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Step-growth polymerization of traptavidin-DNA conjugates for plasmonic nanostructures
摘要： Here, we use two important biomaterials, protein and DNA, to construct self-assembled nanostructures through Watson-Crick base-paring of DNAs. We apply a simple magnetic separation method to purify traptavidin-DNA conjugates, and demonstrate synthesis of linear arrays of traptavidin-DNA conjugates via the step-growth polymerization approach with pre-determined DNA sequences. Using the traptavidin-DNA array as a template, we assemble gold nanoparticles to form linear plasmonic nanostructures in a programmable manner. The traptavidin-DNA conjugates thus provide a convenient platform for one-dimensional assembly of biotinylated nanomaterials for many biomedical applications from drug delivery to bio-sensing.
关键词： Traptavidin,Plasmonic nanostructure,Supramolecular assembly,Protein-DNA conjugate,DNA nanostructure
更新于2025-09-12 10:27:22
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Red Emitting InGaN‐Based Nanocolumn LEDs with Highly Directional Beam Profiles
摘要： We demonstrated a red emitting (λ = 637 nm) nanocolumn LED with highly directional beam profiles. The radiation angle of the red nanocolumn LED was approximately ±30°, which is narrower than that of ordinary planar-type LEDs. Such excellent emission characteristics caused by the photonic crystal effect will provide a key technology for applications of nanocolumn micro-LEDs in displays.
关键词： light-emitting diode,nanostructure,nitride,photonic crystal
更新于2025-09-12 10:27:22
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Improved growth conditions of pulsed laser-deposited PbI2 nanostructure film: towards high- photosensitivity PbI2/CNTs/Si photodetectors
摘要： Nanostructured PbI2 films were grown by laser deposition technique at a substrate temperature of 45?°C was demonstrated. Herein, we attempted to improve and control the crystal growth of PbI2 film and p-PbI2/MWCNTs/p-Si photodetector by finding the optimum laser fluence. X-ray diffraction XRD results illustrate that the grown PbI2 films are polycrystalline with hexagonal structure along (001) and the film crystallinity degraded with increasing the laser fluence. Scanning electron microscope SEM revealed that the particle size decreases as laser fluence increase and film deposited at 3.9?J/cm2 was dense and the grains distributed uniformly over the surface of the film. Energy dispersive X-ray EDX data confirms that the film stoichiometry depends on laser fluence and the film deposited at 3.9?J/cm2 was stoichiometric PbI2. The Photosensitivity investigations reveal that responsivity as high as 0.4 A/W at 610?nm was obtained for the p-PbI2/MWCNTs/p-Si photodetector prepared at 3.9?J/cm2 without post-deposition annealing.
关键词： photodetector,nanostructure film,PbI2,pulsed laser deposition,laser fluence
更新于2025-09-12 10:27:22
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A Novel Way for Improving the Overall Photoelectric Conversion Efficiency of Dye Sensitized TiO 2 Solar Cells
摘要： The past several years has witnessed a sharp increase in the number of scientists and researchers who have attached great importance to studying Dye sensitized solar cells (DSSCs) because of its low cost and potential high photoelectric conversion efficiency. There are two main factors that influence the photoelectric conversion efficiency of dye sensitized solar cells. One is the low photon absorption rate of solar cells, and other one is the low transmission rate of the photo-generated electrons through the thick nanocrystalline film. So in order to further research and improve efficiency, an accurate model using COMSOL Multiphysics is investigated to reveal the photoresponse and current transport processes of DSSC. Specifically, an optical model is studied to determine how much the solar energy each cell takes in, and an electrical model is investigated to determine how much the overall efficiency. Besides, three adjusted micro/nanostructures of DSSCs have been built for improving the efficiency. The study shows that a more suitable structure can collect more solar energy and improve the electronic diffusion efficiency so as to improve the overall photoelectric conversion efficiency of DSSC.
关键词： Dye sensitized solar cells (DSSCs),COMSOL Multiphysics,Photoelectric coupling simulation,Micro/nanostructure
更新于2025-09-12 10:27:22
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Metal Oxide Grating based Plasmonic Refractive Index Sensor with Si layer in Optical Communication Band
摘要： Nanostructure based devices are crucial for many applications including surface plasmon resonance (SPR) sensors, in particular. In this work, an aluminum oxide (Al2O3) grating based plasmonic sensor with Si and Ag layers is proposed and simulated for the detection of hemoglobin (Hb) concentration (en route its refractive index measurement) in human blood in optical communication band (1400-1550 nm). The simulations are based on rigorous coupled wave analysis (RCWA). In general, a plasmonic sensor’s performance is closely evaluated in terms of sensitivity and figure of merit (FOM) but we have also extended the analysis by considering the SPR curves (of both reference and analyte samples) even more meticulously in terms of spectral FOM (FOM*) based on depth of reflectance curve. In order to further deepen the performance analysis, a quality factor (QF) is introduced by combining the maximum FOM* (m-FOM*) and FWHM of the analyte SPR curve. The effect of grating variables and the thicknesses of Si and Ag layers on FOM* and QF is analyzed. The simulation results are explained in relevant physical concepts such as radiation damping. The results indicate that the proposed sensor with optimized design parameters is able to provide significantly better sensitivity, detection limit, FOM, and m-FOM* compared with existing grating-based SPR sensors.
