-shifts the work function of the air stable cathodes (silver and copper), and maintains good interfacial contact with the active layer. The OSCs based on PDINN engineered silvercathode demonstrate a high power conversion efficiency of 17.23% (certified value 16.77% by NREL) and high stability. Our results indicate that PDINN is an effective cathode interfacial material and interlayer engineering via suitable intermolecular interactions is a feasible approach to improve device performance of OSCs.

Organic solar cells (OSCs) have experienced rapid progress with the innovation of near‐infrared (NIR)‐absorbing small‐molecular acceptors (SMAs), while the unique electronic properties of the SMAs raise new challenges in relation to cathode engineering for effective electron collection. To address this issue, two fluorinated perylene‐diimides (PDIs), PDINN‐F and PDINN‐2F, are synthesized by a simple fluorination method, for application as cathode interlayer (CIL) materials. The two bay‐fluorinated PDI‐based CILs possess a lower lowest unoccupied molecular orbital (LUMO) energy level of ≈−4.0 eV, which improves the energy level alignment at the NIR‐SMAs (such as BTP‐eC9)/CIL for a favorable electron extraction efficiency. The monofluorinated PDINN‐F shows higher electron mobility and better improved interfacial compatibility. The PDINN‐F‐based OSCs with PM6:BTP‐eC9 as active layer exhibit an enhanced fill factor and larger short‐circuit current density, leading to a high power conversion efficiency (PCE) exceeding 18%. The devices with PDINN‐F CIL retain more than 80% of their initial PCE after operating at the maximum power point under continuous illumination for 750 h. This work prescribes a facile, cost‐effective, and scalable method for the preparation of stable, high‐performance fluorinated CILs, and instilling promise for the NIR‐SMAs‐based OSCs moving forward.

A novel cyanine dye supramolecular assembly was designed to recognize mixed G-quadruplex in human telomeres.