Nanotechnology最新文献

Self-powered ultraviolet (UV) photodetectors are widely applicable in various fields due to their ability to operate autonomously, offering unparalleled portability and flexibility. In this letter, a high-performance self-powered UV photodetector based on MAPbCl₃/GaN nn heterojunction is demonstrated. The n-MAPbCl₃microplates were grownin situon the n-GaN substrate using a simple solution process. Thanks to the differences in the energy band between MAPbCl₃and GaN, a built-in electric field is formed, which facilitates efficient separation of photo-generated charge carriers. This enables the photodetector to operate without the need of an external bias voltage. Furthermore, the wide bandgap of both MAPbCl₃and GaN endows the photodetector with exceptional sensitivity to UV light. The optimized MAPbCl₃/GaN device exhibits high-performance metrics, including low dark current and noise, high photo to dark current ratio, responsivity, and detectivity at zero bias.

Amylases are essential enzymatic macromolecules widely employed in industrial sectors such as starch processing, textiles, detergents, paper manufacturing, pharmaceuticals, and biomedical research. Among α-, β-, and γ-amylases, thermostable α-amylases from thermophilic microbes show high catalytic activity and structural stability under heat, pH variation, and solvent stress. These properties make them valuable for stable, contamination-resistant, and efficient bioprocesses. Thermostable amylases also hold promise in biomedical fields, including diagnostics, enzyme replacement therapy, and nanocarrier-based drug delivery. This review summarizes microbial sources and production approaches for thermostable amylases, highlighting submerged and solid-state fermentation methods. The discussion also outlines optimization of carbon and nitrogen substrates, fermentation duration, and moisture control strategies that directly influence enzyme yield and activity. Factors governing enzyme yield and stability are analyzed, including nutrient balance, pH, temperature, and moisture. Despite their potential, widespread application remains limited by low native production yields, suboptimal heterologous expression, and functional trade-offs between thermostability and enzymatic activity. Recent advances in protein engineering (rational design and directed evolution), omics-driven strain improvement, and nanotechnology integration provide paths to address these limitations. By integrating these strategies, researchers are achieving enzymes with longer operational lifetimes, higher substrate specificity, and improved reusability under industrial and physiological conditions. These advances highlight the growing relevance of thermostable amylases in industrial biotechnology and biomedical research.

Glycerol, one of the important bio-platform molecules, is produced in large quantities as a byproduct in the biodiesel industry. It is imperative to convert glycerol into more value-added products (such as dihydroxyacetone, glyceraldehyde, glyceric acid, tartronic acid (TA), mesoxalic acid, glycolic acid, and formic acid) through various methods. Currently, the glycerol electrocatalytic oxidation reaction (GEOR) is one of the most promising routes owing to the mild operating conditions, efficient conversion, and high energy utilizations via coupling the cathodic reaction. In this review, we systematically introduce the recent advances in GEOR for the application of various products synthesis, focusing on the influence of reaction conditions, types of catalysts, and involved oxidation pathway and mechanisms. Furthermore, novelty coupled systems of GEOR and other cathodic reactions are summarized. Lastly, the subsistent challenges and perspectives are highlighted for GEOR.

The development of efficient heterojunction photocatalysts for environmental remediation remains challenging due to rapid charge recombination and insufficient active sites in conventional single-component systems. This study developed a facile wet impregnation method of In₂O₃-Bi₂O₃heterojunction photocatalysts with tunable compositions for enhanced visible-light-driven photocatalytic degradation. By systematically modulating the In₂O₃to Bi₂O₃ratio, the optical properties, electronic structures, and photocatalytic activities of the materials can be precisely manipulated. The optimized 30% In₂O₃-Bi₂O₃heterojunction exhibited a remarkable methylene blue degradation efficiency of 93% under visible light, outperforming pure In₂O₃and Bi₂O₃. Mechanistic studies revealed that the type-II band alignment facilitated spatial separation of photogenerated electron-hole pairs and enhanced redox capacity. Furthermore, the surface oxygen vacancies of materials introduced by the alkaline etching method were found to significantly enhance the availability of active sites and optimize the band structure, contributing to a notable increase in photocatalytic activity. These heterojunctions also exhibited remarkable stability, retaining over 90% degradation efficiency after five consecutive cycles. This study indicates the significant potential of In₂O₃-Bi₂O₃heterojunctions for enhancing environmental remediation and solar energy conversion initiatives, and also introduces a straightforward and effective synthesis approach to photocatalyst design by composition regulation and defect engineering.

Single-walled carbon nanotubes (SWNTs) are promising materials for next-generation electronics, but their application is limited by the coexistence of semiconducting (s-SWNTs) and metallic (m-SWNTs) species produced during synthesis. Here, we systematically optimized the separation of s-SWNTs using the conjugated polymer poly (9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFDD) by varying polymer concentration and decoupling the effects of sonication time and temperature: we evaluated temperature dependence at fixed sonication times (1, 2, and 3 h) and time dependence at fixed temperatures (25 °C, 35 °C, and 45 °C). Increasing PFDD concentration enhanced yield but reduced purity due to non-selective interactions with m-SWNTs. Excessive sonication (e.g. 45 °C for 3 h) further degraded selectivity, while extending sonication beyond 1 h offered little additional yield and shortened nanotube length. The optimal conditions-PFDD 1 mg ml^-1and sonication at 45 °C for 1 h-balanced yield, purity, and length. Field-effect transistors fabricated with s-SWNTs separated under these conditions showed a low off-current (∼10^-11A), a high ON/OFF ratio of 10⁶, and a mobility of 2.2 cm²V^-1s^-1, confirming the effectiveness of this systematic optimization for high-performance electronic devices.

