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Carbon-based materials/metal hydroxide composite materials are one type of the most promising electrode materials for improving the performance of supercapacitors. They have the advantages of low cost, controllable morphology, high theoretical capacity, and excellent stability. In this study, nickel hydroxide nanosheets were grown vertically on the surface of carbon nanotubes (Ni(OH)2@CNTs) by a wet chemical method at low temperatures. The unique spatial configuration provides a larger specific surface area and exposes more electrochemically active sites, which is more conducive to improving electrochemical performance. The prominent conductivity of carbon nanotubes can quickly transfer electrons and improve the electrochemical cycling stability of the composite. The Ni(OH)2@CNTs composite exhibits excellent electrochemical performance with a specific capacitance of 1234 F g−1 at a current density of 1 A g−1 under a three-electrode system. In addition, an asymmetric supercapacitor (ASC) assembled using Ni(OH)2@CNTs as a cathode material shows an energy density of 65.63 W h kg−1 at a power density of 752.39 W kg−1 and a capacity retention rate of 85.9% after 10 000 cycles at a current density of 2 A g−1. The results indicate that Ni(OH)2@CNTs has prospects for application as a cathode material in high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

With the increasing drilling depth of mines, the cross-complexity of fissures in the rock body, and the frequent occurrence of sudden water surges, polymer slurry, with its advantages of good permeability and strong water plugging, is increasingly used in mine grouting projects. Additional research is needed in order to further improve the grouting performance of polymer slurry, ensure the safety of mining operations, and reduce the grouting cost. In this paper, a polymer composite grouting material was prepared with diphenyl methyl diisocyanate, polyether polyol, and fly ash, as the main raw materials, with coupling agent and catalyst as auxiliary reagents. The performance of the composite grouting material in terms of mechanical properties, thermal stability, hydrophobicity, and bonding was explored. This study's findings indicated that incorporating fly ash led to notable enhancements in the thermal stability and water resistance of the polymer slurry. Furthermore, the introduction of fly ash notably raised the starting degradation temperature of the polymer, boosted the water contact angle of the composite material, and reduced the density and reaction temperature of the composite material. In addition, the catalyst and coupling agent as auxiliary reagents affected the polymers in terms of mechanical properties; in this paper, dibutyltin dilaurate was used as the catalyst, and organosilanes were used as the coupling agent. The catalyst successfully sped up the polymer's gel time, however, an excessive quantity of catalyst compromised the polymer's mechanical characteristics. The addition of organosilanes has a positive effect on the dynamic mechanical properties of the composites, fracture toughness, compression, bending, and bond strength. The research can offer a theoretical direction for creating polymer mixtures in mine grouting projects. [ABSTRACT FROM AUTHOR]

Efficient n-type doping remains a significant challenge in the field of organic thermoelectric materials, despite the documentation of several n-dopants. In this work, a new solution-processable n-type dopant (Py-DMBI) featuring a pyrene unit was synthesized and investigated, with the intention to improve the miscibility of the dopant and naphthalenediimide (NDI)-based conjugated polymer by utilization of the specific interaction between pyrene and the naphthalene diimide units. The results reveal that Py-DMBI shows improved charge-generation efficiency (i.e. the ratio of the number of generated charge carriers to the number of dopant molecules) toward the NDI based conjugated copolymer (PNDI2TEG-2Tz) in comparison with 4-((1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl)dimethyl-amine (N-DMBI), which is a widely used n-dopant. The Py-DMBI doped PNDI2TEG-2Tz exhibits a maximum power factor of 15.7 μW m−1 K−2 with a conductivity and Seebeck coefficient of up to 3.5 S cm−1 and −211 μV K−1, respectively. [ABSTRACT FROM AUTHOR]

Modularized floating solar farms exhibit the potential to replace conventional steel-frame ones, effectively remedying hydroelastic issues of a very large floating structure through discrete modules with mechanical connections. However, the response of the discrete modules under cyclic wave loading has not been fully understood. This paper assesses the motion characteristics and expansibility of modularized floaters in waves, based on computational results from fluid–structural interaction simulations. A crucial factor, denoted as the ratio of frame length to wavelength R = L s / λ , is determined to predict the motions of a large floating solar system in head waves. Results indicate that the motion characteristics is predictable based on the R value. The empirical relationship between the R value and the motion of every unit in an array is analyzed. In particular, the results calculated from using the multiple-rigid-bodies method are also compared with those from using the single-large-hydroelastic-body method, and it was found that these two results are similar when R > 1. This similarity allows for predicting the multi-hinged bodies' behavior in waves through a simplified hydroelastic approach. Overall, this study reports insights that are useful for the design and optimization of modularized solar farms and can help address cyclic loading and motion concerns for long-term durability. [ABSTRACT FROM AUTHOR]

