An Analytical Model for the Ordered Nanopore Array Diode Laser

In this work, we present an analytical model describing the density of states and spectral behavior of the ordered nanopore array diode laser. The nanopore structure consists of an ordinary quantum well perturbed by a periodic lattice of energy barriers. It is shown that such a perturbation leads to the formation of energy subbands in both the conduction and valence bands. The theoretically predicted gain spectrum shows excellent agreement with experimental results. Finally, the unique effects of in-plane quantization and periodicity on the intersubband selection rules are described in detail.      

Enhanced Charge Injection Through Nanostructured Electrodes for Organic Field Effect Transistors

Nanosphere lithography is used to process nanopore‐structured electrodes, which are applied into the fabrication of bottom‐gate, bottom‐contact configuration organic field effect transistors (OFETs) to serve as source/drain elecrodes. The introduction of this nanopore‐structure electrode facilitates the forming of nanopore‐structure pentacene layers with small grain boundaries at the electrode interface, and then reduces the contact resistance, contact‐induces the growth of pentacene and accordingly improves the mobility of charge carriers in the OFETs about 20 times as compared with results in literature through enhancing the charge carrier injection. It is believed that this structure of electrode is a valuable approach for improving organic filed effect transistors.     

Graphite versus graphene:plasmonic nanopore DNA sequencing

The plasmonic-based graphite-and graphene-nanopores have been investigated by employing the hybrid quantum/classical scheme(HQCS). Transverse, longitudinal, and total absorption spectra obtained from HQCS are analyzed for the graphite and graphene nanopores. Analyses were examined for each structure in the presence of deoxyribonucleic acid(DNA) nucleobases. The simple excitation of the total mode in graphene nanopore shows the best selectivity for DNA sequencing. A novel method based on the tran...     

Modeling of optimum size and shape for high photovoltaic performance of poly(3-hexylthiophene) nanopore in interdigitated bilayer organic solar cells

The interdigitated design for donor–acceptor in solar cell has been studied in some detail, but the optimum size and shape leading to direct enhancement in nanopore (or nanopillar) structure is still not well understood. Here, we demonstrate a modeling method to forecast the optimum size and shape for poly(3-hexylthiophene) (P3HT) nanopores in interdigitated P3HT: [6, 6]-phenyl C₆₁ butyric acid methyl ester (PCBM) photovoltaic device, based on experimental results of P3HT:PCBM bilayer solar cell. In our analysis, the energy generated at unit nanopore is supposed to the same as the one generated at infinite point of P3HT:PCBM bilayer solar cell with variable layer thickness. A definitive function in terms of a radius of unit nanopore with various shapes is established, substituting a regression function derived from the results of power conversion efficiency in bilayer solar cell. Interpreting the function, we finally showed that the effective radius for P3HT nanopores with rectangular or cylinder, cut-cone, cone shape should be less than 135, 53, 2 nm respectively.     

Ordered Honeycomb Structure Surface Generated by Breath Figures for Liquid Reprography

In this paper, photoelectric cooperative induced patterned wetting is demonstrated on a hydrophobic ordered polymeric honeycomb structure surface, which is prepared by BF method, then photosensitizing with a dye and hydrophobizing with low‐surface‐energy materials; finally, photoelectric cooperative induced patterned wetting is achieved on such a hydrophobic honeycomb structure surface. These results indicate that this work is promising for broadening the applications of photoelectric cooperative liquid reprography, which break the limitations of only using inorganic materials and super‐hydrophobic materials. It should be of great scientific interest to extend the relevant research from inorganic nanorod, nanopore, and nanotube structures to polymeric honeycomb structures, because polymeric materials can overcome the inherent drawbacks of the inorganic materials owing to their advantages of low specific weight, flexibility, tunable material properties, and wide variety.     