Oblique light emissions are reflected from the interface owing to the total internal reflection. It is found that a waveguide can be used to effectively collect the oblique light emissions of aligned organic dipoles because of the formation of a local quasi-mode evanescent wave. The numerical results show that the highest coupling efficiency and 3 dB spatial deviation of transverse magnetic (transverse electric) wave are 74.3% (78.9%) and 4.1μm (5.2μm), respectively. The proposed structure can be used in an organic light-emitting device for the applications of silicon photonic integrated circuits.

With the growing demand for clean energy technologies, the development of highly efficient hydrogen evolution reaction (HER) electrocatalysts has become increasingly critical for advancing renewable energy systems. In this work, a heterostructure catalyst was fabricated by constructing an interface between a Ni/C-doped nanofilm and monolayer Ti₃C₂T_xusing a magnetron sputtering technique. In 1 M KOH, the optimized catalyst with a Ni/C doping ratio of 1:1 exhibited excellent catalytic performance and long-term stability, delivering a low overpotential of 111 mV at a current density of 10 mA cm^-2. The catalyst maintained its high activity after a 24 h stability test. The enhanced HER activity can be ascribed to the formation of the heterointerface, which promotes efficient adsorption of H⁺and desorption of H₂, along with the synergistic interaction between Ni and C species. This study presents a rational strategy for constructing high-performance, durable, and cost-effective HER electrocatalysts based on Ti₃C₂T_x@NiC heterostructures.

In this paper, we propose a new gas nanosensor based on a dual-gate Schottky barrier carbon nanotube field-effect transistor (DG SB-CNTFET) endowed with an all-terminal gas-sensitive configuration, investigated through full quantum-mechanical simulations. The numerical modeling is performed using the non-equilibrium green's function formalism combined with a pz-orbital nearest-neighbor tight-binding approach to describe quantum transport in SB CNTFETs. Full three-dimensional (3D) electrostatics is incorporated by self-consistently solving the Poisson equation. The sensing principle relies on gas-induced variations in the metal work function at all terminals. The 3D quantum simulation study covers transfer characteristics, potential profiles, charge density distributions, transmission coefficients, and sensitivity in both current-mode and pseudo-threshold voltage-shift mode. Four device configurations are investigated: (i) only the source terminal is sensitive, (ii) both source and drain are sensitive, (iii) source, drain, and top-gate are sensitive, and (iv) all terminals, including the back-control gate, are sensitive. The potential for sensitivity enhancement through coupling capacitance engineering is also examined. Results show that the all-terminal gas-sensitive configuration yields a substantial improvement in the constant-current gate voltage shift, enabling the detection of extremely low gas pressures. These findings establish the proposed DG SB-CNTFET-based nanosensor as a strong candidate for next-generation ultra-sensitive gas detection systems, where compact size, low power consumption, and exceptional sensitivity are critical requirements.

Metalorganic chemical vapor deposition (MOCVD) is a promising synthesis technique for two-dimensional materials such as MoS₂. In this study, we controlled the growth mode of MoS₂on SiO₂using Mo(CO)₆and di-tert-butyl sulfide (DTBS) as precursors by adjusting the process conditions. The growth was directed from amorphous deposition at 400 and 500 °C, to crystalline MoS₂at 600 °C and higher. From 750 °C, not only MoS₂grains were deposited, but Mo metal nuclei were also formed during the process. An enhancement of the grain size was achieved by increasing the S/Mo precursor ratio. A more effective method to enlarge the grains and to lower the number density of crystals was to anneal the SiO₂substrate in Ar atmosphere prior to deposition. The reduced number density suggested that the pretreatment increased the diffusion length of Mo adatom species on the surface. Furthermore, addition of H₂to the N₂carrier gas had two effects on the growth mode, without altering the amount of deposited Mo. On one hand, due to a higher fraction of H₂in the carrier gas, the grain size slightly increased, and on the other hand, a change towards Mo metal deposition was observed. Control of the process conditions offers the opportunity to deposit large MoS₂grains without co-depositing Mo metal.

Carbon nanotubes (CNTs) have gained considerable attention in drug delivery applications due to their high surface area and exceptional electronic and mechanical properties. Doping CNTs with metals like aluminum (Al) and gallium (Ga) can modify their electronic, chemical, and stability characteristics, enhancing their suitability for drug delivery. This study investigates the interaction of the drug molecule 5-fluorouracil (5-FU) with pristine and doped (8,8) CNTs using density functional theory (DFT) calculations with the B3LYP functional and the 6-31 G basis set. The results reveal significant changes in the electronic properties after doping. Aluminum doping increases the energy gap, reducing system reactivity, while gallium doping decreases the energy gap, promoting stronger interactions with the drug. Aluminum doping improves the structural stability of CNTs with 5-FU, whereas gallium enhances the chemical potential and hardness, favoring interactions with the drug molecule. In conclusion, aluminum- and gallium-doped CNTs exhibit different behaviors in drug interactions, allowing for optimization of targeted drug delivery systems. Based on energy gap, chemical potential, and chemical hardness values, both doping types can enhance drug delivery properties, with the specific doping choice dependent on the therapeutic application.