Nanotechnology最新文献

Hydrogen generation via photocatalytic water splitting holds significant potential as a strategy to tackle energy crises and environmental degradation. We investigated the electronic and photocatalytic properties of SiP single-walled nanotubes as potential photocatalysts employing HSE06 hybrid density functional along with all-electron Gaussian basis sets. Relative to the monolayer, the band gap of nanotube is reduced (e.g., 1.99 eV for (55,0)), and the nature of electron transfer in nanotube changes to direct which can extend the visible light absorption range. Moreover, the hydrogen production rate for SiP (55,0) nanotube increases from 9.97% to 12.41%. Calculations of the band edge positions under various pH conditions indicate that nanotubes exhibit strong reduction capabilities. Within the pH value between 0 and 7 nanotubes with a radius exceeding 40 Å can split water into H2 and O2 simultaneously under sunlight irradiation. Applying tensile and compressible strain can effectively enhance the oxidation ability for overall water splitting due to downward valance band edge. Furthermore, the difference in mobility between the (50,0) nanotube electrons (140.68 cm2 v-1 s-1) and hole (4.26 cm2 v-1 s-1) suggests that electron-hole recombination can be mitigated. Based on the above findings, we hypothesize that SiP nanotubes should be a potential metal-free photocatalyst.

Nanoparticles and nanomaterials are revolutionizing medicine by offering diverse tools for diagnosis and therapy, including devices, contrast agents, drug delivery systems, adjuvants, therapeutics, and theragnostic agents. Realizing full applied potential requires a deep understanding of the interactions of nano dimensional objects with biological cells. In this study, we investigate interaction of single-crystal diamond nanoneedles (SCDNNs) containing silicon vacancy (SiV-) colour centres with biological substances. Four batches of the diamond needles with sizes ranging between 200 nm to 1300 nm and their water suspensions were used in these studies. The human lung fibroblast cells were used for the proof-of-concept demonstration. Employing micro-photoluminescence (PL) mapping, confocal microscopy, and lactate dehydrogenase (LDH) viability tests, we evaluated the cellular response to the SCDNNs. Intriguingly, our investigation with PL spectroscopy revealed that the cells and SCDNNs can coexist together with approved efficient registration of SiV- centres presence. Notably, LDH release remained minimal in cells exposed to optimally sized SCDNNs, suggesting a small number of lysed cells, and indicating non-cytotoxicity in concentrations of 2 µg/ml to 32 µg/ml. The evidence obtained highlights the potential of SCDNNs for extra- or/and intracellular drug delivery when the surface of the needle is modified. In addition, fluorescent defects in the SCDNNs can be used for bioimaging as well as optical and quantum sensing. .

To implement a neuromorphic computing system capable of efficiently processing vast amounts of unstructured data, a significant number of synapse and neuron devices are needed, resulting in increased area demands. Therefore, we developed a nanoscale vertically structured synapse device that supports high-density integration. To realize this synapse device, the interface effects between the resistive switching layer and the electrode were investigated and utilized. Electrical and physical analyses were conducted to comprehend the operational mechanism of the developed synapse device. The results indicate that oxygen ions from the resistive switching layer were absorbed by the electrode, forming metal-oxygen bonds. TheVOconcentration in the switching layer that can change the total conductance of the device. To assess its potential as a synapse device in the neuromorphic system, the developed device was evaluated through pattern recognition simulation.

The development of energy-efficient neuromorphic hardware using spintronic devices based on antiferromagnetic (AFM) skyrmion motion on nanotracks has gained considerable interest. Owing to their properties such as robustness against external magnetic fields, negligible stray fields, and zero net topological charge, AFM skyrmions follow straight trajectories that prevent their annihilation at nanoscale racetrack edges. This makes the AFM skyrmions a more favorable candidate over the ferromagnetic (FM) skyrmions for future spintronic applications. This work proposes an AFM skyrmion-based neuron device exhibiting the leaky-integrate-fire (LIF) functionality by exploiting either a thermal gradient or alternatively a perpendicular magnetic anisotropy (PMA) gradient in the nanotrack for leaky behavior by moving the skyrmion in the hotter or lower PMA region, respectively to minimize the system energy. Furthermore, it is shown that the AFM skyrmion couples efficiently to the soft FM layer of a magnetic tunnel junction (MTJ) enabling efficient read-out of the skyrmion. The maximum change of 9.2% in tunnel magnetoresistance (TMR) is estimated while detecting the AFM skyrmion. Moreover, the proposed neuron device has an energy dissipation of 4.32 fJ per LIF operation thus, paving the path for developing energy-efficient devices in AFM spintronics for neuromorphic computing.

Two-dimensional transition metal dichalcogenides (2D TMDs) have attracted considerable interest in materials science due to their exceptional electronic and optoelectronic characteristics, such as high carrier mobility and adjustable band gaps. Although extensive studies have been conducted on various TMDs, a significant gap persists in the understanding of synthesis methods and their effects on the practical use of monolayer tungsten disulfide (WS₂) in optoelectronic devices. This gap is crucial, as the effective incorporation of WS₂into commercial applications relies on the establishment of dependable synthesis techniques that guarantee the material's high quality and uniformity. In this review, we provide a detailed examination of the synthesis methods for monolayer WS₂, emphasizing mechanical stripping, atomic layer deposition (ALD), and chemical vapor deposition (CVD). We discuss the benefits of each technique, including the uniform growth achievable with ALD at lower temperatures and the ability of CVD to generate large-area, high-quality monolayer. Furthermore, we review the performance of WS₂in various electronic and optoelectronic applications, such as field-effect transistors, photodetectors, and logic devices. Our review suggest that ongoing improvements in film uniformity, compatibility with current semiconductor processes, and the long-term stability of WS₂-based devices indicate a promising pathway for transitioning 2D WS₂from laboratory settings to practical applications.

