Wafer‐scale fabrication of high‐performance uniform organic electronic materials is of great challenge and has rarely been realized before. Previous large‐scale fabrication methods always lead to ...different layer thickness and thereby poor film and device uniformity. Herein, the first demonstration of 4 in. wafer‐scale, uniform, and high‐performance n‐type polymer monolayer films is reported, enabled by controlling the multi‐level self‐assembly process of conjugated polymers in solution. Since the self‐assembly process happened in solution, the uniform 2D polymer monolayers can be facilely deposited on various substrates, and theoretically without size limitations. Polymer monolayer transistors exhibit high electron mobilities of up to 1.88 cm2 V−1 s−1, which is among the highest in n‐type monolayer organic transistors. This method allows to easily fabricate n‐type conjugated polymers with wafer‐scale, high uniformity, low contact resistance, and excellent transistor performance (better than the traditional spin‐coating method). This work provides an effective strategy to prepare large‐scale and uniform 2D polymer monolayers, which could enable the application of conjugated polymers for wafer‐scale sophisticated electronics.
Using a multi‐level self‐assembly strategy, an n‐type polymer monolayer field‐effect transistor is obtained on wafer‐scale. These devices offers high performance, high air‐stability, and high uniformity. The strategy enhances the formation of wafer‐scale and uniform polymer monolayers. Transistor arrays on a 4 in. wafer exhibit electron mobilities of up to 1.88 cm2 V−1 s−1, among the highest reported until now for n‐type monolayer organic transistors.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Conjugated polymers usually form crystallized and amorphous regions in the solid state simultaneously, making it difficult to accurately determine their precise microstructures. The lack of ...multiscale microstructures of conjugated polymers limits the fundamental understanding of the structure–property relationships in polymer‐based optoelectronic devices. Here, crystals of two typical conjugated polymers based on four‐fluorinated benzodifurandione‐based oligo(p‐phenylene vinylene) (F4BDOPV) and naphthalenediimide (NDI) motifs, respectively, are obtained by a controlled self‐assembly process. The strong diffractivity of the polymer crystals brings an opportunity to determine the crystal structures by combining X‐ray techniques and molecular simulations. The precise polymer packing structures are useful as initial models to evaluate the charge transport properties in the ordered and disordered phases. Compared to the spin‐coated thin films, the highly oriented polymer chains in crystals endow higher mobilities with a lower hopping energy barrier. Microwire crystal transistors of F4BDOPV‐ and NDI‐based polymers exhibit high electron mobilities of up to 5.58 and 2.56 cm2 V−1 s−1, respectively, which are among the highest values in polymer crystals. This work presents a simple method to obtain polymer crystals and their precise microstructures, promoting a deep understanding of molecular packing and charge transport for conjugated polymers.
Conjugated polymer microwire crystals are obtained from solvated aggregates. The precise crystal packing and electronic structure in the polymer microwires are evaluated for understanding of the charge transport properties. Polymer crystal transistors of F4BDOPV‐2T exhibit higher electron mobilities of up to 5.58 cm2 V−1 s−1 with a much lower hopping energy barrier compared with conventional thin‐film transistors.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In pigs, three circovirus species within the genus Circovirus have been identified so far, including the non‐pathogenic Porcine circovirus 1 (PCV1), the pathogenic Porcine circovirus 2 (PCV2) and the ...recently identified Porcine circovirus 3 (PCV3). In April 2019, a new circovirus with a distinct relationship to other circoviruses was identified in several pigs with severe clinical disease in Hunan province, China. The size of the viral genome, tentatively designated as porcine circovirus type 4 (PCV4), is 1,770 nucleotides (nt). PCV4 shows the highest genomic identity to mink circovirus (66.9%) and has identities of 43.2%–51.5% to the other PCV genomes. Two major genes, a replicase (Rep) gene spanning 891 nt and a capsid (Cap) gene spanning 687 nt, were predicted. Furthermore, a TaqMan® real‐time polymerase chain reaction (PCR) targeting the replicase gene was developed to investigate the prevalence of PCV4 in 187 clinical samples from Hunan province, China. The results revealed an overall PCV4 prevalence of 12.8%, with the highest positive rates in nasal swabs (28.5%, 6/21) followed by serum samples (13.4%, 11/82). The clinical significance and pathogenesis of this virus needs further investigation.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
In 2009, a mysterious illness associated with fever, thrombocytopenia, gastrointestinal symptoms, and leucopenia was seen in rural areas in central China, with an initial case fatality rate of 30%. ...After extensive investigation, a novel bunyavirus was identified.
Between late March and mid-July 2009, an emerging infectious disease, which was identified as the severe fever with thrombocytopenia syndrome (SFTS), was reported in rural areas of Hubei and Henan provinces in Central China. The cause of the illness was unknown. The major clinical symptoms included fever, thrombocytopenia, gastrointestinal symptoms, and leukocytopenia, and there was an unusually high initial case fatality rate of 30%. In June 2009, an investigation was performed to identify whether the disease was caused by
Anaplasma phagocytophilum
or other pathogens. Although the clinical symptoms were considered to resemble those of human anaplasmosis,
1
neither bacterial DNA nor . . .
