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The achievement of high performance in organic solar cells (OSCs) is highly dependent on efficient exciton dissociation. However, a comprehensive understanding of the exciton dissociation process under photoexcitation in OSCs remains elusive. Herein, a prototypical system of PM6:Y6 is adopted to explore the exciton dissociation process. An organic semiconductor PCz with distinctive photoexcitation signals from PM6 and Y6 is incorporated as the third component. Femtosecond transient absorption spectroscopy demonstrates clear cascade charge transfer processes in ternary PM6:PCz:Y6 system. These cascade channels contribute to enhancing the efficiency of exciton dissociation. Consequently, the nonradiative recombination energy loss is reduced, resulting in an improved power conversion efficiency (PCE) of OSCs. Furthermore, the reduction of energy loss is verified in different OSCs. When PCz is introduced into the D18:L8‐BO system, a low nonradiative recombination energy loss of 0.175 eV is demonstrated, contributing a PCE of over 19%. This work highlights that the insight of efficient exciton dissociation enables low nonradiative recombination losses for efficient OSCs. [ABSTRACT FROM AUTHOR]

The side‐chain has a significant influence on the optical properties and aggregation behaviors of the organic small molecule acceptors, which becomes an important strategy to optimize the photovoltaic performance of organic solar cells. In this work, we designed and synthesized three brand‐new nonfused ring electron acceptors (NFREAs) OC4‐4Cl‐Ph, OC4‐4Cl‐Th, and OC4‐4Cl‐C8 with hexylbenzene, hexylthiophene, and octyl side chains on the π‐bridge units. Compared with OC4‐4Cl‐Ph and OC4‐4Cl‐Th, OC4‐4Cl‐C8 with linear alkyl side chain has more red‐shift absorption, which is conducive to obtaining higher short‐circuit current density. Additionally, the OC4‐4Cl‐C8 film exhibits a longer exciton diffusion distance, and the D18:OC4‐4Cl‐C8 blend film displays faster hole transfer, weaker bimolecular recombination, and more efficient exciton transport. Furthermore, The D18:OC4‐4Cl‐C8 blend films may effectively form interpenetrating networks that resemble nanofibrils, which can facilitate exciton dissociation and charge transport. Finally, OC4‐4Cl‐C8‐based devices can be created a marvellously power conversion efficiency (PCE) of 16.56%, which is much higher than OC4‐4Cl‐Ph (12.29%)‐ and OC4‐4Cl‐Th‐based (11.00%) ones, being the highest PCE among the NFREA based binary devices. All in all, we have validated that side‐chain engineering is an efficient way to achieve high‐performance NFREAs. [ABSTRACT FROM AUTHOR]

The ternary strategy has proven to be an effective method for improving the efficiency of organic solar cells (OSCs). However, designing and selecting the third component still pose challenges. In this study, this issue is addressed by focusing on the PBDB‐T:Y18‐F binary system and introducing a new, strong luminescent, asymmetric small‐molecule acceptor (SMA) called L8‐CBIC‐Cl, which shares a similar skeleton with Y18‐F. The similarity in molecular framework facilitates good compatibility between the two acceptors, resulting in the formation of an alloy‐like acceptor phase. Furthermore, the norbornenyl‐modified end group in L8‐CBIC‐Cl contributes to its strong luminescent properties, which in turn leads to a low non‐radiative energy loss and a high open‐circuit voltage. Consequently, the PBDB‐T:L8‐CBIC‐Cl:Y18‐F based ternary devices realize a high power conversion efficiency (PCE) up to 17.01%, which is higher than PBDB‐T:Y18‐F device (14.49%). Importantly, L8‐CBIC‐Cl exhibits a good universality as a guest acceptor in other three binary systems (D18:Y6, D18:BTP‐eC9‐4F, and D18:L8‐BO). The D18:L8‐BO:L8‐CBIC‐Cl device shows an impressive efficiency of 19%. The work demonstrates that employing SMA with a high PLQY and better miscibility with host acceptor as the third component has a great potential for developing high‐efficiency ternary OSCs. [ABSTRACT FROM AUTHOR]

