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A fused naphthodithiophene diimide (NDTI) derivative is first used as cathode interlayer materials (CIMs) in organic solar cells, by introducing two dimethylamine‐functionalized fluorenes on both sides, namely NDTI1. Meanwhile, two non‐fused naphthalene diimide (NDI) derivatives are synthesized as the control CIMs to validate the design strategy of fused NDI. All three CIMs show high thermal stability, robust adhesion, and strong electrode modification capability. Compared with two NDI‐based materials, NDTI1 possesses excellent film‐forming capacity and strong crystallinity, simultaneously. Besides, NDTI1 presents a strong self‐doping effect and distinct intermolecular interaction with non‐fullerene acceptors. As expected, the NDTI1‐based OSCs achieve a power conversion efficiency (PCE) of 18.02% using the PM6:Y6 active layer and a champion PCE of 19.01% employing the active layer PM6:L8‐BO, which is attributed to improve charge transport and extraction, and suppressive charge recombination. More importantly, NDTI1 retains 91% of the optimal PCE when the film thickness increases from 7 to 20 nm. Furthermore, NDTI1 also exhibits satisfactory universality for different active layer materials and excellent device stability. [ABSTRACT FROM AUTHOR]

Oligomeric acceptors are an effective π‐conjugate extension for small molecules because they effectively combine the advantages of polymeric and small molecular acceptors. The choice of linker group and oligomer position is however crucial for the efficient expression of π‐expansion advantages. Here, vinylene is chosen as the linker group and three oligomeric acceptors are produced with different connecting positions or end‐groups. Under illumination, the dimer acceptor dBTIC‐γV‐BO achieves the best power conversion efficiencies of 17.14% and a T80 lifetime of 2150 h amongst quasi‐planar heterojunction devices, which are much higher and more stable than the directly connected dimers dBTICγ‐EH or dBTIC‐δV‐BO. These results indicate that the oligomerization of small molecules with an appropriate linker group in the γ‐position is an effective strategy with which to improve the photovoltaic performance and stability of organic solar cells, and significantly promote their commercialization. [ABSTRACT FROM AUTHOR]

Herein, a novel D4 symmetrical redox‐active ligand tetrathia[8]circulene‐2,3,5,6,8,9,11,12‐octaol (8OH‐TTC) is designed and synthesized, which coordinates with Ni2+ ions to construct a 2D conductive metal‐organic framework (2D c‐MOF) named Ni‐TTC. Ni‐TTC exhibits typical semiconducting properties with electrical conductivity up to ≈1.0 S m−1 at 298 K. Furthermore, magnetism measurements show the paramagnetic property of Ni‐TTC with strong antiferromagnetic coupling due to the presence of semiquinone ligand radicals and Ni2+ sites. In virtue of its decent electrical conductivity and good redox activity, the gravimetric capacitance of Ni‐TTC is up to 249 F g−1 at a discharge rate of 0.2 A g−1, which demonstrates the potential of tetrathia[8]circulene‐based redox‐active 2D c‐MOFs in energy storage applications. [ABSTRACT FROM AUTHOR]

Strong intermolecular interactions usually facilitate charge transport, but impede photoluminescence, therefore, the development of organic π‐conjugated materials that exhibit both semiconducting and light‐emissive properties remains challenging. Herein, a series of perylene diimide (PDI)‐based carbolong complexes with dπ‐pπ conjugation is synthesized. The resulting alcohol‐soluble products exhibit broad and strong absorption combined with outstanding electronic and optical properties, and are applied as electron transport layer materials in organic solar cells, achieving power conversion efficiencies up to 17.36%. In addition, these complexes exhibit an uncommon aggregation‐induced emission phenomenon. These results will aid in future design of π‐conjugated materials with increased functionality. [ABSTRACT FROM AUTHOR]

In addition to efficiency, stability is another key factor in developing organic solar cells. The quasiplanar heterojunction (Q‐PHJ) structure, combining two pure layers as major and tiny nanoscale bulk heterojunction (BHJ) at interface, demonstrates superior device stability compared with BHJ devices. In this contribution, the polymer donor, PBQx‐H‐TF, and configurationally defined polymeric acceptor, PBTIC‐γ‐TSe are synthesized and used to fabricate bilayer devices by orthogonal solvents, the corresponding Q‐PHJ all‐polymer solar cells (all‐PSCs) deliver reliable stability with high efficiency. An encouraging PCE of 15.77% is achieved, which is the highest one among Q‐PHJ all‐PSCs with real‐bilayer structure. There is a major improvement over the 13.91% PCE in the BHJ device, and the carrier transport performance is improved substantially following the reduction of recombination in the Q‐PHJ all‐PSCs. Benefiting from the bilayer morphology, the stability of Q‐PHJ all‐PSCs has been greatly enhanced over that of the BHJ devices. The charge recombination process is also more serious in the aging BHJ compared with the aging Q‐PHJ all‐PSCs. This work inspires the application of Q‐PHJ in the preparation of high‐efficient all‐PSCs, but also provides guidance on the improvement of device stability from a dual approach of material and device engineering aspects. [ABSTRACT FROM AUTHOR]

