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[Frontiers of Nanoscience] Nanostructured Thin Films Volume 14 || Spectroscopic and electrical properties of hybrid thin films for solar cell applications
摘要： Third-generation solar cells are designed in order to be able to fabricate thin film solar cells with solution deposition techniques and to obtain high-efficiency solar cells. There are two types of well-known solution-phase-fabricated solar cells: (1) multilayer structure and (2) bulk heterojunction (BHJ) solar cells. Multilayer structure solar cells are fabricated layer by layer of semiconductors, whereas BHJ solar cells consist of two semiconducting materials mixed in one common solvent and deposited onto a conductive glass substrate. Compared with multilayer structures, the BHJ method enables a reduction of the electron pathways between the two materials. One type of solution process for BHJ solar cells is the polymer-nanocrystal BHJ (or hybrid) solar cell. Hybrid BHJ solar cells are fabricated by blending the conducting polymer and inorganic colloidal NCs, and thus combining the properties of both organic and inorganic nanocrystals semiconductors. In this process, the performance of hybrid BHJ solar cells is influenced by the nanocrystals’ shape, solubility, and surface modification, as these properties are believed to affect the crystals’ incorporation in the polymer matrix.
关键词： bulk heterojunction,charge transport,ligand exchange,solar cells,nanocrystals,thin films,polymer
更新于2025-09-11 14:15:04
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Terahertz plasmonics: The rise of toroidal metadevices towards immunobiosensings
摘要： This work reviews fundamentals and the recent state-of-art achievements in the field of plasmonic biosensing based terahertz (THz) spectroscopy. Being nonpoisonous and nondestructive to the human tissues, THz signals offer promising, cost-effective, and real-time biodevices for practical pharmacological applications such as enzyme reaction analysis. Rapid developments in the field of THz plasmonics biosensors and immunosensors have brought many methodologies to employ the resonant subwavelength structures operating based on the fundamental physics of multipoles and asymmetric lineshape resonances. In the ongoing hunt for new and advanced THz plasmonic biosensors, the toroidal metasensors have emerged as excellent alternates and are introduced to be a very promising technology for THz immunosensing applications. Here, we provide examples of recently proposed THz plasmonic metasensors for the detection of thin films, chemical and biological substances. This review allows to compare the performance of various biosensing tools based on THz plasmonic approach and to understand the strategic role of toroidal metasensors in highly accurate and sensitive biosensors instrumentation. The possibility of using THz plasmonic biosensors based on toroidal technology in modern medical and clinical practices has been briefly discussed.
关键词： Two-dimensional,Electrocatalysis,Metallic nanocrystals,Renewable energy
更新于2025-09-11 14:15:04
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ZnO nanocrystals shuttled by extracellular vesicles as effective Trojan nano-horses against cancer cells
摘要： The effective application of nanoparticles in cancer theranostics is jeopardized by their aggregation in biological media, rapid degradation and clearance. The design of biomimetic nanoconstructs with enhanced colloidal stability and non-immunogenicity is therefore essential. We propose naturally stable cell-derived extracellular vesicles to encapsulate zinc oxide (ZnO) nanocrystals as efficacious nanodrugs, to obtain highly biomimetic and stable Trojan nano-horses (TNHs). Materials & methods: Coupling efficiency, biostability, cellular cytotoxicity and internalization were tested. Results: In vitro studies showed a high internalization of TNHs into cancer cells and efficient cytotoxic activity thanks to ZnO intracellular release. Conclusion: TNHs represent an efficient biomimetic platform for future nanotheranostic applications, with biomimetic extracellular vesicle-lipid envelope, facilitated ZnO cellular uptake and potential therapeutic implications.
关键词： biomimetics,extracellular vesicles,colloidal stability,cytotoxicity,nanocrystals,zinc oxide
更新于2025-09-11 14:15:04
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Nanostructured colloidal quantum dots for efficient electroluminescence devices
摘要： The exceptional quality of light generated from colloidal quantum dots has attracted continued interest from the display and lighting industry, leading to the development of commercial quantum dot displays based on the photoluminescence down-conversion process. Beyond this technical level, quantum dots are being introduced as emissive materials in electroluminescence devices (or quantum dot-based light-emitting diodes), which boast high internal quantum efficiency of up to 100%, energy efficiency, thinness, and flexibility. In this review, we revisit various milestone studies regarding the core/shell heterostructures of colloidal quantum dots from the viewpoint of electroluminescence materials. Development of nanostructured colloidal quantum dots advanced from core/shell heterostructure, core/thick shell formulation, and delicate control of confinement potential shape has demonstrated close correlation of the photophysical properties of quantum dots with the performance of electroluminescence device, which provided useful guidelines on the heterostructured quantum dots for mitigating or eliminating efficiency limiting phenomena in quantum dot light emitting diodes. To enable practical and high performance quantum dot-based electroluminescence devices in the future, integration of design concepts on the heterostructures with environmentally benign systems will be crucial.
