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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]

Nickel oxide (NiO) nanoparticles are distributed uniformly in the vertically aligned carbon nanotube arrays (VACNTs) with millimeter thickness by an effective supercritical carbon dioxide-assisted method. The as-prepared VACNT/NiO hybrid structures are used as electrodes without binders and conducting additives for supercapacitor applications. Due to the synergetic effects of NiO and VACNTs with nanoporous structures and parallel 1D conductive paths for electrons, the supercapacitors exhibit a high capacitance of 1088.44 F g−1. Furthermore, an asymmetric supercapacitor is assembled using the as-synthesized VACNTs/NiO hybrids as the positive electrode and the VACNTs as the negative electrode. Remarkably, the energy density of the asymmetric supercapacitor is as high as 90.9 Wh kg−1 at 3.2 kW kg−1 and the maximum power density reaches 25.6 kW kg−1 at 24.9 Wh kg−1, which are superior to those of the NiO or VACNTs-based asymmetric supercapacitors. More importantly, the asymmetric supercapacitors exhibit capacitance retention of 87.1% after 2000 cycles at 5 A g−1. The work provides a novel approach in decorating highly dense and long VACNTs with active materials, which are promising electrodes for supercapacitors with ultrahigh power density and energy density. [ABSTRACT FROM AUTHOR]

In this paper, a new cruciform donor-acceptor molecule 2,2'-((5,5'-(3,7-dicyano-2,6-bis(dihexylamino)benzo[1,2-b:4,5-b']difuran-4,8-diyl)bis(thiophene-5,2-diyl))bis (methanylylidene))dimalononitrile ( BDFTM) is reported. The compound exhibits both remarkable solid-state red emission and p-type semiconducting behavior. The dual functions of BDFTM are ascribed to its unique crystal structure, in which there are no intermolecular face-to-face π-π interactions, but the molecules are associated by intermolecular CN...π and H-bonding interactions. Firstly, BDFTM exhibits aggregation-induced emission; that is, in solution, it is almost non-emissive but becomes significantly fluorescent after aggregation. The emission quantum yield and average lifetime are measured to be 0.16 and 2.02 ns, respectively. Crystalline microrods and microplates of BDFTM show typical optical waveguiding behaviors with a rather low optical loss coefficient. Moreover, microplates of BDFTM can function as planar optical microcavities which can confine the emitted photons by the reflection at the crystal edges. Thin films show an air-stable p-type semiconducting property with a hole mobility up to 0.0015 cm2V−1s−1. Notably, an OFET with a thin film of BDFTM is successfully utilized for highly sensitive and selective detection of H2S gas (down to ppb levels). [ABSTRACT FROM AUTHOR]

The synthesis of a new tetrathiafulvalene derivative with an electron-withdrawing benzothiadiazole moiety and its use in thin-film organic field-effect transistors (OFETs) are reported. Compared to reported OFETs with other TTF derivatives, a high hole mobility up to 0.73 cm2 V−1 s−1, low off-current and high on/off ratio up to 105 are demonstrated. In addition, the developed OFETs show fast responsiveness toward chemical vapors of DECP (diethyl chlorophosphate) or POCl3 which are simulants of phosphate-based nerve agents. In contrast to previously reported OFET-based sensors, off-current is used as the output signal, which increases quickly upon exposure to either DECP or POCl3 vapors. High sensitivity is demonstrated toward DECP and POCl3 vapors, with concentrations as low as 10 ppb being detected. These OFETs are also responsive to TNT vapor. The sensing mechanisms for the new type of OFET are discussed. [ABSTRACT FROM AUTHOR]

Recently, the design and development of efficient microwave absorbents by facile engineering approaches have attracted much attention. Particularly, some unique structures caused by cross‐scale design are promising in enhancing the absorbing capability toward microwave irradiation. Herein, the cross‐scale design strategy is implemented to enhance the electromagnetic wave absorption performance of polymetallic sulfides (PMS). In PMS, the dipole polarization unit is optimized, and the distribution of electronic states is improved by doping Ti atoms; Meanwhile, the MS/M3S4 homogeneous hetero‐phases interfaces is constructed in PMS using a phase separation strategy; and the conductivity of PMS is modulated by the addition of acetylene black (ACET). The cross‐scale synergy of microwave absorption leads to a significant enhancement of the microwave absorption (MA) performance of PMS/ACET composites. The optimal reflection loss value of Ti‐LES with 10% ACET addition reaches −55.49 dB and the effective absorption bandwidth reaches 6.73 GHz. The 17.5% ACET‐conditioned Ti‐HES achieves a reflection loss of −37.2 dB at a low frequency of 4.8 GHz. This study not only provides a novel strategy for the development of new broadband MA materials but also validates a new idea for the multi‐scale synergistic optimization of MA materials. [ABSTRACT FROM AUTHOR]

Z. T. Liu, G. X. Zhang, S.‐X. Liu, D. Q. Zhang, and co‐workers report a new cruciform donor–acceptor molecule, BDFTM, exhibiting both remarkable solid‐state red emission and p‐type semiconducting behavior. On page 4250, crystalline microrods and microplates of BDFTM show typical optical waveguiding behaviors with a rather low optical loss co‐efficient. Notably, an organic field‐effect transistor with a thin film of BDFTM is successfully utilized for the highly sensitive and selective detection of H2S gas, down to ppb levels. [ABSTRACT FROM AUTHOR]