The key issue for industrial large‐scale hydrogen production by water electrolysis is developing environment‐friendly electrocatalysts that can work well at large current densities and low overpotentials. Thanks to the superior advantages of 2D graphdiyne (GDY) on chemical structure and the alkyne bond strong reductivity, the highly selective, in situ growth of the single‐crystal Pd (111) quantum dots is achieved. The metal dots distribute uniformly and densely on the GDY surface (GDY‐Pd1) in a controllable way at low temperatures without adding additional reductive agents. Experimental and theoretical results show that the 2D GDY affords an ideal platform to construct highly selective and active electrocatalysts with accurate structures, defined valence states, facilitated charge transfer ability, and enhanced electric conductivity for hydrogen evolution reaction. Remarkably, the electrocatalyst can reach 500 and 1000 mA cm−2 at small overpotentials of only 201 and 261 mV, with high long‐term stability, which are better than most of the reported ones. The results demonstrate that 2D DGY is an excellent support in the controllable synthesis of metal quantum dots with well‐defined surface and structure and the potential to achieve large‐scale preparation. This study takes a critical step toward industrial hydrogen production. [ABSTRACT FROM AUTHOR]

Rational design and synthesis of non‐precious metal‐based electrocatalysts for efficient overall water splitting (OWS) in an integrated electrolyzer are of great significance for the development of hydrogen energy. To this end, nanowire‐structured heterogenous MnCo2O4/graphdiyne arrays are synthesized on the surface of 3D carbon cloth (NW‐MnCo2O4/GDY) by using in situ assembly and coupling strategy. Experiments demonstrated that the special core/shell‐nanowire structure and synergistic interaction between the MnCo2O4 and GDY can greatly improve the electric conductivity, facilitate the mass/ion transport and gas emissions, expose more active sites, and thus lead to the enhancement of the catalytic activity and long‐term stability of the electrocatalysts for OWS. For example, the alkaline water electrolyzer assembled by NW‐MnCo2O4/GDY shows high‐performance with only 1.47 and 1.60 V required to reach a current density of 10 and 100 mA cm−2, respectively, which is even better than that of previously reported electrocatalysts. [ABSTRACT FROM AUTHOR]

Systematic investigation of three nonfullerene acceptors, BTIC‐4Cl‐T, BTIC‐4Cl‐TCl‐γ, and BTIC‐4Cl‐TCl‐b, with or without a chlorine substituent at the γ/b‐position of the side chain thiophene ring, reveals that molecular planarity, stacking structure, and photovoltaic performance of the compounds are dependent on the position of the chlorine substituent. Of the materials using thiophenes in conjugated side chains, BTIC‐4Cl‐T shows a relatively lower open‐circuit voltage of 0.81 V, decreased current density, leading to an efficiency of only 10.86%. BTIC‐4Cl‐TCl‐γ with chlorine at the γ‐position of the conjugated thiophene shows a 3D network structure, a greatly increased current density, and an efficiency of 14.35%. BTIC‐4Cl‐TCl‐b, with a chlorine atom in b‐position, is found to have been reformed to a quasi‐3D network, in which electron hopping can be efficiently realized in adjacently positioned, linearly arranged molecules due to S···S interactions. With this quasi‐3D network, BTIC‐4Cl‐TCl‐b promotes the open‐circuit voltage up to 0.86 V and has the highest efficiency (15.65%) among the three acceptors. These results prove that chlorination is an effective strategy to improve photovoltaic performance and highlights the decisive relationship between structural regulation and molecular arrangement. It also provides a good starting point for the exploration and design of next generation high‐performance materials. [ABSTRACT FROM AUTHOR]

The highly planar molecular structure is conducive to electron delocalization, thus facilitating efficient charge transport. A new thiophene terminal‐linked dimerized small‐molecular acceptor (DSMA), DTY‐2Cl, is synthesized, which achieves high planarity with a bithiophene linkage. The results of theoretical calculation and single crystal analysis of regional configuration demonstrate that the twisting angle between the bithiophene binding unit of DTY‐2Cl is almost zero. Devices based on DTY‐2Cl:D18 show an outstanding photoelectric performance with a power conversion efficiency (PCE) of 18.06% and excellent device stability. It is worth noting that DTY‐2Cl exhibits a redshifted absorption of up to 840 nm, which is rare among DSMAs, and DTY‐2Cl‐based devices obtain a VOC of 0.913 V, thus achieving a win‐win situation of redshifted absorption and high VOC. These results indicate that using bithiophene instead of biphenyl to optimize the planarity of oligomer acceptors is an effective strategy and provide a new idea for the improvement of subsequent materials. [ABSTRACT FROM AUTHOR]