Integrating Ionic Gate and Rectifier Within One Solid‐State Nanopore via Modification with Dual‐Responsive Copolymer Brushes

A dual‐functional nanofluidic device is demonstrated that integrates the ionic gate and the ionic rectifier within one solid‐state nanopore. The functionalities are realized by fabricating temperature‐ and pH‐responsive poly(N‐isopropyl acrylamide‐co‐acrylic acid) brushes onto the wall of a cone‐shaped nanopore. At ca. 25 °C, the nanopore works on a low ion conducting state. When the temperature is raised to ca. 40 °C, the nanopore switches to a high ion conducting state. The closing/opening of the nanopore results from the temperature‐triggered conformational transition of the attached copolymer brushes. Independently, in neutral and basic solutions, the conical nanopore rectifies the ionic current. While in acid solutions, no ion rectifying properties can be found. The charge properties of the copolymer brushes, combined with the asymmetrical pore geometry, render the nanopore a pH‐tunable ionic rectifier. The chemical modification strategy could be applied to incorporate other stimuli‐responsive materials for designing smart multi‐functional nanofluidic systems resembling the “live” creatures in nature.     

Real‐Time Probing Nanopore‐in‐Nanogap Plasmonic Coupling Effect on Silver Supercrystals with Surface‐Enhanced Raman Spectroscopy

Nanopore structures have displayed attractive prospects in diverse important applications such as nanopore‐based biosensors and enhanced spectroscopy. However, on the one hand, the fabrication techniques to obtain sub‐10 nm sized nanopores so far is very limited. On the other hand, the electromagnetic enhancement of nanopores is still relatively low. In this work, using a facile chemical etching strategy on 2D plasmonic Ag nanoparticle supercrystals, fine nanopore arrays with sub‐10 nm pore size have been successfully fabricated and a “nanopore‐in‐nanogap” hybrid plasmon mode has been investigated. An in situ etching and surface‐enhanced Raman spectroscopy (SERS) detection indicate that novel hybrid plasmon structure may create an enhanced electromagnetic coupling and increase SERS signal at ≈10× magnification. The breaking of plasmon bonding dipolar mode and generation of antibonding‐like plasmon mode contribute to this enhanced electromagnetic coupling. The facile etching strategy, as a common approach, may open the doors for the fabrication of nanopores in various compositions for numerous applications.     

Investigation of the Metal Deposited into Nanopores of Anodic Alumina upon Fabricating Substrates for Microelectronic Devices

Anodic alumina containing nickel deposited into its nanopores was investigated using a scanning electron probe microanalyzer and an X-ray microdiffractometer. It was demonstrated that electrochemically deposited nickel contains no foreign impurities, has the crystal structure, and is uniformly distributed over the nanopore height.     

Low-temperature electroluminescence from an ordered nanopore array diode laser

We report the first study of spontaneous emission from an ordered nanopore array diode laser at 77 K. The presence of gaps in the spontaneous emission spectrum supports the theoretically predicted formation of a subband structure in the valence and conduction bands.     

DNA Sensing Using Nanocrystalline Surface‐Enhanced Al2O3 Nanopore Sensors

A new solid‐state, Al₂O₃ nanopore sensor with enhanced surface properties for the real‐time detection and analysis of individual DNA molecules is reported. Nanopore formation using electron‐beam‐based decomposition transforms the local nanostructure and morphology of the pore from an amorphous, stoichiometric structure (O to Al ratio of 1.5) to a heterophase crystalline network, deficient in O (O to Al ratio of ≈0.6). Direct metallization of the pore region is observed during irradiation, thereby permitting the potential fabrication of nanoscale metallic contacts in the pore region with application to nanopore‐based DNA sequencing. Dose‐dependent phase transformations to purely γ and/or α‐phase nanocrystallites are also observed during pore formation, allowing for surface‐charge engineering at the nanopore/fluid interface. DNA transport studies reveal an order‐of‐magnitude reduction in translocation velocities relative to alternate solid‐state architectures, accredited to high surface‐charge density and the nucleation of charged nanocrystalline domains. The unique surface properties of Al₂O₃ nanopore sensors make them ideal for the detection and analysis of single‐stranded DNA, double‐stranded DNA, RNA secondary structures, and small proteins. These nanoscale sensors may also serve as useful tools in studying the mechanisms driving biological processes including DNA–protein interactions and enzyme activity at the single‐molecule level.     

