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The quinoid-donor-acceptor (Q-D-A) strategy has recently emerged as a promising approach for constructing high mobility semiconducting polymers. In order to fully explore the potential of this strategy in improving the charge transport and elucidating the structure-property-performance relationships in Q-D-A polymers, a series of new polymers with different electron acceptor units and backbone coplanarity have been synthesized and characterized. All of the resulting Q-D-A polymers exhibit much more planar backbone conformations in comparison to their donor-acceptor (D-A) counterparts. Moreover, organic field-effect transistors based on Q-D-A polymers exhibit excellent effective hole mobilities in a range of 0.44 to 3.35 cm2 V−1 s−1, most of which are orders of magnitude higher than those of their corresponding D-A polymers. Notably, the hole mobility of 3.35 cm2 V−1 s−1 is among the highest for the quinoidal-aromatic polymers characterized by conventional spin-coating methods. Furthermore, the role of electron acceptors in Q-D-A polymers has been comprehensively investigated. Polymers with stronger acceptor units are more inclined to deliver edge-on lamellas, high film crystallinity, small effective hole masses, and decent operational stability. The detailed structure-property-device performance relationship will pave the way toward high performance semiconducting polymers using the potent Q-D-A strategy.

The Zn2+ sluggish kinetics resulting from high desolvation barriers of Zn(H2O)62+ in the electrode/electrolyte interface restricts the practical application of Zn‐ion batteries (ZIBs). Herein, ethylene glycol (EG) molecules are inserted into V2O5·3H2O to form V‐EG nanoarray structures to improve the Zn2+ diffusion rate. Unlike most efforts focused on improving interlayer spacing and structural stability, the influence of EG on the Zn2+ desolvation and Zn2+ storage process are the main goals. Based on experimental and theoretical analysis, EG molecules are confirmed to participate in the reshaping of V2O5·3H2O morphology and Zn2+ solvation structure, which is beneficial to enhance the reaction kinetics and specific capacity. The polar group of the EG molecule leads it anchored in the VO skeleton and decreases the desolvation energy, while the steric hindrance of the low polarity group liberalizes Zn2+ transfer reversibly in the VO skeleton. Therefore, V‐EG delivers a higher ion diffusion coefficient and lower kinetic barrier. As expected, V‐EG exhibits a high specific capacity of 553 mA h g−1 at 0.3 A g−1 and a long cycle life of 10 000 cycles at 20 A g−1. This work provides a strategy to decrease the desolvation energy of Zn2+ in the interface of cathode materials toward advanced ZIBs. [ABSTRACT FROM AUTHOR]

Artificial photosynthesis, which converts carbon dioxide into hydrocarbon fuels, is a promising strategy to overcome both global warming and energy crisis. Herein, the geometric position of Cu and Ga on ultra‐thin CuGaS2/Ga2S3 is oriented via a sulfur defect engineering, and the unprecedented C2H4 yield selectivity is ≈93.87% and yield is ≈335.67 µmol g−1 h−1. A highly delocalized electron distribution intensity induced by S vacancy indicates that Cu and Ga adjacent to S vacancy form Cu–Ga metallic bond, which accelerates the photocatalytic reduction of CO2 to C2H4. The stability of the crucial intermediates (*CHOHCO) is attributed to the upshift of the d‐band center of ultra‐thin CGS/GS. The C–C coupling barrier is intrinsically reduced by the dominant exposed Cu atoms on the 2D ultra‐thin CuGaS2/Ga2S3 in the process of photocatalytic CO2 reduction, which captures *CO molecules effectively. This study proposes a new strategy to design photocatalyst through defect engineering to adjust the selectivity of photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

Artificial photosynthesis, which converts carbon dioxide into hydrocarbon fuels, is a promising strategy to overcome both global warming and energy crisis. Herein, the geometric position of Cu and Ga on ultra‐thin CuGaS2/Ga2S3 is oriented via a sulfur defect engineering, and the unprecedented C2H4 yield selectivity is ≈93.87% and yield is ≈335.67 µmol g−1 h−1. A highly delocalized electron distribution intensity induced by S vacancy indicates that Cu and Ga adjacent to S vacancy form Cu–Ga metallic bond, which accelerates the photocatalytic reduction of CO2 to C2H4. The stability of the crucial intermediates (*CHOHCO) is attributed to the upshift of the d‐band center of ultra‐thin CGS/GS. The C–C coupling barrier is intrinsically reduced by the dominant exposed Cu atoms on the 2D ultra‐thin CuGaS2/Ga2S3 in the process of photocatalytic CO2 reduction, which captures *CO molecules effectively. This study proposes a new strategy to design photocatalyst through defect engineering to adjust the selectivity of photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

Constructing proper in vitro tumor immune microenvironment (TIME) is important for cancer immune‐therapy studies, while the selection of biomaterials is critical. As innate immune cells, macrophages can target and kill cancer cells in vivo at the early stage of tumor development. However, this targeting phenomenon has not been observed in vitro. Herein, a quasi‐3D in vitro cell culture model is constructed to mimic TIME by integrating hydrogel collagen as extracellular matrix for cells. In the collagen‐based quasi‐3D in vitro system, for the first time, it is found that macrophages can be attracted toward cancer cells along the dynamically reconstructed collagen fibers. By combining traction force microscopy and customized micro‐manipulator system, it is revealed that the collagen matrix‐transmitted tensile force signaling precisely guides the migration of macrophages toward cancer cells. The mechano‐responsiveness mechanism is related to the activation of mechanosensitive ion channels, and the induced local increase of calcium signal, which is proved to enhance the F‐actin assembly and to guide the cell migration. This novel mechanism advances the understanding of the role of collagen fibers in mechanotaxis of macrophages. Taken together, it has great potential for assisting biomaterial designs in developing new drug‐screening models and clinical strategies for cancer immune‐therapy. [ABSTRACT FROM AUTHOR]

