Nano Convergence最新文献

Single emitters in solid state are promising sources of single and entangled photons. To boost their extraction efficiency and tailor their emission properties, they are often incorporated in photonic nanostructures. However, achieving accurate and reproducible placement inside the cavity is challenging but necessary to ensure the highest mode overlap and optimal device performance. For many cavity types —such as photonic crystal cavities or circular Bragg grating cavities — even small displacements lead to a significantly reduced emitter-cavity coupling. For circular Bragg grating cavities, this yields a significant reduction in Purcell effect, a slight reduction in efficiency and it introduces polarization on the emitted photons. Here we show a method to achieve high accuracy and precision for deterministically placed cavities on the example of circular Bragg gratings on randomly distributed semiconductor quantum dots. We introduce periodic alignment markers for improved marker detection accuracy and investigate overall imaging accuracy achieving (9.1 ± 2.5) nm through image correction. Since circular Bragg grating cavities exhibit a strong polarization response when the emitter is displaced, they are ideal devices to probe the cavity placement accuracy far below the diffraction limit. From the measured device polarizations, we derive a total spatial process accuracy of (33.5 ± 9.9) nm based on the raw data, and an accuracy of (15 ± 11) nm after correcting for the system response, resulting in a device yield of 68% for well-placed cavities.

A significant amount of effort has been poured into optimizing the delivery system that is demanded by novel therapeutic modalities. Lipid nanoparticle presents as a solution to transfect cells safely and efficiently with nucleic acid-based therapeutics. Among the components that make up the lipid nanoparticle, ionizable lipids are crucial for the transfection efficiency. Traditionally, the design of ionizable lipids relies on literature search and personal experience. With advancements in computer science, we argue that the use of machine learning can accelerate the design of ionizable lipids systematically. Assuming researchers in lipid nanoparticle synthesis may come from various backgrounds, an entry-level guide is needed to outline and summarize the general workflow of incorporating machine learning for those unfamiliar with it. We hope this can jumpstart the use of machine learning in their projects.

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Real-time monitoring of the surrounding gas environment, including our inhaled and exhaled atmosphere, is a crucial but underdeveloped technology for personalized healthcare. Recent advancements in wearable sensing technologies and AI algorithms promise the realization of more powerful wearable gas sensing systems, such as electronic noses. However, fundamental studies are still ongoing in seeking efficient gas sensing materials, transducing mechanisms, and device structures to meet the basic requirement of wearability and low power operation. Low-dimensional metal chalcogenides have attracted significant attention in building flexible gas sensors with room-temperature operation. Their controllable synthesis and post-synthesis treatment allow precise manipulation of the gas adsorption and charge transfer process. Their high surface-to-volume ratio, abundant active surface sites, and tunable electronic properties enable high sensitivity and selectivity, and fast response/recovery even without thermal activation. This review begins with an overview of three transducing mechanisms, providing a comprehensive understanding of the gas sensing process. Aiming at achieving efficient transducers, different types of low-dimensional metal chalcogenides, especially the 0D quantum dots and 2D nanosheets families, have been discussed regarding their synthesis methods and key material design strategies. State-of-the-art low-dimensional metal chalcogenide gas sensors are analyzed based on their modifications to the gas adsorption energy, charge transfer rate, and other fundamental parameters. Moreover, potential system construction towards smart and wearable gas sensor devices has been described with the integration of diversified sensor arrays, wireless communication technologies, and AI algorithms. Finally, we propose the remaining challenges and outlook for developing low-dimensional metal chalcogenide wearable gas sensing and eventually achieving accurate gas mixture classification and odor recognition.

Due to a pivotal role in the post-transcriptional regulation of genes implicated in numerous diseases, miRNAs serve as promising disease biomarkers and therapeutic targets. We introduce a new oligonucleotide probe termed miRNA-trigger, which selectively downregulates newly assigned target mRNAs by hijacking specific miRNAs. By engineering the miRNA-trigger to suppress the anti-apoptotic BCL-xL gene, we induce apoptosis selectively in breast cancer cells overexpressing specific miRNAs and further validate its therapeutic efficacy in vivo, by significantly reducing the tumor volume of the xenograft mouse upon its tail-vein injection. This approach establishes a new platform for self-modulating oligonucleotide therapy by redirecting disease-associated miRNAs.

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Lanthanide-based inorganic nanomaterials have been widely utilized as luminescent materials for broad-ranging applications in lighting, display, and optoelectronic devices. Among lanthanide elements, divalent europium (Eu²⁺) has recently gained significant attention owing to its excellent photoluminescence (PL) properties, such as a short radiative decay lifetime, narrow PL bandwidth, and wide emission range from ultraviolet to near-infrared. Particularly, colloidal metal halide nanocrystals (MHNCs) offer unique advantages as inorganic hosts for Eu²⁺ owing to their excellent phase purity, chemical and optical stability, and colloidal stability for facile integration via solution processes. In addition, the PL properties of Eu²⁺, originating from the parity-allowed 4f–5d transitions, can be precisely controlled by tuning the phase and compositions of MHNCs. Therefore, an in-depth understanding of the Eu²⁺ PL mechanism and synthesis of phase-pure MHNCs is essential for the advancement of Eu²⁺-based MHNCs as novel emitters. This review summarizes recent developments in Eu²⁺-based colloidal MHNCs and their PL properties. First, the local factors affecting the luminescence properties of Eu²⁺ in inorganic hosts are discussed. Subsequently, recent advances in the synthesis of Eu²⁺-based MHNCs using different host–dopant frameworks, their optical proprieties, and applications are outlined. This comprehensive review provides valuable insights for designing high-performance emitters, particularly for achieving deep-blue emission in light-emitting diodes and high-energy scintillators.