In recent decades, polymer semiconductors, extensively employed as charge transport layers in devices like organic field‐effect transistors (OFETs), have undergone thorough investigation due to their capacity for large‐area solution processing, making them promising for mass production. Research efforts have been twofold: enhancing the charge mobilities of polymer semiconductors and augmenting their mechanical properties to meet the demands of flexible devices. Significant progress has been made in both realms, propelling the practical application of polymer semiconductors in flexible electronics. However, integrating excellent semiconducting and mechanical properties into a single polymer still remains a significant challenge. This review intends to introduce the design strategies and discuss the properties of high‐charge mobility stretchable conjugated polymers. In addition, another key challenge faced in this cutting‐edge field is maintaining stable semiconducting performance during long‐term mechanical deformations. Therefore, this review also discusses the development of healable polymer semiconductors as a promising avenue to improve the lifetime of stretchable device. In conclusion, challenges and outline future research perspectives in this interdisciplinary field are highlighted. [ABSTRACT FROM AUTHOR]

In multi-label learning, the label-specific features learning framework can effectively solve the dimensional catastrophe problem brought by high-dimensional data. The classification performance and robustness of the model are effectively improved. Most existing label-specific features learning utilizes the cosine similarity method to measure label correlation. It is well known that the correlation between labels is asymmetric. However, existing label-specific features learning only considers the private features of labels in classification and does not take into account the common features of labels. Based on this, this paper proposes a Causality-driven Common and Label-specific Features Learning, named CCSF algorithm. Firstly, the causal learning algorithm GSBN is used to calculate the asymmetric correlation between labels. Then, in the optimization, both -norm and -norm are used to select the corresponding features, respectively. Finally, it is compared with six state-of-the-art algorithms on nine datasets. The experimental results prove the effectiveness of the algorithm in this paper. [ABSTRACT FROM AUTHOR]

Highlights: A systematic summary of current research trends in the development of transition metal disulfides (TMDs) electromagnetic wave (EMW) absorption materials. In-depth comparisons on the structures, preparation methods, application merits of VIB- and VB-group TMDs. Structure engineering modulation of TMDs in achieving superior EMW absorption is outlined from the viewpoints of heterostructures, defects, morphologies, and phases. Exclusive insights into the challenges, strategies, and opportunities in the design of EMW absorption materials with outstanding performance are provided. The laminated transition metal disulfides (TMDs), which are well known as typical two-dimensional (2D) semiconductive materials, possess a unique layered structure, leading to their wide-spread applications in various fields, such as catalysis, energy storage, sensing, etc. In recent years, a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption (EMA) has been carried out. Therefore, it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application. In this review, recent advances in the development of electromagnetic wave (EMW) absorbers based on TMDs, ranging from the VIB group to the VB group are summarized. Their compositions, microstructures, electronic properties, and synthesis methods are presented in detail. Particularly, the modulation of structure engineering from the aspects of heterostructures, defects, morphologies and phases are systematically summarized, focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance. Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Isoindigo (IID) is widely used as organic dye and conjugated unit in opto‐electronic materials. Functionalization of IID to increase its structural complexity is demanding for obtaining diversity properties. Herein, we developed a direct C—H/N—H activation method of IIDs via double alkyne annulations and synthesized π‐extended IIDs with two pairs of 5/7 membered rings. The structure of the π‐extended IIDs was characterized and confirmed by 1H NMR, 13C NMR, HRMS and X ray crystal analysis. Their physical properties were characterized by UV‐vis absorption, cyclic voltammetry and thermogravimetric analysis. The absorption coefficient of the annulated products enhanced significantly compared with the non‐annulated analogue. [ABSTRACT FROM AUTHOR]

Non‐benzenoid polycyclic aromatic hydrocarbons (PAHs) have received a lot of attention because of their unique optical, electronic, and magnetic properties, but their synthesis remains challenging. Herein, we report a non‐benzenoid isomer of peri‐tetracene, diazulenorubicene (DAR), with two sets of 5/7/5 membered rings synthesized by a (3+2) annulation reaction. Compared with the precursor containing only 5/7 membered rings, the newly formed five membered rings switch the aromaticity of the original heptagon/pentagon from antiaromatic/aromatic to non‐aromatic/antiaromatic respectively, modify the intermolecular packing modes, and lower the LUMO levels. Notably, compound 2 b (DAR‐TMS) shows p‐type semiconducting properties with a hole mobility up to 1.27 cm2 V−1 s−1. Moreover, further extension to larger non‐benzenoid PAHs with 19 rings was achieved through on‐surface chemistry from the DAR derivative with one alkynyl group. [ABSTRACT FROM AUTHOR]

