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The structure of molecular aggregates is crucial for charge transport and photovoltaic performance in organic solar cells (OSCs). Herein, the intermolecular interactions and aggregated structures of nonfused‐ring electron acceptors (NFREAs) are precisely regulated through a halogen transposition strategy, resulting in a noteworthy transformation from a 2D‐layered structure to a 3D‐interconnected packing network. Based on the 3D electron transport pathway, the binary and ternary devices deliver outstanding power conversion efficiencies (PCEs) of 17.46 % and 18.24 %, respectively, marking the highest value for NFREA‐based OSCs. [ABSTRACT FROM AUTHOR]

In the development of high‐performance organic solar cells (OSCs), the self‐organization of organic semiconductors plays a crucial role. This study focuses on the precisely manipulation of molecular assemble via tuning alkyl side‐chain topology in a series of low‐cost nonfused‐ring electron acceptors (NFREAs). Among the three NFREAs investigated, DPA‐4, which possesses an asymmetric alkyl side‐chain length, exhibits a tight packing in the crystal and high crystallinity in the film, contributing to improved electron mobility and favorable film morphology for DPA‐4. As a result, the OSC device based on DPA‐4 achieves an excellent power conversion efficiency of 16.67 %, ranking among the highest efficiencies for NFREA‐based OSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: By employing the asymmetric end‐group engineering, an asymmetric nonfused‐ring electron acceptor (NFREA) was designed and synthesized. Compared with the symmetric analogs (NoCA‐17 and NoCA‐18), NoCA‐19 possesses broader light absorption range, more coplanar π‐conjugated backbone, and appropriate crystallinity according to the experimental and theoretical results. The organic solar cells based on J52:NoCA‐19 exhibited a power conversion efficiency as high as 12.26%, which is much higher than those of J52:NoCA‐17 (9.50%) and J52:NoCA‐18 (11.77%), mainly due to more efficient exciton dissociation, better and balanced charge mobility, suppressed recombination loss, shorter charge extraction time, longer charge carrier lifetimes, and more favorable blend film morphology. These findings demonstrate the great potential of asymmetric end‐group engineering in exploring low‐cost and high‐performance NFREAs. [ABSTRACT FROM AUTHOR]

Developing an artificial visual sensory system requires optoelectronic materials and devices that can mimic the behavior of biological synapses. Organic/polymeric semiconductors have emerged as promising candidates for optoelectronic synapses due to their tunable optoelectronic properties, mechanic flexibility, and biological compatibility. In this review, we discuss the recent progress in organic optoelectronic synaptic materials and devices, including their design principles, working mechanisms, and applications. We also highlight the challenges and opportunities in this field and provide insights into potential applications of these materials and devices in next‐generation artificial visual systems. By leveraging the advances in organic optoelectronic materials and devices, we can envision its future development in artificial intelligence. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) have attracted extensive attention from both academia and industry in recent years due to their remarkable improvement in power conversion efficiency (PCE). However, the Golden Triangle (the balance of efficiency‐stability‐cost) required for large‐scale industrialization of OSCs still remains a great challenge. Here, a new nonfused‐ring electron acceptor (NFREA) BF and its polymerized counterpart PBF were designed and synthesized, and their photovoltaic performance, storage stability and material cost were systematically investigated. When blended with a widely‐used polymer donor PBDB‐T, the PBF‐based all‐polymer solar cell (all‐PSC) displayed a record high PCE of 12.61% for polymerized NFREAs (PNFREAs) with an excellent stability (95.2% of initial PCE after 800 h storage), superior to the BF counterpart. Impressively, PBF‐based all‐PSC possesses the highest industrial figure‐of‐merit (i‐FOM) value of 0.309 based on an efficiency‐stability‐cost evaluation, in comparison to several representative OSC systems (such as PM6:Y6 and PBDB‐T:PZ1). This work provides an insight into the balance of efficiency, stability, and cost, and also indicates that the PNFREAs are promising materials toward the commercial application of OSCs. [ABSTRACT FROM AUTHOR]