Photoelectric Cooperative Induced Wetting on Aligned‐Nanopore Arrays for Liquid Reprography

Surface wettability as a response to the cooperation of different stimuli has been intensively studied and provides more advantages than as a response to a single stimulus. Recently, we demonstrated the patterned wettability transition from the Cassie to the Wenzel state on a superhydrophobic aligned‐ZnO‐nanorod array surface via a photoelectric cooperative wetting process. However, the specific aligned‐nanorod array structure of such devices is easily damaged due to their low mechanical strength and cannot sustain multiple transfer printing. Meanwhile, the patterned wetting process is not easily controlled due to the air‐permeable structure of adjacent nanorods. As a result, in practice, it is difficult to apply liquid reprography on such a nanostructure. Here, we demonstrate photoelectric cooperative induced patterned wetting on the superhydrophobic aligned‐nanopore array surface of TiO₂‐coated nanoporous AAO film, which has a high mechanical strength and excellent controllability. Liquid reprography is achieved through the patterned wetting process on the superhydrophobic aligned‐nanopore array surface, which is a new progression in liquid reprography, and is promising for gearing up the application of photoelectric cooperative liquid reprography.     

应用纳米孔的脱氧核糖核酸序列测定技术

DNA链是由成千上万个碱基对组成,从生物物理学角度分析,DNA分子链结构与电学性质决定了在技术上可能一次性地在DNA链穿越纳米孔时对其进行测序。本文从生物物理学角度分析DNA分子链结构与电学性质,并对纳米孔的构建材料作了初步实践。     

Specific Biosensing Using DNA Aptamers and Nanopores

The multiplexed biosensing of target molecules with high specificity and accuracy is of fundamental importance in both biological research and medical diagnostics. In this paper, the working range of the recent nanopore‐DNA carrier based method is extended by introducing a two‐step assay using specific DNA aptamers. A signal translation step allows for binding of the target in physiological conditions before the nanopore measurements. Using protein encoded DNA carriers, the simultaneous detection of three targets spanning several orders of magnitude in molecular weight is demonstrated. The single‐molecule method may be integrated into nanopore sensing devices for future applied research and point‐of‐care applications.     

pH‐Responsive Nanoporous Silica Colloidal Membranes

Free‐standing colloidal membranes (nanofrits) with varied thickness and nanopore size are fabricated and modified with pH‐responsive poly(2‐(dimethylamino)ethyl methacrylate) brushes. The polymer‐modified nanofrits demonstrate excellent gating behavior for molecular diffusion: in the presence of acid, the diffusion rate of positively charged species significantly decreases. Increasing the polymer length and membrane thickness and decreasing the nanopore size leads to the complete acid‐controlled gating of the membranes.     

Enhanced DNA Sequencing Performance Through Edge‐Hydrogenation of Graphene Electrodes

The use of graphene electrodes with hydrogenated edges for solid‐state nanopore‐based DNA sequencing is proposed, and molecular dynamics simulations in conjunction with electronic transport calculations are performed to explore the potential merits of this idea. The results of the investigation show that, compared to the unhydrogenated system, edge‐hydrogenated graphene electrodes facilitate the temporary formation of H‐bonds with suitable atomic sites in the translocating DNA molecule. As a consequence, the average conductivity is drastically raised by about 3 orders of magnitude while exhibiting significantly reduced statistical variance. Furthermore, the effect of the distance between opposing electrodes is investigated and two regimes identified: for narrow electrode separation, the mere hindrance due to the presence of protruding hydrogen atoms in the nanopore is deemed more important, while for wider electrode separation, the formation of H‐bonds becomes the dominant effect. Based on these findings, it is concluded that hydrogenation of graphene electrode edges represents a promising approach to reduce the translocation speed of DNA through the nanopore and substantially improve the accuracy of the measurement process for whole‐genome sequencing.     