Non‐benzenoid polycyclic aromatic hydrocarbons (PAHs) have received a lot of attention because of their unique optical, electronic, and magnetic properties, but their synthesis remains challenging. Herein, we report a non‐benzenoid isomer of peri‐tetracene, diazulenorubicene (DAR), with two sets of 5/7/5 membered rings synthesized by a (3+2) annulation reaction. Compared with the precursor containing only 5/7 membered rings, the newly formed five membered rings switch the aromaticity of the original heptagon/pentagon from antiaromatic/aromatic to non‐aromatic/antiaromatic respectively, modify the intermolecular packing modes, and lower the LUMO levels. Notably, compound 2 b (DAR‐TMS) shows p‐type semiconducting properties with a hole mobility up to 1.27 cm2 V−1 s−1. Moreover, further extension to larger non‐benzenoid PAHs with 19 rings was achieved through on‐surface chemistry from the DAR derivative with one alkynyl group. [ABSTRACT FROM AUTHOR]

Hinged arrays have garnered increasing interest due to their potential to provide flexible and adaptable solutions for the various challenges faced in ocean development. The effectiveness of these arrays in engineering applications heavily depends on the motion characteristics of each individual module, rather than specific modules, such as the one with the strongest motion. However, the presence of hinge constraints results in coupled motion responses of all modules instead of independent ones. The objective of this study is to investigate the motion behavior of large arrays formed by multiple floaters hinged together, while existing literature mainly focused on two-body hinged systems. Based on the potential flow theory and Rankine source panel method, a numerical program was developed to calculate the hydrodynamic interactions and the coupled motion responses. First, a model test was conducted to validate the developed frequency-domain simulations. A good agreement was achieved. Then, the effects of hinge constraints, the number of modules, and two external constraints on the motion responses of the entire array were discussed. The results indicated that the heave motion of the array subjected to hinge constraints was significantly suppressed, but a strong pitch motion occurred in a larger wavelength range. For hinged arrays, the floaters located at the two ends were most likely to be excited with the strongest motions. Moreover, a shorter hinged array could be used to quantify the trends in the motion of arrays with more floaters. The calculation results also revealed that the motion responses of a hinged array were highly sensitive to the external constraints, e.g., mooring lines. [ABSTRACT FROM AUTHOR]

Since light propagation in water bodies is subject to absorption and scattering effects, underwater images using only conventional intensity cameras will suffer from low brightness, blurred images, and loss of details. In this paper, a deep fusion network is applied to underwater polarization images; that is, the underwater polarization images are fused with intensity images using the deep learning method. To construct a training dataset, we establish an experimental setup to obtain underwater polarization images and perform appropriate transformations to expand the dataset. Next, an end-to-end learning framework based on unsupervised learning and guided by an attention mechanism is constructed for fusing polarization and light intensity images. The loss function and weight parameters are elaborated. The produced dataset is used to train the network under different loss weight parameters, and the fused images are evaluated based on different image evaluation metrics. The results show that the fused underwater images are more detailed. Compared with light intensity images, the information entropy and standard deviation of the proposed method increase by 24.48% and 139%. The image processing results are better than other fusion-based methods. In addition, the improved U-net network structure is used to extract features for image segmentation. The results show that the target segmentation based on the proposed method is feasible under turbid water. The proposed method does not require manual adjustment of weight parameters, has faster operation speed, and has strong robustness and self-adaptability, which is important for research in vision fields, such as ocean detection and underwater target recognition. [ABSTRACT FROM AUTHOR]

Emissive organic semiconductors are highly demanding for organic light‐emitting transistors (OLETs) and electrically pumped organic lasers (EPOLs). However, it remains a great challenge to obtain organic semiconductors with high carrier mobility and high photoluminescence quantum yield simultaneously. Here, a new design strategy is reported for highly emissive ambipolar and even n‐type semiconductors by introducing perfluorophenyl groups into polycyclic aromatic hydrocarbons such as perylene and anthracene. The results reveal that 3,9‐diperfluorophenyl perylene (5FDPP) exhibits the ambipolar semiconducting property with hole and electron mobilities up to 0.12 and 1.89 cm2 V−1 s−1, and a photoluminescence quantum yield of 55%. One of the crystal forms of 5FDPA exhibits blue emission with an emission quantum yield of 52% and simultaneously shows the n‐type semiconducting property with an electron mobility up to 2.65 cm2 V−1 s−1, which is the highest value among the reported organic emissive n‐type semiconductors. Furthermore, crystals of 5FDPP are utilized to fabricate OLETs by using Ag as source–drain electrodes. The electroluminescence is detected in the transporting channels with an external quantum efficiency (EQE) of up to 2.2%, and the current density is up to 145 kA cm−2, which are among the highest values for single‐component OLETs with symmetric electrodes. [ABSTRACT FROM AUTHOR]

Molecular probes which can be modulated, functionalized and used to visualize the processes are highly desirable for understanding and manipulating biological systems. Geometric cis and trans isomers of tetraphenylethene (TPE) emerge as attractive candidates to fulfill these tasks thanks to the unique aggregation‐induced emission properties, tailorable structures, and responsiveness to external stimuli. This minireview focuses on cis and trans isomers of TPE derivatives that are functionalized with molecular recognition units for fluorescence detection, bioimaging and cancer therapy. The effects of molecular geometry on fluorescence property, target binding ability and biological activity are summarized. The feasibility to in vitro and in vivo switch molecular configuration and thus bio‐activity is discussed. Finally, the future development and challenges are discussed in view of TPE‐based stereoisomers for targeted sensing and imaging‐guided modulation of biological processes. [ABSTRACT FROM AUTHOR]