Novel passive devices such as all-optical diodes and all-optical logic gates require materials with appropriate both saturable and reverse saturable absorption properties. In this work, a series of GeSb4Te7 films were prepared by radio frequency magnetron sputtering and annealed at different temperatures to induce phase changes. Open-aperture Z-Scan experiments revealed that GeSb4Te7 films featured a large nonlinear absorption coefficient that varied with the extent of phase change induced by the annealing temperature. To understand the underlying reason, a three-level model was developed to explain the competition between ground-state absorption and excited-state absorption during the process. The large nonlinear absorption coefficient of GeSb4Te7 films ( β eff = - 20368.90 cm/GW) shows that ternary material demonstrates outstanding nonlinear optical absorption capability. Impressively, the annealing treatment induced microstructural changes in the GeSb4Te7 films that caused a transition from reverse saturable absorption to saturable absorption, offering great potential for innovative passive nonlinear optical devices. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: By employing thiazole and 4‐chlorothiazole as the A′ units, two A‐D‐A′‐D‐A type nonfused‐ring electron acceptors (NFREAs) Tz‐H and Tz‐Cl were designed and synthesized. Replacing thiazole in Tz‐H with 4‐chlorothiazole can not only remarkably shorten the synthetic route through C—H direct arylation but also enhance molecular planarity with the simultaneous incorporation of S···N and S···Cl noncovalently conformational locks (NoCLs). The photovoltaic devices based on PM6:Tz‐Cl exhibited a power conversion efficiency as high as 11.10%, much higher than that of PM6:Tz‐H (6.41%), mainly due to more efficient exciton dissociation, better and more balanced carrier mobility, less charge recombination, and more favorable morphology. These findings demonstrate the great potential of NoCLs in achieving low‐cost and high‐performance NFREAs. [ABSTRACT FROM AUTHOR]

The power conversion efficiencies (PCEs) of all‐polymer solar cells (all‐PSCs) have already exceeded 17%. However, the limited absorption range of an all‐polymer system results in significantly reduced short‐circuit current density (Jsc), which eventually influences the PCE improvement. To broaden the light absorption of polymer acceptors, herein, benzotriazole is introduced in the core unit of small molecule acceptors and thus two narrow‐bandgap polymer acceptors named PTz‐BO and PTz‐C11 featuring the same molecular backbone and different side‐chain length are synthesized. Compared with PTz‐C11, the PTz‐BO based‐all PSCs deliver a slightly reduced Jsc, a large open‐circuit voltage (Voc) and a low voltage loss below 0.50 V. Moreover, ternary all‐PSCs are constructed by introducing PTz‐C11 as a guest component. Benefiting from the reduced recombination, improved exciton generation and dissociation, and balanced charge transport, a high efficiency of 16.58% is obtained for the ternary all‐PSCs, with a high Jsc over 25 mA cm−2 without sacrificing the Voc. Such result represents the highest efficiency reported for benzotriazole‐based all‐PSCs in the literature thus far. This work demonstrates the great potential of benzotriazole for the synthesis of efficient narrow‐bandgap polymer acceptors. [ABSTRACT FROM AUTHOR]

Morphological stability is crucially important for the long‐term stability of polymer solar cells (PSCs). Many high‐efficiency PSCs suffer from metastable morphology, resulting in severe device degradation. Here, a series of copolymers is developed by manipulating the content of chlorinated benzodithiophene‐4,8‐dione (T1‐Cl) via a random copolymerization approach. It is found that all the copolymers can self‐assemble into a fibril nanostructure in films. By altering the T1‐Cl content, the polymer crystallinity and fibril width can be effectively controlled. When blended with several nonfullerene acceptors, such as TTPTT‐4F, O‐INIC3, EH‐INIC3, and Y6, the optimized fibril interpenetrating morphology can not only favor charge transport, but also inhibit the unfavorable molecular diffusion and aggregation in active layers, leading to excellent morphological stability. The work demonstrates the importance of optimization of fibril network morphology in realizing high‐efficiency and ambient‐stable PSCs, and also provides new insights into the effect of chemical structure on the fibril network morphology and photovoltaic performance of PSCs. [ABSTRACT FROM AUTHOR]

The development of semitransparent organic solar cells (ST‐OSCs) represents a significant step toward the commercialization of OSCs. However, the trade‐off between power conversion efficiency (PCE) and average visible transmittance (AVT) restricts further improvements of ST‐OSCs. Herein, it is demonstrated that a fibril network strategy can enable ST‐OSCs with a high PCE and AVT simultaneously. A wide‐bandgap polymer PBT1‐C‐2Cl that can self‐assemble into a fibril nanostructure is used as the donor and a near‐infrared small molecule Y6 is adopted as the acceptor. It is found that a tiny amount of PBT1‐C‐2Cl in the blend can form a high speed pathway for hole transport due to the well distributed fibril nanostructure, which increases the transmittance in the visible region. Meanwhile, the acceptor Y6 guarantees sufficient light absorption. Using this strategy, the optimized ST‐OSCs yield a high PCE of 9.1% with an AVT of over 40% and significant light utilization efficiency of 3.65% at donor/acceptor ratio of 0.25:1. This work demonstrates a simple and effective approach to realizing high PCE and AVT of ST‐OSCs simultaneously. [ABSTRACT FROM AUTHOR]

