Nanoscale Horizons最新文献

MoS₂ and related transition metal dichalcogenides (TMDs) have recently been reported as having extensive applications in nanoelectronics and catalysis because of their unique physical and chemical properties. However, one practical challenge for MoS₂-based applications arises from the easiness of oxygen contamination, which is likely to degrade performance. To this end, understanding the states and related energetics of adsorbed oxygen is critical. Herein, we identify various states of oxygen species adsorbed on the MoS₂ surface with first-principles calculations. We reveal a "dissociative" mechanism through which a physisorbed oxygen molecule trapped at a sulfur vacancy can split into two chemisorbed oxygen atoms, namely a top-anchoring oxygen and a substituting oxygen, both of which show no adsorbate induced states in the bandgap. The electron and hole masses show an asymmetric effect in response to oxygen species with the hole mass being more sensitive to oxygen content due to a strong hybridization of oxygen states in the valence band edge of MoS₂. Alteration of oxygen content allows modulation of the work function up to 0.5 eV, enabling reduced Schottky barriers in MoS₂/metal contact. These results show that oxygen doping on MoS₂ is a promising method for sulfur vacancy healing, carrier mass controlling, contact resistance reduction, and anchoring of surface electron dopants. Our study suggests that tuning the chemical composition of oxygen is viable for modulating the electronic properties of MoS₂ and likely other chalcogen-incorporated TMDs, which offers promise for new optoelectronic applications.

The unique features of metal-organic frameworks (MOFs) such as biodegradability, reduced toxicity and high surface area offer the possibility of developing smart nanosystems for biomedical applications through the simultaneous functionalization of their structure with biologically relevant ligands and the loading of biologically active cargos, ranging from small drugs to large biomacromolecules, into their pores. Aiming to develop efficient, naturally inspired biocompatible systems, recent research has combined organic and materials chemistry to design innovative composites that exploit carbohydrate chemistry for the functionalization and structural modification of MOFs. Scientific investigation in the field has seen a significant rise in the past five years, and it is becoming crucial to acknowledge both the limits and benefits of this approach for future investigation. In this review, the latest research results merging carbohydrates and MOFs are discussed, with a particular emphasis on the advances in the field and the remaining challenges, including addressing sustainability and real-case applicability.

The development and understanding of alternative plasmonic materials are crucial steps for leveraging new plasmonic technologies. Although gold and silver nanostructures have been intensively studied, the promising plasmonic, chemical and physical attributes of rhodium remain poorly investigated. Here, we report the synthesis and plasmonic response of spherical Rh nanoparticles (NPs) with sizes in the 20-40 nm range. Due to the high cohesive energy of this metal, synthesis and experimental investigations of Rh nanospheres in this size range have not been reported; yet, it becomes possible here using a green and one-step laser ablation in liquid method. The localized surface plasmon (LSP) of Rh NPs falls in the ultraviolet spectral range (195-255 nm), but the absorption tail in the visible region increases significantly upon clustering of the nanospheres. The surface binding ability of Rh NPs towards thiolated molecules is equivalent to that of Au and Ag NPs, while their chemical and physical stability at high temperatures and in the presence of strong acids such as aqua regia is superior to those of Au and Ag NPs. The plasmonic features are well described by classical electrodynamics, and the results are comparable to Au and Ag NPs in terms of extinction cross-section and local field enhancement, although blue shifted. This allowed, for instance, their use as an optical nanosensor for the detection of ions of toxic metals in aqueous solution and for the surface enhanced Raman scattering of various compounds under blue light excitation. This study explores the prospects of Rh NPs in the realms of UV and visible plasmonics, while also envisaging a multitude of opportunities for other underexplored applications related to plasmon-enhanced catalysis and chiroplasmonics.

Initially observed on synthetic nanoparticles, the existence of biomolecular corona and its role in determining nanoparticle identity and function are now beginning to be acknowledged in biogenic nanoparticles, particularly in extracellular vesicles - membrane-enclosed nanoparticle shuttling proteins, nucleic acids, and metabolites which are released by cells for physiological and pathological communication - we developed a methodology based on fluorescence correlation spectroscopy to track biomolecular corona formation on extracellular vesicles derived from human red blood cells and amniotic membrane mesenchymal stromal cells when these vesicles are dispersed in human plasma. The methodology allows for tracking corona dynamics in situ under physiological conditions. Results evidence that the two extracellular vesicle populations feature distinct corona dynamics. These findings indicate that the dynamics of the biomolecular corona may ultimately be linked to the cellular origin of the extracellular vesicles, revealing an additional level of heterogeneity, and possibly of bionanoscale identity, that characterizes circulating extracellular vesicles.