Non‐benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi[7]annulene core. Derivatives of this new non‐benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels–Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6‐triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non‐benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new non‐benzenoid acene can be oxidized or reduced by NOSbF6 or KC8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic. [ABSTRACT FROM AUTHOR]

Non‐benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi[7]annulene core. Derivatives of this new non‐benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels–Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6‐triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non‐benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new non‐benzenoid acene can be oxidized or reduced by NOSbF6 or KC8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic. [ABSTRACT FROM AUTHOR]

Organic room‐temperature phosphorescence (RTP) materials have attracted much attention in recent years due to their potential applications. However, the development of organic RTP emitters with a long lifetime and high quantum yield remains a great challenge owing to the weak molecular spin–orbit coupling and high sensitivity to oxygen. In this paper, a new purely organic RTP emitter, 3,3″,4,4″‐diphenylsulfonetetracarboxylic dianhydride (DPS), is reported which shows an excitingly ultralong lifetime up to 1.08 s and high phosphorescence quantum yield of 8%. When anhydride units in DPS are transformed into imides, the RTP performance in terms of lifetime and quantum yield is decreased. The presence of multiple intermolecular interactions is favorable for the restriction of nonradiative decay and the promotion of spin–orbit coupling, which is further corroborated by theoretical calculations. The studies demonstrate that DPS is a promising structural motif for developing high‐performance organic RTP emitters. [ABSTRACT FROM AUTHOR]

We herein report a phosphoric‐acid‐substituted tetraphenylethene (T‐P) capable of adapting its geometric configuration and biological activity to the microenvironment upon light irradiation for apoptosis modulation. Different from most ultraviolet‐responsive isomerization, T‐P undergoes cis‐trans isomerization under visible light irradiation, which is biocompatible and thus photo‐modulation is possible in living biosystems. By using alkaline phosphatase (ALP) and albumin as dual targets, T‐P isomers display different protein binding selectivity, cancer‐cell internalization efficiency and apoptosis‐inducing ability. The proapoptotic activity was found to be kinetically controlled by the enzymatic reaction with ALP and regulated by co‐existing albumin. Motivated by these findings, two‐way modulation of proapoptotic effect and on‐demand boosting anticancer efficacy were realized in vitro and in vivo using light and endogenous proteins as multiple non‐invasive switching stimuli. [ABSTRACT FROM AUTHOR]

We herein report a phosphoric‐acid‐substituted tetraphenylethene (T‐P) capable of adapting its geometric configuration and biological activity to the microenvironment upon light irradiation for apoptosis modulation. Different from most ultraviolet‐responsive isomerization, T‐P undergoes cis‐trans isomerization under visible light irradiation, which is biocompatible and thus photo‐modulation is possible in living biosystems. By using alkaline phosphatase (ALP) and albumin as dual targets, T‐P isomers display different protein binding selectivity, cancer‐cell internalization efficiency and apoptosis‐inducing ability. The proapoptotic activity was found to be kinetically controlled by the enzymatic reaction with ALP and regulated by co‐existing albumin. Motivated by these findings, two‐way modulation of proapoptotic effect and on‐demand boosting anticancer efficacy were realized in vitro and in vivo using light and endogenous proteins as multiple non‐invasive switching stimuli. [ABSTRACT FROM AUTHOR]

Photoresists are essential for the fabrication of flexible electronics through all-photolithographic processes. Single component semiconducting photoresist exhibits both semiconducting and photo-patterning properties, and as a result, the device fabrication process can be simplified. However, the design of semiconducting polymeric photoresist with ambipolar semiconducting property remains challenging. In this paper, we report a single component semiconducting photoresist (PFDPPF4T-N3) by incorporating azide groups and noncovalent conformation locks into the side alkyl chains and conjugated backbones of a diketopyrrolopyrrole-based conjugated polymer, respectively. The results reveal that PFDPP4FT-N3 exhibits ambipolar semiconducting property with hole and electron mobilities up to 1.12 and 1.17 cm2 V−1 s−1, respectively. Moreover, field effect transistors with the individual photo-patterned thin films of PFDPPF4T-N3 also show ambipolar semiconducting behavior with hole and electron mobilities up to 0.66 and 0.80 cm2 V−1 s−1, respectively. These results offer a simple yet effective design strategy for high-performance single component semiconducting photoresists, which hold great potential for flexible electronics processed by all photolithography. [ABSTRACT FROM AUTHOR]

