Unraveling the Structure-Property-Performance Relationships of Fused-Ring Nonfullerene Acceptors: Toward a C-Shaped ortho-Benzodipyrrole-Based Acceptor for Highly Efficient Organic Photovoltaics.

The high-performance Y6-based nonfullerene acceptors (NFAs) feature a C-shaped A-DA'D-A-type molecular architecture with a central electron-deficient thiadiazole (Tz) A' unit. In this work, we designed and synthesized a new A-D-A-type NFA, termed CB16, having a C-shaped ortho-benzodipyrrole-based skeleton of Y6 but with the Tz unit eliminated. When processed with nonhalogenated xylene without using any additives, the binary PM6:CB16 devices display a remarkable power conversion efficiency (PCE) of 18.32% with a high open-circuit voltage (Voc) of 0.92 V, surpassing the performance of the corresponding Y6-based devices. In contrast, similarly synthesized SB16, featuring an S-shaped para-benzodipyrrole-based skeleton, yields a low PCE of 0.15% due to the strong side-chain aggregation of SB16. The C-shaped A-DNBND-A skeleton in CB16 and the Y6-series NFAs constitutes the essential structural foundation for achieving exceptional device performance. The central Tz moiety or other A' units can be employed to finely adjust intermolecular interactions. The single-crystal X-ray structure reveals that ortho-benzodipyrrole-embedded A-DNBND-A plays an important role in the formation of a 3D elliptical network packing for efficient charge transport. Solution structures of the PM6:NFAs detected by small- and wide-angle X-ray scattering (SWAXS) indicate that removing the Tz unit in the C-shaped skeleton could reduce the self-packing of CB16, thereby enhancing the complexing and networking with PM6 in the spin-coating solution and the subsequent device film. Elucidating the structure-property-performance relationships of A-DA'D-A-type NFAs in this work paves the way for the future development of structurally simplified A-D-A-type NFAs.

Syntheses of Thioethers and Selenide Ethers from Anilines.

In this study, a general procedure was proposed for synthesizing thioethers and selenide ethers from anilines under solvent-free and transition-metal-free conditions. Thioethers were formed when anilines reacted with thiols under blue light-emitting-diode (LED) irradiation at room temperature without a photocatalyst. When reactions were performed using anilines and diselenides, the corresponding selenide ethers were obtained with satisfactory to excellent yields. The reaction was performed under photocatalyst-free and solvent-free conditions without blue LEDs. The advantages of this system include convenient operations, mild reaction conditions, satisfactory functional group tolerance, and late-stage selenylation of drug molecules.

CuI/Oxalic Diamide-Catalyzed Cross-Coupling of Thiols with Aryl Bromides and Chlorides.

We report a general copper-catalyzed cross-coupling of thiols with aryl halides by using N-aryl-N'-alkyl oxalic diamide (L3) or N,N'-dialkyl oxalic diamide (L5) as the ligand. Both aryl and alkyl thiols can be coupled with unactivated aryl bromides and chlorides to give the desired products in good yields. Furthermore, this system features a broad substrate scope and good tolerance of functional groups. Importantly, the oxalic diamides are stable and can be prepared easily from commercially available and cheap starting materials.