The elaborate control of the vertical phase distribution within an active layer is critical to ensuring the high performance of organic solar cells (OSCs), but is challenging. Herein, a self‐stratification active layer is realised by adding a novel polyfluoroalkyl‐containing non‐fullerene small‐molecule acceptor (NFSMA), EH‐C8F17, as the guest into PM6:BTP‐eC9 blend. A favourable vertical morphology was obtained with an upper acceptor‐enriched thin layer and a lower undisturbed bulk heterojunction layer. Consequently, a power conversion efficiency of 18.03 % was achieved, higher than the efficiency of 17.40 % for the device without EH‐C8F17. Additionally, benefiting from the improved charge transport and collection realised by this self‐stratification strategy, the OSC with a thickness of 350 nm had an impressive PCE of 16.89 %. The results of the study indicate that polyfluoroalkyl‐containing NFSMA‐assisted self‐stratification within the active layer is effective for realising an ideal morphology for high‐performance OSCs.

Near‐infrared (NIR) organic photodetectors (OPDs) are competitive candidates for flexible electronics in biomedical imaging and optical communications applications. However, current OPDs still suffer from a low detectivity beyond 1000 nm and a high dark current at bias due to the lack of high‐performance narrow‐bandgap non‐fullerene acceptors (NFAs). In this study, spiro‐conjugated core donor (D) unit is adopted to construct NFAs, SPT‐4F and tSPT‐4F. Comparing with PT‐4F without spiro‐conjugation, the orthogonal spiro‐conjugated planes endow SPT‐4F and tSPT‐4F with more rigid conformation and thus superior intermolecular stacking, resulting in the enhanced absorption beyond 1000 nm. Impressively, tSPT‐4F based device gives the best performance with a dark current of 4.52 × 10−10 A cm−2 under reversed bias of −0.1 V, an external quantum efficiency (EQE) response over 48% at 1010 nm, a detectivity of 1.25 × 1013 Jones and a responsibility of 0.40 A W−1 at 1010 nm. To the best of the authors' knowledge, this is one of the best performed devices reported to date for binary NIR OPDs with response beyond 1000 nm. This study provides a feasible molecular design strategy to develop narrow‐bandgap NFAs with spiro‐conjugation for highly detective NIR OPDs.

No abstract

No abstract

1,4-Azaborine, containing both boron and nitrogen in an aromatic hydrocarbon, displays unique electronic properties compared with its all-carbon analogue and shows great potential as multiresonant thermally activated delayed fluorescence materials....