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Photolithography is a key process in the fabrication of carbon nanotube devices. However, the strong interactions between organic photoresists and single-wall carbon nanotube (SWCNT) films result in residual photoresists on their surfaces after lithography, which increases the interfacial resistance between the SWCNTs and between the SWCNTs and the metallic electrodes. To reduce the contamination of the photoresist in the photolithography process, we introduce an ultrathin aluminum metal protective layer to isolate the photoresist and the SWCNT film in the photolithography process, which is prepared via simple thermal evaporation. The protective layer can be removed by etching with the developer and subsequent acid solution without affecting the patterns, while the SWCNT film maintains a clean surface. The resulting SWCNT thin-film transistors exhibit an order of magnitude greater on-state current and carrier mobility than those without the protective layer because a substantial decrease in the resistance between the SWCNTs and between the SWCNT film and the metallic electrodes. This work provides an important scheme for the fabrication of high-performance carbon-based devices. [ABSTRACT FROM AUTHOR]

Artificial van der Waals (vdWs) heterostructures offer unprecedented opportunities to explore and reveal novel synergistic electronic and optical phenomena, which are beneficial for the development of novel optoelectronic devices at atomic limits. However, due to the damage caused by the device fabrication process, their inherent properties such as carrier mobility are obscured, which hinders the improvement of device performance and the incorporation of vdWs materials into next-generation integrated circuits. Herein, combining pump-probe spectroscopic and scanning probe microscopic techniques, the intrinsic optoelectronic properties of PtSe2/MoSe2 heterojunction were nondestructively and systematically investigated. The heterojunction exhibits a broad-spectrum optical response and maintains ultrafast carrier dynamics (interfacial charge transfer ~ 0.8 ps and carrier lifetime ~ 38.2 ps) simultaneously. The in-plane exciton diffusion coefficient of the heterojunction was extracted (19.4 ± 7.6 cm2·s−1), and its exciton mobility as high as 756.8 cm2·V−1·s−1 was deduced, exceeding the value of its components. This enhancement was attributed to the formation of an n-type Schottky junction between PtSe2 and MoSe2, and its built-in electric field assisted the ultrafast transfer of photogenerated carriers from MoSe2 to PtSe2, enhancing the in-plane exciton diffusion of the heterojunction. Our results demonstrate that PtSe2/MoSe2 is suitable for the development of broad-spectrum and sensitive optoelectronic devices. Meanwhile, the results contribute to a fundamental understanding of the performance of various optoelectronic devices based on such PtSe2 two-dimensional (2D) heterostructures. [ABSTRACT FROM AUTHOR]

The large-scale space structure during on-orbit assembly is a time-varying system. The dynamic modeling problem of such incrementally increasing space structure is investigated, and a modular dynamic modeling approach is proposed in this paper. The dynamic model of each substructure is first established, and then, a database is designed to store substructure models, which is used for subsequent dynamic modeling in the assembly process. The fixed connection relationship between adjacent substructures is described by constraint conditions, which lead to the coefficient matrices of adjacent substructures being decoupled. The substructures are assembled in a given sequence, and then, the dynamic modeling, to describe the large-scale space structure on-orbit assembly, is gradually completed via using the proposed modeling approach. The numerical simulation is finally presented. The results demonstrate that the extra calculation resulting from the coefficient matrices coupling of adjacent substructures is avoided. Moreover, the proposed dynamic model can accurately describe the dynamic characteristics of the large-scale space structure during on-orbit assembly. [ABSTRACT FROM AUTHOR]

Aqueous Zn-ion batteries (AZIBs) are attractive for next-generation renewable and secure energy storage systems due to their high safety and low cost. However, dendrite growth and side reactions of Zn metal anodes severely limit their practical applications. Moreover, polarization is an important but easily overlooked factor hampering the development of AZIBs. Herein, a zincophilic, hydrophilic, and thin (∼100 nm) SnO2 protective layer is reported to remodel the Zn anode/electrolyte interface via a simple spin-coating approach. The SnO2 layer effectively inhibits the growth of the dendrites, which prolongs the lifetime of Zn anodes to 3900 h. It also alleviates the side reactions and endows Zn‖Cu cells with a high Coulombic efficiency of 99.3% over 2000 cycles. Meanwhile, the SnO2 layer presents fast Zn deposition kinetics to ensure reversible Zn anodes at high current/capacity by decreasing electrochemical polarization and concentration polarization. Consequently, SnO2/Zn anodes exhibit a high cumulative capacity of 4.5 A h cm−2 at an ultrahigh current of 30 mA cm−2 with a low overpotential of 90 mV and even 3.2 A h cm−2 at a high capacity of 4 mA h cm−2 and high current of 8 mA cm−2. Prototype SnO2/Zn‖δ-MnO2 full cells also obtain higher capacities and capacity retention (96.9% after 500 cycles at 2C) than bare Zn. This work offers new insights for ensuring the reversibility and durability of Zn anodes with low polarization at high current/capacity and provides a promising way to promote the practical application of AZIBs. [ABSTRACT FROM AUTHOR]

Abstract Electrical transport properties of individual metallic double-walled carbon nanotubes (DWCNTs) were measured down to liquid helium temperature, and multi-stable conductance states were found in DWCNTs. At a certain temperature, DWCNTs can switch continuously between two or more electronic states, but below certain temperature, DWCNTs are stable only at one of them. The temperature for switching is always different from tube to tube, and even different from thermal cycle to cycle for the same tube. In addition to thermal activation, gate voltage scanning can also realize such switching among different electronic states. The multi-stable conductance states in metallic DWCNTs can be attributed to different Fermi level or occasional scattering centers induced by different configurations between their inner and outer tubes.