Synthesis of Naphthalimide Polymer Acceptors and Application in Thick Film Polymer Solar Cells

The development of thickness‐insensitive polymer solar cells (PSCs) is critical for large‐scale commercialization. However, high‐performance PSCs typically require active layers of only 100 nm, and their efficiency drops significantly with increasing thickness. Herein, we synthesized a novel conjugated polymer acceptor, PBDT‐N, and introduced it into PM6:Y6 to fabricate efficient ternary PSCs. PBDT‐N effectively enhances electron mobility and balances charge transport in the devices. Additionally, the introduction of the third component optimizes the morphology of the device's active layer. Compared to binary devices, the ternary devices exhibit higher exciton dissociation and charge collection efficiency, while also effectively suppressing carrier recombination. As a result, the PM6: PBDT‐N: Y6 device with a film thickness of 120 nm achieves a power conversion efficiency (PCE) of 17.31%, when the active layer thickness is increased to 300 nm, the PCE reached 15.86%, with an open‐circuit voltage ( V OC ) of 0.847 V, a short‐circuit current density ( J SC ) of 25.43 mA/cm 2 , and a fill factor of 73.65%. This work provides an effective strategy for fabricating high‐performance thick‐film devices, laying a solid foundation for the roll‐to‐roll large‐area and large‐scale production of PSCs in the future.