Utilizing intermolecular hydrogen‐bonding interactions stands for an effective approach in advancing the efficiency and stability of small‐molecule acceptors (SMAs) for polymer solar cells. Herein, we synthesized three SMAs (Qo1, Qo2, and Qo3) using indeno[1,2‐b]quinoxalin‐11‐one (Qox) as the electron‐deficient group, with the incorporation of a methylation strategy. Through crystallographic analysis, it is observed that two Qox‐based methylated acceptors (Qo2 and Qo3) exhibit multiple hydrogen bond‐assisted 3D network transport structures, in contrast to the 2D transport structure observed in gem‐dichlorinated counterpart (Qo4). Notably, Qo2 exhibits multiple and stronger hydrogen‐bonding interactions compared with Qo3. Consequently, PM6 : Qo2 device realizes the highest power conversion efficiency (PCE) of 18.4 %, surpassing the efficiencies of devices based on Qo1 (15.8 %), Qo3 (16.7 %), and Qo4 (2.4 %). This remarkable PCE in PM6 : Qo2 device can be primarily ascribed to the enhanced donor‐acceptor miscibility, more favorable medium structure, and more efficient charge transfer and collection behavior. Moreover, the PM6 : Qo2 device demonstrates exceptional thermal stability, retaining 82.8 % of its initial PCE after undergoing annealing at 65 °C for 250 hours. Our research showcases that precise methylation, particularly targeting the formation of intermolecular hydrogen‐bonding interactions to tune crystal packing patterns, represents a promising strategy in the molecular design of efficient and stable SMAs. [ABSTRACT FROM AUTHOR]

In this work, inspired by the principles of a pressure cooker, we utilized a high‐pressure method to address the processing challenges associated with high molecular weight polymers. Through this approach, we successfully dissolved high molecular weight D18 in chloroform at 100 °C within a pressure‐tight vial. The increased steam pressure raised the boiling point and dissolving capacity of chloroform, enabling the creation of a hybrid film with superior properties, including more ordered molecular arrangement, increased crystallinity, extended exciton diffusion length, and improved phase morphology. Organic solar cells (OSCs) based on D18 : L8‐BO prepared using this high‐pressure method achieved an outstanding power conversion efficiency of 19.65 %, setting a new record for binary devices to date. Furthermore, this high‐pressure method was successfully applied to fabricate OSCs based on other common systems, leading to significant enhancements in device performance. In summary, this research introduces a universal method for processing high molecular weight D18 materials, ultimately resulting in the highest performance reported for binary organic solar cells. [ABSTRACT FROM AUTHOR]

High‐boiling‐point solvents are considered to be decent solvents for the preparation of large‐area organic solar cells (OSCs) because of their wide processing window. However, the efficiency of OSCs processed by high‐boiling‐point solvents is still unsatisfactory. Herein, it is found that the agglomerate growth of nonfullerene acceptors into micrometer‐sized domains is the main reason for poor efficiency. A facile rapid molding process (RMP) scheme is proposed to solve this problem by adjusting the nucleation and growth behavior of acceptor molecules. RMP enables the blend films with interpenetrating networks and higher crystallinity, which is in favor of faster exciton separation and lower recombination losses. As a result, the power convention efficiency (PCE) is improved from 15.91% (reference) to 18.32% (RMP) for PL1:BTP‐eC9‐4F OSCs. To the best of the authors' knowledge, this is the champion efficiency of OSCs processed with high‐boiling‐point solvents. Meanwhile, RMP devices maintain 85% or 90% of the initial PCE after real day/night cycling in the air for over 2000 h or after continuous thermal aging at 85 °C in nitrogen for 500 h, respectively. [ABSTRACT FROM AUTHOR]

Although the advances in organic solar cells (OSCs) have been considerable, their efficiency is still limited by recombination losses. Photogenerated electrons and holes are generally bound as localized excitons in organic semiconductors. The transition from excitons into free charges requires diffusion and dissociation processes, in which parasitic recombination losses exist. Reducing these losses is necessary for highly efficient OSCs. The crystallization behavior of the active layers can influence the efficiency of exciton diffusion and dissociation. In this work, different additives are delicately designed to control the crystallization behavior. It is found that the crystallization quality of active layers can be improved by controlling the aggregation of nonfullerene acceptors. The π–π stacking of blend films becomes compact, meanwhile, the crystallization in the vertical direction is more uniform. These are beneficial to the diffusion and dissociation of excitons. As a consequence, recombination losses are reduced and power convention efficiencies (PCEs) are improved significantly. Meanwhile, the general applicability of the additive is demonstrated in various organic photovoltaic systems, in which a PCE of 19.3% is achieved in D18:BTP‐eC9‐4F OSCs. This work provides a facile strategy to reduce the recombination losses of excitons for efficient devices. [ABSTRACT FROM AUTHOR]

