Abstract Single-walled carbon nanotubes (SWCNTs) are promising candidates for next-generation nanoelectronics, but their atomically thin geometry and large surface area make device performance highly susceptible to environmental degradation. Here, we fabricate field-effect transistors based on individual one-dimensional (1D) van der Waals heterostructures consisting of SWCNTs encapsulated by few-layer boron nitride nanotubes (BNNTs). We directly fabricate devices on the same individual nanotube with and without BNNT protection, enabling a reliable comparison of their device performances. Statistical analysis reveals that metallic SWCNTs exhibit enhanced output currents due to the excellent electrostatic screening of BNNTs, whereas semiconducting SWCNTs show reduced hysteresis through environmental isolation. Importantly, BNNTs act as a protective barrier against harsh environments, e.g., oxygen plasma etching, demonstrating their ability and potential to protect the channel during fabrication. This work suggests that coating SWCNTs with atomically smooth BNNT and forming a 1D vdW heterostructure could significantly enhance the electrical performance and environmental robustness.
Abstract Chiral surface ligands can impart optical activity to all-inorganic perovskite nanocrystals, but how this affects chiroptical properties of their assemblies remains unclear. Here we show that self-assembly of CsPbBr3 nanocubes synthesized with a small amount of added chiral ligand N-benzylcinchonidinium bromide (BCD-Br) results in measurable circularly polarized luminescence (CPL). BCD-Br-treated nanocrystals show weak circular dichroism but no detectable CPL in colloidal dispersion. Upon assembly into CsPbBr3 and mixed halide superlattices, they exhibit CPL with a luminescence dissymmetry factor, glum, of (5 ± 2) × 10–3, whereas untreated controls remain near the noise level. Polarization-resolved transient absorption (TA) reveals an extended spin lifetime of hundreds of picoseconds in BCD-Br-treated nanocrystals, while linear-response time-dependent density functional theory (LR-TDDFT) calculations suggest that inter-nanocrystal coupling can enhance the chiroptical response. These results support the idea that ordered nanocrystal assembly can convert weak ligand-induced chirality into an emergent chiroptical response in perovskite nanocrystal solids.
Abstract Alloy nanoparticles (nanoalloys) exhibit tunable physicochemical properties that depend sensitively on atomic arrangement. While most theoretical studies consider nanoalloys in a vacuum, practical systems are typically supported, where strong cluster–substrate interactions can introduce significant lattice strain. Here, we investigate strain as a control parameter for chemical ordering in bimetallic nanoalloys using atomistic simulations. Imposing controlled strain through an implicit anchored interface, we probe the response of NiPt nanoparticles with distinct structural motifs. For truncated-octahedral particles, chemical ordering remains remarkably robust even under large strains, indicating that intrinsic thermodynamic preferences dominate. Conversely, icosahedral nanoparticles exhibit pronounced strain-induced chemical redistribution with a significant increase in surface Ni concentration under tensile strain, attributed to the combined effects of intrinsic geometric frustration and a high fraction of undercoordinated sites. Our results demonstrate that strain can selectively modulate chemical ordering in a structure-dependent manner, establishing a general framework for understanding strain-induced chemical ordering in nanoalloys.
Abstract Anatase TiO2 derived rock-salt NaTiO2 has emerged as a superior anode material for efficient sodium ion storage, but the dynamic structural evolution mechanism has yet been fully revealed. Herein, based on comprehensive electrochemical analyses and in situ structural characterizations, an overall structural evolution mechanism is established. Specifically, upon repeated sodiation and desodiation, considerable sodium ions are irreversibly intercalated into the anatase TiO2, straightening initially distorted TiO6 octahedra and producing a cubic rock-salt NaTiO2. Notably, the in situ formed rock-salt NaTiO2 delivers an ultrahigh specific capacity of 256 mA h g–1 at 0.1 A g–1 and maintains a high value of 165 mA h g–1 even at 10 A g–1. When coupled with a graphene-based capacitive cathode, the as-built sodium-ion capacitor achieves a high energy density of 102 W h kg–1, a high power density of 6.8 kW kg–1, and a prolonged cycling stability of 40 000 cycles, achieving collaborative improvements in comprehensive performances.
Abstract Characterizing metal solubilities in post-transition-based liquid metals remains challenging due to their inherent opacity to conventional light-based analytical techniques. In this work, we present an in situ heating methodology within a transmission electron microscope that enables direct probing of the behavior of solid metal solutes within the local boundaries of liquid metal nanodroplets. Specifically, we show that the solubility of transition and precious metals in liquid state metallic solvents is dependent on the droplet size that contains them due to the internal Laplace pressure. We also show that the dissolution behaviors of solute metals in gallium–indium and gallium–indium–tin eutectic nanodroplets deviate from that of pure gallium, with solvent composition influencing solubility. Moreover, entropy-driven solubility effects are studied in multicomponent alloys that contain several solutes. The outcomes of this work are crucial for advancing liquid metal-based functionalities of soft systems, particularly for catalysis.