关键词： RCWA,Plasmonic nanostructure,grating,sensor,metal oxide,figure-of-merit
更新于2025-09-12 10:27:22
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A novel shaped-controlled fabrication of nanopore and its applications in quantum electronics
摘要： High-intensity (107–108 A m?2) electron beams can be used to fabricate nanoscale pores. this approach enables real-time observation of nanopore drilling and precise control of the diameter of the nanopore. nevertheless, it is not suitable for tuning the nanopore’s sidewall shape. in this study, we demonstrate the use of low-intensity electron beams to fabricate nanopores on a silicon nitride (Sinx) membrane. this technique allows the precise adjustment of the nanopore dimension and the shaping of its three-dimensional (3D) nanostructure. The 3D structures of the nanopore were evaluated by electron tomography, and series of oblique images were used in reconstructing the 3D images of nanopores using a weighted back-projection method. the sidewall shape of the nanopore was observed at different electron-beam conditions, and the formation mechanism was elucidated based on these results. the nanopore fabricated with this technique can be used as a template to develop electronics at the nanoscale based on which a quantum-dot device can be prepared with a simple evaporation process. The measured results show that the device can resolve well-defined electronic states that are characteristic for the behaviors of the quantum-dot device.
关键词： electron beam,nanopore,3D nanostructure,quantum electronics,silicon nitride membrane
更新于2025-09-12 10:27:22
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Label-free, real-time on-chip sensing of living cells via grating-coupled surface plasmon resonance
摘要： The application of nanotechnologies to address biomedical questions is a key strategy for innovation in biomedical research. Among others, a key point consists in the availability of nanotechnologies for monitoring cellular processes in a real-time and label-free approach. Here, we focused on a grating-coupled Surface Plasmon Resonance (GC-SPR) sensor exploiting phase interrogation. This sensor can be integrated in a microfluidic chamber that ensures cell viability and avoids cell stress. We report the calibration of the sensor response as a function of cell number and its application to monitor cell adhesion kinetics as well as cell response to an external stimulus. Our results show that GC-SPR sensors can offer a valuable alternative to prism-coupled or imaging SPR devices, amenable for microfluidic implementation.
关键词： Grating,Nanostructure,Surface plasmon resonance,Live cells
更新于2025-09-12 10:27:22
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Manipulating nanoscale structure to control functionality in printed organic photovoltaic, transistor and bioelectronic devices
摘要： Printed electronics is simultaneously one of the most intensely studied emerging research areas today. For the past decade the potential for organic electronic materials to revolutionize this printed electronics space has been widely promoted. Such conviction in the potential of these carbon-based semiconducting materials arises from their ability to be dissolved in solution, and thus the exciting possibility of simply printing a range of multifunctional devices onto flexible substrates at high speeds for very low cost using standard roll-to-roll printing techniques. However, the transition from promising laboratory innovations to large scale prototypes requires precise control of nanoscale material and device structure across large areas during printing fabrication. Maintaining this nanoscale material control during printing presents a significant new challenge that demands the coupling of organic electronic materials and devices with clever nanoscience fabrication approaches that are adapted to the limited thermodynamic levers available. In this review we present an update on the strategies and capabilities that are required in order to manipulate the nanoscale structure of large area printed organic photovoltaic, transistor and bioelectronic devices in order to control their device functionality. This discussion covers a range of efforts to manipulate the electroactive ink materials and their nanostructured assembly into devices, and also device processing strategies to tune the nanoscale material properties and assembly routes through printing fabrication. The ability to control material properties on the nanoscale whilst simultaneously printing functional devices on the square metre scale is prompting a feedback loop between laboratory nanoscience innovations and their feasibility in adapting to large scale printing fabrication. The review finishes by highlighting progress in printed organic electronic devices that provide a pathway towards innovative developments in the targeted nanoscience required for organic photovoltaic, transistor and biofunctional devices.
关键词： organic electronics,biocompatible,printing,large area,nanostructure,semiconductors
更新于2025-09-12 10:27:22
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Self-assembled highly porous rugby-like hierarchical ZnO thin film formaldehyde gas sensor
摘要： A new rugby-like ZnO thin film was self-assembled via a hydrothermal method and the influences of the hydrothermal temperature on crystal growth and gas sensing properties of ZnO thin films were investigated. The results showed that the highly porous rugby-like ZnO crystals were self-assembled via thin fan-shape sheets with abundant nanopores formed by interconnected the smaller nanoplates when the hydrothermal temperature was 140 (cid:1)C. Its specific surface area value reached 45.0 m2 g(cid:3)1. The sensor exhibited an excellent gas sensing response, a good selectivity towards formaldehyde and quick response characteristics at the optimum working temperature of 250 (cid:1)C.
关键词： self-assemble,zinc oxide,gas sensing property,rugby-like hierarchical nanostructure
更新于2025-09-12 10:27:22
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Design and Analysis of a Ag Rhombus Nanoparticle Film-Coupled Plasmonic Nanostructure
摘要： We design a coupled plasmonic nanostructure, which consists of a Ag rhombus nanoparticle positioned over a silver ?lm, separated by a dielectric spacer layer, and perform numerical analysis by calculating the radiation loss resistance of this nanostructure as the perfect electric conductor metal based on the theory of transmission line modes. Compared with the nanocube or triangular nanodisk ?lm-coupled plasmonic nanostructures introduced in the previous works, a stronger electric ?eld enhancement was achieved in the Ag rhombus nanoparticle ?lm-coupled nanostructure because of the fact that the sharp tip of the rhombus nanoparticle can generate ?eld enhancement at a hot spot. In order to demonstrate that the sharp tip can con?ne the electromagnetic energies strongly, we also have calculated the Purcell factor and the far-?eld directivity of the quantum emitter in the vicinity of this nanostructure.
关键词： Purcell factor,electric ?eld enhancement,plasmonic nanostructure,Ag rhombus nanoparticle,far-?eld directivity
更新于2025-09-11 14:15:04