Nowadays, it is still a great challenge to obtain high‐performance green‐solvent‐processed organic solar cells (OSCs). In this study, a ternary blend strategy (one donor and two acceptors, 1D/2A) is developed to solve the difficulty of film morphology modulation during the fabrication of high‐performance green‐solvent‐processed OSCs. A typical high‐performance halogenated‐solvent processable binary system D18:BTP‐eC9‐4F is selected as the host, its green‐solvents‐processed devices show an inferior power conversion efficiency (PCE) of ≈16%. SM16 with two 3D shape persistent end groups is selected as the third component due to its high fluorescence quantum yield, reduced intermolecular interaction, good solubility, and moderate crystallinity. As a result, the ternary devices display bicontinuous interpenetrating networks, reduced energy loss, and suppressed charge carrier recombination losses. Hence, an excellent PCE of 18.20% is achieved for the D18:BTP‐eC9‐4F:SM16 ternary devices, which is much higher than D18:BTP‐eC9‐4F‐based binary ones and also one of the highest PCEs for the green‐solvents‐processed OSCs. Besides, this strategy also demonstrates a good universality for other binary systems and becomes an effective pathway for the development of green‐solvent processable high‐performance OSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: By simplifying the π‐bridge unit, a nonfused ring electron acceptor (NFREA) BM‐2F was designed and synthesized with several high‐yield steps. The specific molecular structure features of BM‐2F are planar molecular backbone and out‐of‐plane side chain, which is favorable for charge transport and can suppress the over‐aggregation. BM‐2F based neat and blend films display obvious face‐on molecular orientation. Specially, D18:BM‐2F based blend film can form good bicontinuous interpenetrating network. More excitingly, a power conversion efficiency of 16.15% was achieved with D18:BM‐2F based photovoltaic devices, which is the highest one based on NFREAs. Our researches manifest that NFREA is a promising direction for low‐cost and high‐performance organic solar cells. [ABSTRACT FROM AUTHOR]

Functionalization of ligated metal nanoclusters with versatile ligands is highly desired for wide applications. Lewis acids have shown promise in multiple realms such as self‐assembly and catalysis, which may endow nanoclusters with diverse functions. However, metal nanoclusters with Lewis acid surface have not been reported. Here, the functionalization of a bimetallic nanocluster Au8Ag8(CCR)16 with triarylborane (TAB) is reported, which exhibits enhanced Lewis acidity. By using single‐crystal X‐ray crystallography, the structure of the nanocluster with 16 boron receptor sites is confirmed, which presents ≈15‐fold enhancement of quenching efficiency in sensing fluoride compared to that of free triarylborane ligand. By the combined analysis using ultrafast transient absorption and photoluminescent (PL) decay measurements, the quenching mechanism of Au8Ag8 to fluoride is elucidated. The PL quenching is realized via two pathways with enhanced non‐radiation energy dissipation, i.e., prolonged electron–phonon coupling and reverse intersystem crossing (RISC). This work may open a new route to diverse applications of metal nanoclusters. [ABSTRACT FROM AUTHOR]

Three terpolymer donors (PL1, PL2, and PL3) employing repeating units of two popular photovoltaic polymers PM6 and D18 are synthesized by random copolymerization. The terpolymers can reduce the regio‐regularity of the polymer backbones and endow them with much‐enhanced solubility in nonhalogenated solvents such as o‐xylene. Furthermore, along with the appearance of temperature‐dependent aggregation behavior, indicating the adaptability for fabricating organic solar cells (OSCs) by eco‐friendly solvent processing. Among them, PL1‐based OSCs display higher and more balanced hole and electron mobilities, longer charge separation exciton lifetime, and better exciton dissociation and charge collection capabilities than the parent polymers (PM6 and D18) based ones. A power conversion efficiency of 18.14% with a very low energy loss is achieved based on terpolymer PL1, which is much higher than that of PM6 (15.16%) and D18 (16.18%). The result provides an effective way to realize high‐performance nonhalogenated processing polymer donor materials. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is a non‐invasive treatment modality against a range of cancers and nonmalignant diseases, however one must be aware of the risk of causing phototoxic reactions after treatment. We herein report a bioinspired design of next‐generation photosensitizers (PSs) that not only effectively produce ROS but undergo fast metabolism after treatment to overcome undesirable side effects. We constructed a series of β‐pyrrolic ring‐opening seco‐chlorins, termed beidaphyrin (BP), beidapholactone (BPL), and their zinc(II) derivatives (ZnBP and ZnBPL), featuring intense near‐infrared absorption and effective O2 photosensitization. Irradiation of ZnBPL led to a non‐cytotoxic, metabolizable beidaphodiacetamide (ZnBPD) via in situ generated O2.− but not 1O2, as revealed by mechanistic studies including time‐resolved absorption, kinetics, and isotope labeling. Furthermore, water‐soluble ZnBPL showed an effective therapeutic outcome, fast metabolism, and negligible phototoxic reactions. [ABSTRACT FROM AUTHOR]