Herein, single‐molecule conductance studies of TBT1‐TBT6 which entails 1,4‐dithienylbenzene as the backbone and SMe groups as the anchoring units, with the scanning tunneling microscope break junction (STM‐BJ) technique, are reported. The molecular conductance of TBT1 with intramolecular O•••S noncovalent interactions is enhanced by about one order of magnitude in comparison to their analogue TBT2 (which contains alkyl instead of alkoxy chains). By replacing the methoxy groups in TBT1 with extending alkoxy chains in TBT3, TBT4, and TBT5, the molecular backbones become twisted and as a consequence the single‐molecule conductance decreases gradually, showing that the intramolecular O•••S noncovalent interaction is influenced by the structural features of alkoxy chains. More importantly, the single‐molecule conductance of TBT3, TBT4, and TBT5 can be boosted by increasing the electric field applied to the molecular junctions. Remarkably, the conductance of TBT3, TBT4, and TBT5 can be reversibly modulated due to the conformational changes between twisted and planar ones by varying the electric field. These results demonstrate that molecules with intramolecular O•••S noncovalent interactions have the potential for in situ control of the electrical properties of molecular‐scale devices. [ABSTRACT FROM AUTHOR]

Multiple relaxation behaviors are promising for broad frequency band and strong electromagnetic wave (EMW) absorption based on polarization‐controlled electromagnetic (EM) attenuation. However, rational selection of materials and structure manipulation through tunable substitution or phase control are challenging toward optimization of EMW absorption. Herein, bi‐metallic organic frameworks (B‐MOFs) with various morphologies are employed as EMW absorbers. Remarkably, the polar units can be enhanced by introducing Ni‐metal nodes into the Cu‐coordinated MOFs, rendering the B‐MOFs with self‐polarized properties and consecutive multifrequency EMW absorption behaviors. The maximum reflection loss of acetylene black (ACET) filled NiCu‐MOFs can reach –40.54 dB together with a wide bandwidth (<‐10 dB) of 5.87 GHz at a thickness of 2.5 mm. As a counterpart of the Ni/Cu/C derivatives, significantly increased broad band absorption (6.93 GHz) and multifrequency absorbing and polarization characteristics are also maintained in bimetal coexisting carbonized architectures as prepared by calcination of CuNi‐MOFs. This work demonstrates that the performance of effective absorbing frequency band can be enhanced in multi‐metallic organic frameworks‐based architectures, and paves a novel avenue for developing broadband and strong EMW absorbers. [ABSTRACT FROM AUTHOR]

Vigorous development of 5G communication technologies can boost mobile networks yet bring in electromagnetic interferences and safety concerns in utilizing electronic devices. Particularly, 5G network can not only involve a low‐frequency band of n78 (3.3–3.8 GHz) but also cover multi‐frequency bands of n77 (3.3–4.2 GHz) and n79 (4.4–5.0 GHz), displaying multiple electromagnetic radiations. Countless efforts have been devoted to investigating electromagnetic wave (EMW) absorbers with low‐ and multi‐band absorption properties. However, in terms of emerging materials and designs, few reports propose the mechanisms related to those properties. This perspective briefly reviews the impressive achievements of low‐ and multi‐frequency EMW absorbers and analyzes the design strategies that may enable low‐ and multi‐frequency absorption. Furthermore, the cutting‐edge mechanisms of corresponding electromagnetic responses, such as Snoek limit, quarter wavelength, and dielectric‐magnetic synergy effects are elaborated. Thus, this perspective can shed light on the new trends and ongoing challenges for EMW absorbers and further promote their practical application. [ABSTRACT FROM AUTHOR]

Molecular systems that can function as photoresists are essential for the fabrication of flexible electronics through all‐photolithographic processes. Most of the reported molecular systems for photo‐patterning of polymeric semiconductors contain binary or multi‐components. In comparison, single component semiconducting photoresist is advantageous since it will circumvent the optimization of phase separation and ensure the patterned semiconducting thin films to be more uniform. In this paper, a single component semiconducting photoresist (PDPP4T‐N3) by incorporating azide groups into the branching alkyl chains of a diketopyrrolopyrrole‐based conjugated polymer is reported. The results reveal that i) the azide groups make the side chains to be photo‐cross‐linkable; ii) uniform patterns with size as small as 5 µm form under mild UV irradiation (365 nm, 85 mW cm−2) at ambient conditions; iii) such photo‐induced cross‐linking does not affect the inter‐chain packing; iv) benefiting from the single component feature, field‐effect transistors (FETs) with the individual patterned thin films display satisfactorily uniform performances with average charge mobility of 0.61 ± 0.10 cm2 V–1 s–1 and threshold voltage of 3.49 ± 1.43 V. These results offer a simple yet effective design strategy for high‐performance single component semiconducting photoresists, which hold great potentials for flexible electronics processed by all‐photolithography. [ABSTRACT FROM AUTHOR]

