Simple fused-ring nonfullerene acceptor BDDEH with benzobithiophenedione as core unit is obtained through organostannane-free and ligand-free direct heteroarylation approach for the first time, which delivers a high efficiency of 12.59% in PSCs.

Near‐infrared organic photodetector of high sensitivity is essential for various remote sensing applications. In this work, a new simple fused‐ring acceptor “NTQ” with a narrow optical bandgap of 1.11 eV is designed and synthesized to demonstrate the first near‐infrared organic photodetector example featuring a non‐fused A‐D‐A′‐D‐A molecular framework. The optimized geometry of NTQ exhibits high planarity and the relevant pristine film shows high electron mobility of 1.51 × 10−4 cm2 V−1 s−1. Moreover, the PTB7‐Th:NTQ blend can achieve relatively high and balanced hole/electron mobility even though the photo‐active layer thickness is up to 320 nm. The NTQ‐based devices exhibit high shot‐noise‐limited specific detectivity (Dsh*) of 3.72 × 1012 Jones at 1000 nm under the bias of –0.1 V and a board Dsh* response over 1012 Jones from 320 to 1070 nm. Furthermore, the device exhibits fast averaged rise and fall times of 2.02 and 2.42 µs, respectively. This work demonstrates that molecular engineering with the A‐D‐A′‐D‐A framework can endow near‐infrared photo‐active materials with high‐performing photodetectors for wide applications.

Molecular orientation in polymer solar cells (PSCs) is a critical subject of investigation that promotes the quality of bulk heterojunction morphology and power conversion efficiency (PCE). Herein, the intrinsic polymer orientation transition can be found upon delicate control over the branching point position of the irregular alkoxy side chain in difluoroquinoxaline−thiophene-based conjugated polymers. Three polymers with branching points at the third, fourth, and fifth positions away from the backbone were synthesized and abbreviated as PHT3, PHT4, and PHT5, respectively. Temperature-dependent absorption behavior manifests the polymer aggregation ability in the order of PHT3 < PHT4 < PHT5. Surprisingly, the polymer orientation transition from typical face-on to edgeon emerged between PHT4 and PHT5, as evidenced by X-ray-scattering analysis. The enhanced face-on crystallinity of PHT4 endowed the o-xyleneprocessed PHT4:IT-4Cl-based devices with the highest PCE of 13.40%. For PHT5 with stronger aggregation, the related o-xylene-processed PSCs still showed a good PCE of 12.66%. Our results demonstrate that a delicate polymer orientation transition could be realized through a precisely controlled strategy of the side chain, yielding green-solvent-processed high-performance PSCs.

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Short‐wavelength infrared (SWIR) organic light‐emitting diodes (OLEDs) have attracted great interest due to their potential applications in biological imaging, infrared lighting, optical communication, environmental monitoring, and surveillance. Due to an intrinsic limitation posed by the energy‐gap law, achieving high‐brightness in SWIR OLEDs remains a challenge. Herein, the study reports the use of novel A–D–A′–D–A type small molecules NTQ and BTQ for high‐performance SWIR OLEDs. Benefiting from multiple D–A effect in conjugated skeleton, the small molecules NTQ and BTQ exhibit narrow optical gaps of 1.23 and 1.13 eV, respectively. SWIR electroluminescence (EL) emission from OLEDs based on NTQ and BTQ is achieved, with emission peaks at 1140 and 1175 nm, respectively. Not only owing to a negligible efficiency roll‐off across the full range of applied current density but also the ability to afford a high operation current density of 5200 mA cm−2, the resultant SWIR OLEDs based on NTQ exhibit a maximal radiant exitance of =1.12 mW cm−2. Furthermore, the NTQ‐based OLEDs also possess sub‐gap turn‐on voltage of 0.85 V, which is close to the physical limits derived from the generalized Kirchhoff and Planck equation. This work demonstrates that A–D–A′–D–A type small molecules offer significant promise for NIR/SWIR emitting material innovations.