To enhance the energy density of batteries and explore intrinsic charge storage mechanism of the active materials, it is important to reduce or eliminate the use of non‐active materials in electrodes, such as binder and conductive additives. Herein, free‐standing Na4MnV(PO4)3@C (F‐NMVP@C) fiber membrane is fabricated and directly used as a sodium‐ion battery (SIB) cathode. In situ X‐ray diffraction reveals that the V3+/V4+ redox reaction occurs through a solid‐solution reaction while a two‐phase Mn2+/Mn3+ redox reaction is identified, and both are highly reversible. Meanwhile, ex situ electrochemical impedance spectroscopy reveals that both the ion diffusion coefficient and charge transfer resistance of F‐NMVP@C change reversibly during the Na+ intercalation/de‐intercalation. Battery full cells are assembled based on the free‐standing F‐NMVP@C cathodes and F‐Sb@C anodes, which manifests a high energy density (293 Wh kg−1) and good cyclability (87.5% after 100 cycles at 1 C). The high‐performance free‐standing cathodes and anodes shed light on the development of flexible SIBs. [ABSTRACT FROM AUTHOR]

The crystal orientation of small molecules is one of the key parameters for developing high‐performance small molecule based organic field‐effect transistors. However, achieving a high degree of backbone alignment still remains a challenge, due to the sensitive nature of small molecules to processing conditions. Herein, the thin films of three conjugated small molecules, named as ZR1, ZR2‐C3, and Y6 are prepared by epitaxial‐crystallization on a highly oriented polyethylene (PE) substrate, resulting in the significant enhancement in charge transport properties. The maximum mobilities for aligned edge‐on molecules in the films enhance by up to 9.91 × 10−2 and 8.97 × 10−2 cm2 V−1s−1 for ZR1 and ZR2‐C3 films with conducting channel along small molecule backbones, which are 35‐ and 37‐fold that of the values evaluated in perpendicular to molecular backbones and nearly 23‐and 19‐fold beyond the values measured from unaligned films. Furthermore, the electron and hole mobilities of the small molecule Y6 with face‐on nature increase by nearly fourfold the values measured in perpendicular to the backbone direction and from unaligned films. This work demonstrates the epitaxial crystallization of thin films on oriented PE, offers a critical understanding of small molecules with different orientations and an effective approach for tuning charge transport toward high‐performance organic electronic applications. [ABSTRACT FROM AUTHOR]

Van der Waals p–n junctions of 2D materials present great potential for electronic devices due to the fascinating properties at the junction interface. In this work, an efficient gas sensor based on planar 2D van der Waals junctions is reported by stacking n‐type and p‐type atomically thin MoS2 films, which are synthesized by chemical vapor deposition (CVD) and soft‐chemistry route, respectively. The electrical conductivity of the van der Waals p–n junctions is found to be strongly affected by the exposure to NO2 at room temperature (RT). The MoS2 p–n junction sensor exhibits an outstanding sensitivity and selectivity to NO2 at RT, which are unavailable in sensors based on individual n‐type or p‐type MoS2. The sensitivity of 20 ppm NO2 is improved by 60 times compared to a p‐type MoS2 sensor, and an extremely low limit of detection of 8 ppb is obtained under ultraviolet irradiation. Complete and very fast sensor recovery is achieved within 30 s. These results are superior to most of the previous reports related to NO2 detection. This work establishes an entirely new sensing platform and proves the feasibility of using such materials for the high‐performance detection of gaseous molecules at RT. [ABSTRACT FROM AUTHOR]

In this work, for the first time, the addition of aluminum oxide nanostructures (Al2O3 NSs) grown by glancing angle deposition (GLAD) is investigated on an ultrathin Cu(In,Ga)Se2 device (400 nm) fabricated using a sequential process, i.e., post‐selenization of the metallic precursor layer. The most striking observation to emerge from this study is the alleviation of phase separation after adding the Al2O3 NSs with improved Se diffusion into the non‐uniformed metallic precursor due to the surface roughness resulting from the Al2O3 NSs. In addition, the raised Na concentration at the rear surface can be attributed to the increased diffusion of Na ion facilitated by Al2O3 NSs. The coverage and thickness of the Al2O3 NSs significantly affects the cell performance because of an increase in shunt resistance associated with the formation of Na2SeX and phase separation. The passivation effect attributed to the Al2O3 NSs is well studied using the bias‐EQE measurement and J–V characteristics under dark and illuminated conditions. With the optimization of the Al2O3 NSs, the remarkable enhancement in the cell performance occurs, exhibiting a power conversion efficiency increase from 2.83% to 5.33%, demonstrating a promising method for improving ultrathin Cu(In,Ga)Se2 devices, and providing significant opportunities for further applications. [ABSTRACT FROM AUTHOR]