关键词： Electroluminescence,Nanocrystals,Colloidal Quantum Dots,Core/Shell Heterostructures,Light Emitting Diodes
更新于2025-09-11 14:15:04
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Cellulose-Based Microparticles for Magnetically Controlled Optical Modulation and Sensing
摘要： Responsive materials with birefringent optical properties have been exploited for the manipulation of light in several modern electronic devices. While electrical fields are often utilized to achieve optical modulation, magnetic stimuli may offer an enticing complementary approach for controlling and manipulating light remotely. Here, the synthesis and characterization of magnetically responsive birefringent microparticles with unusual magneto-optical properties are reported. These functional microparticles are prepared via a microfluidic emulsification process, in which water-based droplets are generated in a flow-focusing device and stretched into anisotropic shapes before conversion into particles via photopolymerization. Birefringence properties are achieved by aligning cellulose nanocrystals within the microparticles during droplet stretching, whereas magnetic responsiveness results from the addition of superparamagnetic nanoparticles to the initial droplet template. When suspended in a fluid, the microparticles can be controllably manipulated via an external magnetic field to result in unique magneto-optical coupling effects. Using a remotely actuated magnetic field coupled to a polarized optical microscope, these microparticles can be employed to convert magnetic into optical signals or to estimate the viscosity of the suspending fluid through magnetically driven microrheology.
关键词： magneto-optical properties,polarized light,cellulose nanocrystals,microfluidics,microparticles
更新于2025-09-11 14:15:04
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Microwave-Assisted Synthesis and Assembly of Hyperbranched supra Quantum Dot CdE (E = S, Se, Te) Nanocrystals
摘要： Dichalcogenides are alternatives for synthesis of nano metalchalcogenides which provides a variety of precursors with different reactivities. Using disulfide, diselenide and ditelluride and their mixtures, metalchalcogenide nanocrystals (NCs) in which structures vary from spherical NCs with diameters of ~4 nm to large, hyperbranched NCs with diameters approaching 200 nm are synthesized. Study of the effects of the reaction temperature, concentration and ratio of reactants shows that hyperbranched supra quantum dots (HSQDs) form in three steps: nucleation, aggregation and kinetically-controlled growth. By tuning the concentration of precursors and reaction temperature, both aggregation and growth can be modulated and tetrapod NCs with arms of tunable length and thickness can be prepared. The more reactive precursor forms small NCs which work as a platform for formation of the arms from the less reactive precursor, providing controlled growth on the more reactive facets. By controlling the precursor ratio, the composition of the HSQDs can be controlled.
关键词： dichalcogenides,Microwave synthesis,asymmetric nanocrystals,oriented attachment
更新于2025-09-11 14:15:04
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Real colloidal quantum dot structures revealed by high resolution analytical electron microscopy
摘要： The development of bright and photostable colloidal quantum dots has been a truly interdisciplinary feat. Designing a specific composition of core and shell materials and then producing the desired nanoarchitecture through chemical routes require a blend of physical and inorganic chemistry, solid-state physics, and materials science. In a battle to separate charge carriers from a surface wrought with defect states, complex shell structures with precisely specified gradient compositions have been engineered, producing nanosized emitters with exceptional stability and color purity. However, much of the success has resided in II-VI materials, such as CdSe, and progress is only just being made on cadmium-free quantum dots. This perspective will discuss the primary challenges in engineering colloidal quantum dots and highlight how the advent of advanced analytical electron microscopy is revealing the structure-function relationships of these complex systems.