M-N₄-C single-atom catalysts (MN₄) have gained attention for their efficient use at the atomic level and adjustable properties in electrocatalytic reactions like the ORR, OER, and HER. Yet, understanding MN₄'s activity origin and enhancing its performance remains challenging. Edge-doped substituents profoundly affect MN₄'s activity, explored in this study by investigating their interaction with MN₄ metal centers in ORR/OER/HER catalysis (Sub@MN₄, Sub = B, N, O, S, CH₃, NO₂, NH₂, OCH₃, SO₄; M = Fe, Co, Ni, Cu). The results show overpotential variations (0 V to 1.82 V) based on Sub and metal centers. S and SO₄ groups optimize FeN₄ for peak ORR activity (overpotential at 0.48 V) and reduce OER overpotentials for NiN₄ (0.48 V and 0.44 V). N significantly reduces FeN₄'s HER overpotential (0.09 V). Correlation analysis highlights the metal center's key role, with ΔG_*H and ΔG_*OOH showing mutual predictability (R² = 0.92). E_g proves a reliable predictor for Sub@CoN₄ (ΔG_*OOH/ΔG_*H, R² = 0.96 and 0.72). Machine learning with the KNN model aids catalyst performance prediction (R² = 0.955 and 0.943 for ΔG_*OOH/ΔG_*H), emphasizing M-O/M-H and the d band center as crucial factors. This study elucidates edge-doped substituents' pivotal role in MN₄ activity modulation, offering insights for electrocatalyst design and optimization.

Our Emerging Investigator Series features exceptional work by early-career nanoscience and nanotechnology researchers. Read Mohammad Malakooti's Emerging Investigator Series article 'Green synthesis of iron-doped graphene quantum dots: an efficient nanozyme for glucose sensing' (https://doi.org/10.1039/D4NH00024B) and read more about him in the interview below.

The advent of the novel in-sensor/near-sensor computing paradigm significantly eliminates the need for frequent data transfer between sensory terminals and processing units by integrating sensing and computing functions into a single device. This approach surpasses the traditional configuration of separate sensing and processing units, thereby greatly simplifying system complexity. Two-dimensional materials (2DMs) show immense promise for implementing in-sensor computing systems owing to their exceptional material properties and the flexibility they offer in designing innovative device architectures with heterostructures. This review highlights recent progress and advancements in 2DM-based in-sensor computing research, summarizing the unique physical mechanisms that can be leveraged in 2DM-based devices to achieve sensory responses and the essential biomimetic synaptic characteristics for computing functions. Additionally, the potential applications of 2DM-based in-sensor computing systems are discussed and categorized. This review concludes with a perspective on future development directions for 2DM-based in-sensor computing.

Nanoparticle interactions with biological systems are intricate processes influenced by various factors, among which the formation of protein corona plays a pivotal role. This research investigates a novel aspect of nanoprotein corona-cell interactions, focusing on the impact of the protein corona on the recovery of disrupted tight junctions in endothelial cells. We demonstrate that the protein corona formed on the surface of star-shaped nanoparticles induces the aggregates of ZO-1, which is quite important for the barriers' integrity. Our research emphasizes that the APOA1 pre-coating on the nanoparticles reduces the ZO-1 expression of endothelial cells offering a promising strategy for overcoming the bio barriers. These findings contribute to our understanding of the interplay between nanoparticles, protein corona, and endothelial cell junctions, offering insights for developing innovative therapeutic approaches targeting the blood-brain barrier integrity. Our study holds promise for the future of nanomedicine, nano drug delivery systems and development of strategies to mitigate potential adverse effects.

In inorganic crystals, phonons are the elementary excitations describing the collective atomic motions. The study of phonons plays an important role in terms of understanding thermal transport behavior and acoustic properties, as well as exploring the interactions between phonons and other energy carriers in materials. Thus, efficient and accurate prediction of phonon transport properties such as thermal conductivity is crucial for revealing, designing, and regulating material properties to meet practical requirements. In this paper, typical strategies used to predict phonon transport properties in modern science and technologies are introduced, and relevant achievements are emphasized. Moreover, insights into the remaining challenges as well as future directions of phonon transport-related exploration are proposed. The viewpoints of this paper are expected to provide a valuable reference to the community and inspire relevant research studies on predicting phonon transport properties in the near future.

The importance of hardware security increases significantly to protect the vast amounts of private data stored on edge devices. Physical unclonable functions (PUFs) are gaining prominence as hardware security primitives due to their ability to generate true random digital keys by exploiting the inherent randomness of the physical devices. Traditional approaches, however, require significant data movement between memory units and PUF generation circuits to perform encryption, presenting considerable energy efficiency and security challenges. This study introduces an innovative approach where PUF key generation and encryption are accomplished in the same vertically integrated resistive random access memory (V-RRAM), alleviating the data movement issue. The proposed V-RRAM encryption machine offers concealable PUFs, high area efficiency, and multi-thread data handling using parallel XOR logic operations. The encryption machine is compared with other machines, demonstrating the highest spatiotemporal cost-effectiveness.