A perylene five-membered ring diimide, PDI39, was developed as a new electron-deficient building block for n-type semiconductors. The π-expanded conjugated molecules containing azulenes were synthesized from PDI39. These conjugated molecules show helical geometry and near-infrared absorption up to 810 nm. [ABSTRACT FROM AUTHOR]

The interface between molecules and electrodes has great impact on charge transport of molecular devices. Precisely manipulating the structure and electronic coupling of electrode-molecule interface at a molecular level is very challenging. Here, we develop new molecular junctions based on tetrathiafulvalene (TTF)-fused naphthalene diimide (NDI) molecules which are anchored to gold electrodes through direct TTF-Au contacts formed via Au-S bonding. These contacts enable highly efficient orbital hybridization of gold electrodes and the conducting π-channels, yielding strong electrode-molecule coupling and remarkably high conductivity in the junctions. By further introducing additional thiohexyl (SHe) anchors to the TTF units, we develop molecular wires with multiple binding sites and demonstrate reversibly switchable electrode-molecule contacts and junction conductance through mechanical control. These findings show a superb electrode-molecule interface and provide a new strategy for precisely tunning the conductance of molecular devices towards new functions. Though charge transport in molecular devices depend on the electrode-molecule interface, controlling the interface's contact geometry remains a challenge. Here, the authors report molecular junctions featuring TTF-fused NDI molecules anchored to gold electrodes through direct TTF-Au contacts. [ABSTRACT FROM AUTHOR]

Highlights: Detailed summary of current trends in the advancement of flexible EMI shielding materials. The theoretical shielding mechanisms and the latest concept of "green shielding" index (gs) are outlined. Functional applications of flexible EMI shielding materials are introduced from thermal conductivity, hydrophobicity to transparency, sensing even multiple functions. Exclusive insights in challenges and future design strategies opportunities for flexible EMI shielding materials are provided. With rapid development of 5G communication technologies, electromagnetic interference (EMI) shielding for electronic devices has become an urgent demand in recent years, where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role. Meanwhile, the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications. Hitherto, a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed. In this review, we not only introduce the recent development of flexible EMI shielding materials, but also elaborate the EMI shielding mechanisms and the index for "green EMI shielding" performance. In addition, the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized. Finally, we propose several possible research directions for flexible EMI shielding materials in near future, which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials. [ABSTRACT FROM AUTHOR]

Molecular materials that can absorb and emit light in the near-infrared (NIR) region are attracting more and more attention in many fields. In this paper, we report the synthesis and studies of the photophysical and semiconducting properties of tetrathiafulvalene (TTF)–naphthalene diimide (NDI) fused molecules (NDITTF2, NDI2TTF and NDI2TTF3). The results reveal that all molecules show strong absorptions in the NIR region, and their absorption maxima can reach 1015 nm with molar extinction coefficients (ε) up to 66 900 M−1 cm−1 in the solution state. Moreover, NIR emissions were found for NDITTF2 and NDI2TTF either in solution or in the film state. The emission maxima in the CHCl3 solution locate at 892 nm for NDI2TTF (φ = 1.64%) and 1062 nm for NDITTF2 (φ = 0.21%). Furthermore, the thin film of NDITTF2 was found to show p-type semiconducting properties with a hole mobility up to 0.45 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

Development of pure organic molecular materials with room temperature phosphorescence (RTP) and their applications for white emitters have received significant attentions recently. Herein, a D–π–A molecule (DMACPPY) which can realize white emitting under ambient conditions both in the crystal state and the doped‐film state by combining RTP with two fluorescent emissions is reported. The white emission from the crystalline sample of DMACPPY consists fluorescence from S2 (the second excited singlet state) and S1 (the first excited singlet state) along with RTP from T1 (the first excited triplet state), namely, SST‐type white light. While, the white emission from the poly methyl methacrylate (PMMA) film doped with DMACPPY contains fluorescences from S2 and S1, and RTP from T2 (the second excited triplet state) rather than T1 (STS type). DMACPPY cannot exhibit white spectrum within alternative crystalline state since inferior RTP intensity despite similar ternary emissions. The results demonstrate that the emissive properties for excited states of DMACPPY can be tuned by changing the aggregate state from crystalline to dispersion state in PMMA film. This new RTP emitter fulfills the talent for white emitting and achieves dual‐mode white emissions, invisibly, expands the application range for pure organic and heavy atom‐free RTP materials. [ABSTRACT FROM AUTHOR]