This article discusses the challenge of industrializing organic solar cells and the need to balance efficiency, stability, and cost. The authors present a polymer acceptor called PBF, which was created using a polymerized nonfused-ring electron acceptor strategy. This polymer acceptor achieved a high efficiency of 12.61%, excellent stability, and low cost, making it a promising option for industrial applications. The authors compare the performance of PBF to other reputable systems and highlight its superior figure-of-merit. [Extracted from the article]

A novel strategy involving judiciously fusing one thiophene/thieno[3,2-b]thiophene on only one side of an indacenodithiophene (IDT) unit to extend IDT backbone conjugation was developed, and three A–D–A type non-fullerene small molecules (TPT-2F, TPTT-2F, and TPTTT-2F) were designed and synthesized to investigate the influence of the extent of IDT core conjugation on their photovoltaic properties. Extending the IDT core conjugation could broaden absorption, upshift the lowest unoccupied molecular orbital (LUMO) energy level, enhance electron mobility, and increase intermolecular π–π stacking. When these three non-fullerene acceptors were applied in organic solar cells (OSCs), simultaneous enhancement of the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) was obtained, with the degree of enhancement following the order TPT-2F ＜ TPTT-2F ＜ TPTTT-2F. As a result, the TPTTT-2F based OSCs yielded a high PCE of 12.03%. To the best of our knowledge, the PCE of 12.03% is among the highest values for asymmetric non-fullerene acceptor based OSCs so far. These results demonstrate that extending the conjugation of the IDT core is an effective approach to design highly efficient asymmetric non-fullerene acceptors. [ABSTRACT FROM AUTHOR]

In this work, we demonstrated the synthesis and characterization of two novel donor–acceptor type conjugated polymers, IDT-T1 and IDTT-T1, which consist of indacenodithiophene (IDT) and indacenodithieno[3,2-b]thiophene (IDTT) donor and 1,3-bis(5-bromothiophen-2-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c]dithiophene-4,8-dione (T1) acceptor building blocks. The resulting copolymers exhibited a wide bandgap of about 1.90 eV with a comparatively low-lying highest occupied molecular orbital (HOMO) energy level. However, IDTT-T1 with an extended fused-ring unit was found to have better coplanarity and higher carrier mobility (0.11 cm2 V−1 s−1). As a consequence, organic solar cells employing IDTT-T1 as the donor material afforded a power conversion efficiency (PCE) of 6.58%, while IDT-T1-based devices yielded a relatively lower PCE of 6.26%. [ABSTRACT FROM AUTHOR]

A new 3D-structured acceptor TP3, in which three perylene diimide (PDI) units are connected together by a triptycene (TPC) core, is synthesized and characterized. Organic solar cells (OSCs) fabricated with a PTB7-Th:TP3 blend film as the active layer have been investigated and the best power conversion efficiency (PCE) of 3.16% is achieved by adding 0.5% DIO. Our studies suggest that the introduction of the TPC core could suppress the strong self-aggregation tendency of the PDI chromophores. [ABSTRACT FROM AUTHOR]

Ternary structures are demonstrated as a promising approach to increase the efficiency and light harvesting of solar cells. A high power conversion efficiency of 10.2% is achieved for ternary organic solar cells with two efficient polymer donors. The improved performance is attributed to the synergistic effects of enhanced light absorption and charge transport, efficient energy transfer, improved charge generation and morphology. [ABSTRACT FROM AUTHOR]

A twisted bay‐substituted tetraphenyl functionalized perylenediimide monomer (TP‐PDI) is synthesized. A high power conversion efficiency of 4.1% is achieved for organic solar cells incorporated a combination of TP‐PDI electron acceptor and PTB7‐Th electron donor, indicating that chemical modification of PDI monomers is a useful way of designing high‐performance non‐fullerene electron acceptors. [ABSTRACT FROM AUTHOR]