Recycling of spent lithium-ion batteries has recently become a critical issue based on environmental concerns and a desire to reutilize resources. Among the existing recycling strategies, direct ...regeneration is largely encouraged from an economic and environmental perspective. However, current procedures used to separate the active cathode materials from the aluminum foil have some limitations for direct regeneration because they either destroy the structure of the cathode or use too many toxic and expensive reagents. Hence, we conducted comprehensive research on the microstructural evolution of the LiNi
1−
x
−
y
Co
x
Mn
y
O
2
degraded electrode and then proposed a targeted method to recycle the spent cathode materials based on the increased residual lithium compounds. This separation process involves no other reagents but water, and toxic organic solvents, complicated processes, and waste treatments are unnecessary compared with the existing pretreatment strategies. Moreover, the separated cathodes are suitable for direct regeneration. Satisfactory capacity recovery of the cathode was achieved
via
simple sintering. Such a recycling process enables a sustainable closed-loop for the spent cathodes and provides new inspiration for the design of LIB recycling.
Based on the increased residual lithium compounds of the degraded cathode, a green water-based strategy is designed for achieving closed-loop recycling of spent lithium-ion batteries.
Doping of polymeric semiconductors limits the miscibility between polymers and dopants. Although significant efforts have been devoted to enhancing miscibility through chemical modification, the ...electrical conductivities of n‐doped polymeric semiconductors are usually below 10 S cm−1. We report a different approach to overcome the miscibility issue by modulating the solution‐state aggregates of conjugated polymers. We found that the solution‐state aggregates of conjugated polymers not only changed with solvent and temperature but also changed with solution aging time. Modulating the solution‐state polymer aggregates can directly influence their solid‐state microstructures and miscibility with dopants. As a result, both high doping efficiency and high charge‐carrier mobility were simultaneously obtained. The n‐doped electrical conductivity of P(PzDPP‐CT2) can be tuned up to 32.1 S cm−1. This method can also be used to improve the doping efficiency of other polymer systems (e.g. N2200) with different aggregation tendencies and behaviors.
The dynamic behaviors of conjugated polymer aggregates in solution are correlated with the solid‐state doping efficiency of polymer films. The n‐type electrical conductivity of the polymer P(PzDPP‐CT2) can be significantly enhanced by controlling the dynamics of solution‐state aggregates. The method is general and can be used for other polymer systems with different aggregation tendencies and dynamic behaviors.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The role of solution aggregates on the charge transport process of conjugated polymers in electronic devices has gained increasing attention; however, the correlation of the charge carrier mobilities ...between the solution aggregates and the solid‐state films remains elusive. Herein, three polymers, FBDOPV‐2T, FBDOPV‐2F2T, and FBDOPV‐4F2T, are designed and synthesized with distinct aggregation behavior in solution. By combining contact‐free ultrafast terahertz (THz) spectroscopy and field‐effect transistor measurements, we track the charge carrier mobility of the aggregates of these polymers from the solution to the thin‐film state. Remarkably, the mobility of these three polymers is found to follow nearly the same trend (FBDOPV‐2T>FBDOPV‐2F2T≫FBDOPV‐4F2T) in both solutions and thin‐film states. The quantitative mobility correlation indicates that the charge transport properties of solution aggregates play a critical role in determining the thin‐film charge transport properties and final device performance. Our results highlight the importance of investigating and controlling solution aggregation structures towards efficient organic electronic devices.
Different aggregation structures of three BDOPV‐based polymers in solution were obtained via subtle adjustment of the molecular structures. By employing contact‐free ultrafast terahertz (THz) spectroscopy, we directly reveal that the correlation of the charge carrier mobilities between the solution aggregates and the solid‐state films remains highly consistent.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In materials chiral fermions such as Weyl fermions are characterized by nonzero chiral charges, which are singular points of Berry curvature in momentum space. Recently, new types of chiral fermions ...beyond Weyl fermions have been discovered in structurally chiral crystals CoSi, RhSi and PtAl. Here, we have synthesized RhSn single crystals, which have opposite structural chirality to the CoSi crystals we previously studied. Using angle-resolved photoemission spectroscopy, we show that the bulk electronic structures of RhSn are consistent with the band calculations and observe evident surface Fermi arcs and helical surface bands, confirming the existence of chiral fermions in RhSn. It is noteworthy that the helical surface bands of the RhSn and CoSi crystals have opposite handedness, meaning that the chiral fermions are reversed in the crystals of opposite structural chirality. Our discovery establishes a direct connection between chiral fermions in momentum space and chiral lattices in real space.
Abstract
Doping has been widely used to control the charge carrier concentration in organic semiconductors. However, in conjugated polymers, n-doping is often limited by the tradeoff between doping ...efficiency and charge carrier mobilities, since dopants often randomly distribute within polymers, leading to significant structural and energetic disorder. Here, we screen a large number of polymer building block combinations and explore the possibility of designing n-type conjugated polymers with good tolerance to dopant-induced disorder. We show that a carefully designed conjugated polymer with a single dominant planar backbone conformation, high torsional barrier at each dihedral angle, and zigzag backbone curvature is highly dopable and can tolerate dopant-induced disorder. With these features, the designed diketopyrrolopyrrole (DPP)-based polymer can be efficiently n-doped and exhibit high n-type electrical conductivities over 120 S cm
−1
, much higher than the reference polymers with similar chemical structures. This work provides a polymer design concept for highly dopable and highly conductive polymeric semiconductors.
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