VB‐Group transition metal disulfides (TMDs) are considered excellent materials for electromagnetic wave (EMW) absorption because of their good conductivity and abundant active sites located at their edges and substrates, as compared with VIB‐Group TMDs. Herein, for the first time, EMW absorbers based on VB‐Group NbS2 nanosheets by using a facile one‐step solvothermal method are successfully prepared. The minimum reflection loss (RLmin) can reach up to 43.85 dB with an effective absorption bandwidth of 6.48 GHz (11.52–18.00 GHz). The remarkable EMW absorption performance can also be reflected in the tunable frequency bands (C‐, X‐, and Ku‐bands), which is achieved by adjusting the contents of materials. Furthermore, the influence of the content of 2H‐phase and 1T‐phase in NbS2 on the EMW absorption performance is systematically investigated. The hierarchical hollow‐sphere structure of NbS2 promotes dielectric loss and the multiple reflection and absorption of EMW, and enhances the impedance matching and synergistic attenuation ability. This work demonstrates that the bottleneck of effective absorbing frequency band of single‐component dielectric EMW absorbing materials could be broken through, and paves a novel path towards developing broadband absorbing materials in EMW absorption. [ABSTRACT FROM AUTHOR]

Development of pure organic molecular materials with room temperature phosphorescence (RTP) and their applications for white emitters have received significant attentions recently. Herein, a D–π–A molecule (DMACPPY) which can realize white emitting under ambient conditions both in the crystal state and the doped‐film state by combining RTP with two fluorescent emissions is reported. The white emission from the crystalline sample of DMACPPY consists fluorescence from S2 (the second excited singlet state) and S1 (the first excited singlet state) along with RTP from T1 (the first excited triplet state), namely, SST‐type white light. While, the white emission from the poly methyl methacrylate (PMMA) film doped with DMACPPY contains fluorescences from S2 and S1, and RTP from T2 (the second excited triplet state) rather than T1 (STS type). DMACPPY cannot exhibit white spectrum within alternative crystalline state since inferior RTP intensity despite similar ternary emissions. The results demonstrate that the emissive properties for excited states of DMACPPY can be tuned by changing the aggregate state from crystalline to dispersion state in PMMA film. This new RTP emitter fulfills the talent for white emitting and achieves dual‐mode white emissions, invisibly, expands the application range for pure organic and heavy atom‐free RTP materials. [ABSTRACT FROM AUTHOR]

A diazirine‐based four‐armed cross‐linker (4CNN) with a tetrahedron geometry is presented for efficient patterning of polymeric semiconductors by photo‐induced carbene insertion. After blending of 4CNN with no more than 3 % (w/w), photo‐patterning of p‐, n‐, and ambipolar semiconducting polymers with side alkyl chains was achieved; regular patterns with size as small as 5 μm were prepared with appropriate photomasks after 365 nm irradiation for just 40 s. The interchain packing order and the thin film morphology were nearly unaltered after the cross‐linking and the semiconducting properties of the patterned thin films were mostly retained. A complementary‐like inverter with a gain value of 112 was constructed easily by two steps of photo‐patterning of the p‐type and n‐type semiconducting polymers. The results show that 4CNN is a new generation of cross‐linker for the photo‐patterning of polymeric semiconductors for all‐solution‐processible flexible electronic devices. [ABSTRACT FROM AUTHOR]

A diazirine‐based four‐armed cross‐linker (4CNN) with a tetrahedron geometry is presented for efficient patterning of polymeric semiconductors by photo‐induced carbene insertion. After blending of 4CNN with no more than 3 % (w/w), photo‐patterning of p‐, n‐, and ambipolar semiconducting polymers with side alkyl chains was achieved; regular patterns with size as small as 5 μm were prepared with appropriate photomasks after 365 nm irradiation for just 40 s. The interchain packing order and the thin film morphology were nearly unaltered after the cross‐linking and the semiconducting properties of the patterned thin films were mostly retained. A complementary‐like inverter with a gain value of 112 was constructed easily by two steps of photo‐patterning of the p‐type and n‐type semiconducting polymers. The results show that 4CNN is a new generation of cross‐linker for the photo‐patterning of polymeric semiconductors for all‐solution‐processible flexible electronic devices. [ABSTRACT FROM AUTHOR]

The soft nature has endowed conjugated polymers with promising applications in a wide range of field‐effect transistor (FET) based flexible electronics. With unremitting efforts on revealing the molecular structure–property relationships, numerous novel conjugated polymers with high mobility and excellent mechanical property have been developed in the past decades. Incorporating hydrogen‐bonding (H‐bonding) units into semiconducting polymers is one of the most successful strategies for designing high‐performance semiconducting materials. In this review, we aim to highlight the roles of H‐bonding units in the performances of polymeric FETs from three aspects. These include (i) charge mobility enhancement for semiconducting polymers after incorporation of H‐bonding units into the side chains, (ii) the effects of H‐bonding units on the stretchability of conjugated polymers, and (iii) the improvement of self‐healing properties of conjugated polymers containing dynamic hydrogen bonds due to the H‐bonding units in the side chains or conjugated backbones. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrrole (DPP) as a building block has been intensively investigated for organic semiconductors and light emitting materials. The synthesis of N‐aryl DPPs remains challenging. Herein, we firstly report a new easily handled synthetic method toward N‐aryl DPPs through H‐DPP with diaryliodonium salt in the presence of CuI, which shows broad reaction scope. Sixteen N‐aryl DPPs, including phenyl, furan and thiophene as flanking aromatic groups, were synthesized with yields up to 78 %. These N‐aryl DPPs are fluorescent in both solutions and solid states, with quantum yields up to 96 % and 40 %, respectively. Moreover, we show that the reaction between H‐DPP and diaryliodonium salt can lead to π‐expanded DPPs by using Pd(OAc)2 as catalyst. Nine π‐expanded DPPs were obtained in 27–61 % yields. These π‐expanded DPPs exhibit good semiconducting properties with hole mobility of 0.71 cm2 V−1 s−1, demonstrating that they are useful building blocks for high performance organic semiconductors. [ABSTRACT FROM AUTHOR]