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Integrating carbon nanomaterials into solar energy technologies has emerged as a promising strategy to improve efficiency, scalability, and sustainability. Although graphene has excellent carrier mobility, electrical conductivity, and optical transparency, graphene derivatives such as graphene oxide (GO) and reduced graphene oxide (rGO) suffer from significant structural defects and disruption of the sp²-hybridized carbon lattice caused by oxidative processing, severely limiting their electronic and optoelectronic performances. To address these limitations, minimally oxidized graphene (MOG), which includes non-oxidized graphene flakes (NOGFs) and low-oxidized graphene quantum dots (GQDs), has been developed via a nondestructive approach based on ion or molecular intercalation followed by liquid-phase exfoliation. These materials retain the integrity of a π-conjugated network and offer tunable functionalities and solution processability. NOGFs exhibit high conductivity, broadband light absorption, and thermal stability, making them ideal materials for use in solar cell electrodes, photothermal absorbers, and photocatalytic scaffolds. GQDs with tunable bandgaps and abundant functional groups serve as interfacial modifiers in solar cells and as active sites for photocatalysis. This review summarizes recent advances in MOG, focusing on structure–property–performance relationships and applications in solar energy conversion. A comparative evaluation with conventional GO/rGO-based systems is presented along with future directions toward developing high-efficiency graphene-enabled solar technologies.

A 3D motor neuron (MN) spheroid has been developed to investigate neurodegenerative and neuromuscular junction (NMJ) disease. However, core necrosis and reduced neurogenesis, impairing neural network formation, were observed as the MN spheroid matured. In this study, to enhance neural network formation, a biohybrid MN spheroid composed of neural cells/reduced graphene oxide (rGO)/human umbilical vein endothelial cells (HUVECs) was generated for the first time and applied to 3D biosensing system for MNJ disease. By incorporating rGO and HUVECs at the onset of human neural stem cell (hNSC) culture, rGO and HUVECs were evenly distributed within MN spheroid generated by differentiation of hNSC, which improved oxygen- and nutrient- supply by reduction of core necrosis, and enhanced neurogenesis. The fabricated biohybrid MN spheroid improved neural network formation and electrophysiological signal. This method was also applied to generate biohybrid cerebral organoids from human induced pluripotent stem cells (hiPSCs), emphasizing its versatility for diverse 3D neural models. Then, a 3D NMJ biosensing system was fabricated by positioning the biohybrid MN spheroid with muscle bundles to evaluate its utility in neuromuscular disease modeling. Biohybrid MN spheroids generated from induced pluripotent stem cells of sporadic amyotrophic lateral sclerosis (ALS) patients were used to make NMJ. Reduced contraction of the connected muscle bundle due to ALS could be restored by upon treatment with the bosutinib, ALS drug, demonstrating the potential use for drug screening. The method to generate biohybrid spheroid can be applied to generation of various biohybrid brain organoids, and the proposed 3D NMJ biosensing system can be used to drug screening of diverse neuromuscular diseases.

ZnMgO nanoparticles (ZMO NPs) are widely used as electron transport layers in optoelectronic devices such as light-emitting diodes (LEDs) and photodiodes (PDs) primarily because of their facile synthesis and excellent electron transport properties. However, the surface hydroxyl groups (‒OH) on the ZMO NPs introduce charge traps, inhibit electron transport, and reduce device stability, particularly under ambient humidity and oxygen. Therefore, in this study, an alcohol treatment (AT) method was developed to remove surface ‒OH via proton transfer to effectively reduce trap states and dipole moments and enhance surface passivation. Quantum-dot-based LEDs and PDs fabricated using the AT-based ZMO NPs exhibited improved current density, luminance, and external quantum efficiency compared to the untreated devices. Notably, the methanol-treated devices achieved an operational lifetime of approximately 28 h under ambient conditions, representing a substantial advancement in device stability and performance. The AT approach is a simple and effective strategy for optimizing the ZMO NPs for next-generation optoelectronic applications.

Aiming for atomic-scale precision alignment for advanced semiconductor devices, area-selective atomic layer deposition (AS-ALD) has garnered substantial attention because of its bottom-up nature that allows precise control of material deposition exclusively on desired areas. In this study, we develop a surface treatment to hinder the adsorption of Si precursor on metal surfaces by using a vapor-phase functionalization of bulky phosphonic acid (PA) self-assembled monolayers (SAMs). Through the chemical vapor transport (CVT) method, the bulky solid PA inhibitor with a fluorocarbon terminal group was effectively vaporized, and the conditions for maximizing the blocking effect of the inhibitor were confirmed by optimizing the process temperature and dwelling time. The unintended PA inhibitors adsorbed on SiO₂ surfaces during the CVT process were selectively removed by post-HF treatment, thereby leading to selective deposition of SiO₂ thin films only on SiO₂ substrates. As a results, SiO₂ film growth on the PA SAM/HF-treated TiN surfaces was suppressed by up to 4 nm with just a single exposure to the long-chain inhibitor, even during the ALD process using highly reactive O₃ reactants. The proposed approach paves the way for highly selective deposition of dielectrics on dielectrics (DoD).

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