关键词： photostability,nanocrystals,CdSe,colloidal quantum dots,electron microscopy
更新于2025-09-11 14:15:04
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Evaluating glucose and mannose profiles in Candida species using quantum dots conjugated with Cramoll lectin as fluorescent nanoprobes
摘要： Glycoconjugates found on cell walls of Candida species are fundamental for their pathogenicity. Laborious techniques have been employed to investigate the sugar composition of these microorganisms. Herein, we prepared a nanotool, based on the fluorescence of quantum dots (QDs) combined with the specificity of Cramoll lectin, to evaluate glucose/mannose profiles on three Candida species. The QDs-Cramoll conjugates presented specificity and bright fluorescence emission. The lectin preserved its biological activity after the conjugation process mediated by adsorption interactions. The labeling of Candida species was analyzed by fluorescence microscopy and quantified by flow cytometry. Morphological analyses of yeasts labeled with QDs-Cramoll conjugates indicated that C. glabrata (2.7 μm) was smaller when compared to C. albicans (4.0 μm) and C. parapsilosis sensu stricto (3.8 μm). Also, C. parapsilosis population was heterogeneous, presenting rod-shaped blastoconidia. More than 90% of cells of the three species were labeled by conjugates. Inhibition and saturation assays indicated that C. parapsilosis had a higher content of exposed glucose/mannose than the other two species. Therefore, QDs-Cramoll conjugates demonstrated to be effective fluorescent nanoprobes for evaluation of glucose/mannose constitution on the cell walls of fungal species frequently involved in candidiasis.
关键词： Candida,Cratylia mollis,Bioconjugation,Semiconductor nanocrystals,Lectin
更新于2025-09-11 14:15:04
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Femtosecond-laser-ablation induced transformations in the structure and surface properties of diamond-like nanocomposite films
摘要： Femtosecond laser ablation processing is applied for surface modification and micropatterning of diamond-like nanocomposite (DLN) films (a-C:H:Si:O films). Using a visible femtosecond laser (wavelength 515 nm, pulse duration 320 fs), microgroove patterns have been fabricated on the DLN films, aimed at further studies of their properties. The studies were focused on (i) structural transformations in the surface layers using Raman spectroscopy and transmission electron microscopy (TEM), (ii) wettability of laser-patterned films, and (iii) nano/microscale friction properties of laser-patterned DLN films using lateral force microscopy. Raman spectroscopy and TEM data showed characteristic features of the surface graphitization during ultrashort-pulse ablation. High resolution TEM study of the microgrooves revealed the formation of cubic SiC nanocrystals (4–8 nm size) on the laser-ablated surface. The water contact angle measurements showed anisotropic wetting behavior of the grooved surfaces (the contact angle was different in the directions parallel and perpendicular to microgrooves), depending on the groove depth (aspect ratio). Lateral force microscopy examination (with micro-sized Si tips) showed that the laser-patterned regions exhibited low friction properties compared to the original surface. The obtained results demonstrate that femtosecond laser processing is an effective technique to generate new properties of hard DLN coatings at the micro and macroscale.
关键词： Diamond-like nanocomposite films,Femtosecond laser ablation,Micropatterning,SiC nanocrystals,Graphitization,Wettability
更新于2025-09-11 14:15:04
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Colloidal ReO3 Nanocrystals: Extra Re d-electron instigating a plasmonic response
摘要： Rhenium (+6) oxide (ReO3) is metallic in nature, which means it can sustain localized surface plasmon resonance (LSPR) in its nanocrystalline form. Herein, we describe the colloidal synthesis of nanocrystals (NCs) of this compound, through a hot-injection route entailing the reduction of rhenium (+7) oxide with a long chain ether. This synthetic protocol is fundamentally different from the more widely employed nucleophilic lysing of metal alkylcarboxylates for other metal oxide NCs. Owing to this difference, the NC surfaces are populated by ether molecules through an L-type coordination along with covalently bound (X-type) hydroxyl moieties, which enables easy switching from nonpolar to polar solvents without resorting to cumbersome ligand exchange procedures. These as-synthesized NCs exhibit absorption bands at around 590 nm (≈2.1 eV) and 410 nm (≈3 eV), which were respectively ascribed to their LSPR and interband absorptions by Mie theory simulations and Drude modeling. The LSPR response arises from the oscillation of free electron density created by the extra Re d-electron per ReO3 unit in the NC lattice, which resides in the conduction band. Further, the LSPR contribution facilitates the observation of dynamic optical modulation of the NC films as they undergo progressive electrochemical charging via ion (de)insertion. Ion (de)insertion leads to distinct dynamic optical signatures, and these changes are reversible in a wide potential range depending on the choice of the ion (lithium or tetrabutylammonium). Nanostructuring in ReO3 and the description of the associated plasmonic properties of these NCs made this optical modulation feasible, which were hitherto not reported for the bulk material. We envisage that the synthetic protocol described here will facilitate further exploration of such applications and fundamental studies of these plasmonic NCs.
关键词： Localized surface plasmon resonance,Colloidal synthesis,ReO3 nanocrystals,Electrochemical charging,Optical modulation
更新于2025-09-11 14:15:04