Diketopyrrolopyrrole (DPP) as a building block has been intensively investigated for organic semiconductors and light emitting materials. The synthesis of N‐aryl DPPs remains challenging. Herein, we firstly report a new easily handled synthetic method toward N‐aryl DPPs through H‐DPP with diaryliodonium salt in the presence of CuI, which shows broad reaction scope. Sixteen N‐aryl DPPs, including phenyl, furan and thiophene as flanking aromatic groups, were synthesized with yields up to 78 %. These N‐aryl DPPs are fluorescent in both solutions and solid states, with quantum yields up to 96 % and 40 %, respectively. Moreover, we show that the reaction between H‐DPP and diaryliodonium salt can lead to π‐expanded DPPs by using Pd(OAc)2 as catalyst. Nine π‐expanded DPPs were obtained in 27–61 % yields. These π‐expanded DPPs exhibit good semiconducting properties with hole mobility of 0.71 cm2 V−1 s−1, demonstrating that they are useful building blocks for high performance organic semiconductors. [ABSTRACT FROM AUTHOR]

Organic and organometallic π-conjugated molecules with inherent nonlinear optical (NLO) responses have attracted great interest due to their controllable properties via rational structure modifications. However, most of the state-of-the-art materials such as porphyrins, phthalocyanines, and diacetylenes exhibit NLO responses at visible-light regions. Recently, diketopyrrolopyrrole (DPP) based donor–acceptor (D–A) type π-conjugated copolymers have been found to exhibit NLO responses which can reach up to 1064 nm. However, the design rationality of the structure toward NLO properties is not well understood. Herein, four alternating DPP-based copolymers are constructed by using the electron donors of 2-phenylpyridine for P1, 2-thienylpyridine for P2 and their Pt(II)-incorporated moieties for P1Pt and P2Pt. All copolymers display intense intramolecular charge transfer (ICT) processes, and the ICT absorption can be extended to the near-infrared (NIR) region due to the strong D–A interaction of the π-conjugated backbone. The variation tendency of optical bandgaps estimated from the onset of ICT absorption is P1 (1.60 eV) > P1Pt (1.56 eV) > P2 (1.47 eV) > P2Pt (1.44 eV). Open- and closed-aperture Z-scan experiments disclosed that all copolymers exhibit broadband (532 and 1064 nm) NLO properties due to the synergistic effect of excited state absorption and the ICT process upon excitation of 8 ns as well as 25 ps laser pulses. Pt(II)-incorporation can promote or switch the NLO properties due to the efficient triplet-state absorption introduced by the heavy-atom effect. The improvement of the NLO properties is of the order P1 < P1Pt < P2 < P2Pt, which is consistent with the decreasing trend of the copolymer bandgaps. These results will provide guidelines for the rational design of materials toward broadband NLO responses and advanced applications. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: The development of selenophene‐flanked DPP (SeDPP) based copolymers, especially for the ambipolar ones, lags behind other aromatic group flanked DPP‐based polymers. Herein, we report two new ambipolar SeDPP‐based conjugated polymers. One is the alternating polymer PSeDPPFT with normal SeDPP and 3,4‐difluorothiophene units. The other is PSeFDFT, in which the electron acceptor unit is replaced by a new SeDPP derivative, referred as to half‐fused SeDPP. The more planar structure of half‐fused SeDPP endows the backbone of PSeFDFT with good rigidity and planarity. Both polymers exhibit ambipolar transporting properties in air. The PSeFDFT based field‐effect transistors (FETs) display higher and more balanced ambipolar properties with μhave of 0.27 cm2·V–1·s–1, μeave of 0.18 cm2·V–1·s–1, and μhave/μeave of 1.5 than those of PSeDPPFT (μhave = 0.11 cm2·V–1·s–1, μeave = 0.042 cm2·V–1·s–1, and μh/μe = 2.6). This is attributed to the more planar structure, lower LUMO level, higher HOMO level, and better interchain packing orientations of PSeFDFT by comparing with PSeDPPFT. Therefore, a new molecular design strategy to modulate the hole and electron transporting properties is proposed for conjugated D‐A polymers. [ABSTRACT FROM AUTHOR]