Over the past decade, graphene quantum dots have gained an inexhaustible deal of attention due to their unique zero-dimensional and quantum confinement properties, which boosted their wide research implication and reliable applications. As one of the promising zero-dimensional member and rising star of the carbon family, plant leaf-derived graphene quantum dots have attracted significant attention from scholars working in different research fields. Owing to its novel photophysical properties including high photo-stability, plant leaf-derived graphene quantum dots have been increasingly utilized in the fabrication of optoelectronic devices. Their superior biocompatibility finds their use in biotechnology applications, while their fascinating spin and magnetic properties have maximized their utilization in spin-manipulation devices. In order to promote the applications of plant leaf-derived graphene quantum dots in different fields, several studies over the past decade have successfully utilized plant leaf as sustainable precursor and synthesized graphene quantum dots with various sizes using different chemical and physical methods. In this review, we summarize the Neem and Fenugreek leaves based methods of synthesis of plant leaf-derived graphene quantum dots, discussing their surface characteristics and photophysical. We highlight the size and wavelength dependent photoluminescence properties of plant leaf-derived graphene quantum dots towards their applications in optoelectronic devices such as white light-emitting diodes and photodetectors, as well as biotechnology applications such as in vivo imaging of apoptotic cells and spin related devices as magnetic storage medium. Finally, we particularly discuss possible ways of fine tuning the spin properties of plant leaf-derived graphene quantum dot clusters by incorporation with superconducting quantum interference device, followed by utilization of atomic force microscopy and magnetic force microscopy measurements for the construction of future spin-based magnetic storage media and spin manipulation quantum devices so as to provide an outlook on the future spin applications of plant leaf-derived graphene quantum dots.

Environmental, safety, health, and sustainability (ESHS) have become an indispensable issue in the semiconductor industry. The 'Beyond CMOS' chapter of the International Roadmap for Devices and Systems roadmap introduces the concept of 'Green materials', emphasizing their importance for maintaining sustainability in semiconductor manufacturing. We discuss the current trends of emerging architectures and devices in the perspective of 'Green materials'. Additionally, we highlight the significance of benchmarking and standardization in advancing sustainable practices within the semiconductor industries.

Zinc phthalocyanine (ZnPc), a promising second-generation photosensitizer, suffers from decreased quantum yield of singlet oxygen due to poor water solubility and prone-to-aggregation nature in both physiological environment and solid matrix. To address this issue, in this work we reported a simple ligand-assisted reprecipitation method to prepare aggregation-free ZnPc-doped nanoparticles (NPs). Specifically, a short-chain ligand hexylamine was introduced to coordinate with ZnPc during reprecipitation, so that to alleviate ZnPc aggregation in the polymeric nanomatrix. As a consequence, the as-prepared ZnPc-loaded NPs with an optimal loading content of 4 wt.% acquired a high singlet oxygen quantum yield (Φ_Δ) of 0.5, which was comparable to that of ZnPc monomer (Φ_Δ= 0.55). Moreover, 10 wt.% ZnPc-loaded NPs could still retain a singlet oxygen quantum yield of 0.38. Taking advantage of the aggregation-free nano-photosensitizers (NPSs), efficient photodynamic therapy effect was achieved on HeLa cells upon 660 nm photo-irradiation with an ultra-low light dose (1.8 J cm^-2). This study not only presented a high efficient ZnPc-based NPS, but also proposed a new strategy to reduce the aggregation of metal complex in solid matrix through ligand coordination.

The excellent collection ability of the photo-generated holes from the poly-crystalline lead trihalide perovskite thin films to the poly[3-(4-carboxybutyl)thiophene-2,5,-diyl] (P3CT) or poly(3-hexylthiophene) (P3HT) polymer layer has been used to realize the highly efficient solar cells. The electronic and molecular structures of the p-type polymers play the decisive roles in the photovoltaic responses of the resultant perovskite solar cells. It is fundamental to understand the relation between the material properties and the photovoltaic performance in order to achieve the highest power conversion efficiency. We review the molecular packing, morphological, optical, excitonic, and surface properties of the P3CT and P3HT polymer layers in order to correctly understand the working mechanisms of the resultant solar cells, thereby predicting the required material properties of the used p-type polymers as the efficient hole transport layer.

Localized surface plasmon resonance (LSPR) is an optical phenomenon associated with noble metal nanostructures. The resonances result in sharp spectral absorption peaks as well as enhanced local electromagnetic fields, which have been widely used in chemical and biological sensing. Over the past decade, as label-free analytical method, LSPR sensors have gained considerable interest and undergone rapid development. In addition to conventional refractive-index sensing through resonant wavelength shift, molecular sensing by colorimetry and imaging techniques have also been developed. Moreover, the LSPR sensors have been integrated with other techniques such as micro/nano fluidics and artificial intelligence to enhance their functionality and performances. In this work, we provide an overview of the recent advancement in LSPR sensors technology, including refractive-index, colorimetric, and imaging-based sensors., as well as the incorporation of new technologies like artificial intelligence. .