The ionic nature of organic trihalide perovskite leads to structural irregularity and energy disorder at the perovskite surface, which seriously affects the photovoltaic performance of perovskite solar cells. Here, the origin of the perovskite surface disorder is analyzed, and a facial ion‐exchange strategy is designed to regulate the surface chemical environment. By the reconstruction of terminal irregular Pb–I bonds and random cations, the repaired surface is characteristic of the reduced band tail states, consequent to the suppression of the uplift of quasi‐Fermi level splitting and photocarrier scattering. The optimized device gets a high open‐circuit voltage and operational stability. These findings fully elaborate the underlying mechanism concerning perovskite surface problem, giving guidance on tailoring the energy disorder. [ABSTRACT FROM AUTHOR]

Reducing non‐radiative energy loss (∆Enr) is critical for enhancing the photovoltaic performance of organic solar cells (OSCs). To achieve this, a small molecular donor, LJ1, is introduced as the third component in the host system D: A system (D18: BTP‐eC9‐4F). The cascade‐like energy level alignment of D18, LJ1, and BTP‐eC9‐4F facilitates efficient charge transfer. LJ1's good solubility in the processing solvent and high miscibility with BTP‐eC9‐4F delay the precipitation of BTP‐eC9‐4F, leading to improved phase morphology in blend films. Additionally, LJ1 increases spacing between the polymer donor (PD) and the small molecule acceptor (SMA), optimizing blend film morphology and reducing non‐radiative energy loss in OSCs. Ternary OSCs based on D18:LJ1:BTP‐eC9‐4F achieve a power conversion efficiency (PCE) of 19.43% with reduced ∆Enr. Notably, the ternary device using D18:LJ1:L8‐BO attains an outstanding PCE of 19.78%, which is one of the highest device efficiency for ternary OSC. The work highlights the effectiveness of the ternary blend strategy in enhancing OSC performance while minimizing ∆Enr. [ABSTRACT FROM AUTHOR]

Designing and synthesizing narrow band gap acceptors that exhibit high photoluminescence quantum yield (PLQY) and strong crystallinity is a highly effective, yet challenging, approach to reducing non‐radiative energy losses (▵Enr) and boosting the performance of organic solar cells (OSCs). We have successfully designed and synthesized an A–D–A type fused‐ring electron acceptor, named DM‐F, which features a planar molecular backbone adorned with bulky three‐dimensional camphane side groups at its central core. These bulky substituents effectively hinder the formation of H‐aggregates of the acceptors, promoting the formation of more J‐aggregates and notably elevating the PLQY of the acceptor in the film. As anticipated, DM‐F showcases pronounced near‐infrared absorption coupled with impressive crystallinity. Organic solar cells (OSCs) leveraging DM‐F exhibit a high EQEEL value and remarkably low ▵Enr of 0.14 eV‐currently the most minimal reported value for OSCs. Moreover, the power conversion efficiency (PCE) of binary and ternary OSCs utilizing DM‐F has reached 16.16 % and 20.09 %, respectively, marking a new apex in reported efficiency within the OSCs field. In conclusion, our study reveals that designing narrow band gap acceptors with high PLQY is an effective way to reduce ▵Enr and improve the PCE of OSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: By simplifying the π‐bridge unit, a nonfused ring electron acceptor (NFREA) BM‐2F was designed and synthesized with several high‐yield steps. The specific molecular structure features of BM‐2F are planar molecular backbone and out‐of‐plane side chain, which is favorable for charge transport and can suppress the over‐aggregation. BM‐2F based neat and blend films display obvious face‐on molecular orientation. Specially, D18:BM‐2F based blend film can form good bicontinuous interpenetrating network. More excitingly, a power conversion efficiency of 16.15% was achieved with D18:BM‐2F based photovoltaic devices, which is the highest one based on NFREAs. Our researches manifest that NFREA is a promising direction for low‐cost and high‐performance organic solar cells. [ABSTRACT FROM AUTHOR]