Graphene Nanopores for Protein Sequencing

An inexpensive, reliable method for protein sequencing is essential to unraveling the biological mechanisms governing cellular behavior and disease. Current protein sequencing methods suffer from limitations associated with the size of proteins that can be sequenced, the time, and the cost of the sequencing procedures. This study reports the results of all‐atom molecular dynamics simulations that investigated the feasibility of using graphene nanopores for protein sequencing. The study is focused on the biologically significant phenylalanine‐glycine repeat peptides (FG‐nups)—parts of the nuclear pore transport machinery. Surprisingly, FG‐nups are found to behave similarly to single stranded DNA: The peptides adhere to graphene and exhibit stepwise translocation when subject to a transmembrane bias or a hydrostatic pressure gradient. Reducing the peptide's charge density or increasing the peptide's hydrophobicity is found to decrease the translocation speed. Yet, unidirectional and stepwise translocation driven by a transmembrane bias is observed even when the ratio of charged to hydrophobic amino acids is as low as 1:8. The nanopore transport of the peptides is found to produce stepwise modulations of the nanopore ionic current correlated with the type of amino acids present in the nanopore, suggesting that protein sequencing by measuring ionic current blockades may be possible.     

An Accurate DNA Sensing and Diagnosis Methodology Using Fabricated Silicon Nanopores

Nanopore-based biomolecular sensing is an emerging nanotechnology which relies on the ability to measure changes in ionic conductance of single nanoscale pores as biomolecular analytes are driven through them, one at a time, by an applied electric field. Nanopores constructed from self-assembled proteins as well as using silicon-based fabrication techniques have been demonstrated to allow sizing and identification of DNA, RNA, proteins, and other biomolecules many times faster than with current technology. Despite the potential of nanopore sensing to produce "next generation" biomolecule analysis devices, its current demonstrations are based on the use of a simple dc stimulus across the nanopore. As a result, the resolution obtained is insufficient for many practical applications. In this paper, we report a novel diagnosis methodology for nanopore sensors based on optimization of a generalized electrical stimulus and a microscopic model of the biomolecule transport process. This methodology is applied to analyze the size distribution of an arbitrary mixture of DNA strands, which is a critical step in DNA sequencing. A transport model for long polymers in nanopores is built and parameterized to reproduce existing experimental data. The electrical stimulus is optimized "on-the-fly" using the model, to obtain a significant increase in the sizing resolution for any given range of DNA sizes and hence a clear identification of all sizes of DNA in the mixture. Hence, it is proposed that nanopore-based DNA sensing can be advanced significantly incurring no (or minimal) hardware overhead, by a combination of optimized stimuli and microscopic transport modeling     

Highly Efficient Osmotic Energy Harvesting in Charged Boron-Nitride-Nanopore Membranes

Recent studies of the high energy-conversion efficiency of the nanofluidic platform have revealed the enormous potential for efficient exploitation of electrokinetic phenomena in nanoporous membranes for clean-energy harvesting from salinity gradients. Here, nanofluidic reverse electrodialysis (NF-RED) consisting of vertically aligned boron-nitride-nanopore (VA-BNNP) membranes is presented, which can efficiently harness osmotic power. The power density of the VA-BNNP reaches up to 105 W m⁻², which is several orders of magnitude higher than in other nanopores with similar pore sizes, leading to 165 mW m⁻² of net power density (i.e., power per membrane area). Low-pressure chemical vapor deposition technology is employed to uniformly deposit a thin BN layer within 1D anodized alumina pores to prepare a macroscopic VA-BNNP membrane with a high nanopore density, ≈10⁸ pores cm⁻². These membranes can resolve fundamental questions regarding the ion mobility, liquid transport, and power generation in highly charged nanopores. It is shown that the transference number in the VA-BNNP is almost constant over the entire salt concentration range, which is different from other nanopore systems. Moreover, it is also demonstrated that the BN deposition on the nanopore channels can significantly enhance the diffusio-osmosis velocity by two orders of magnitude at a high salinity gradient, resulting in a huge increase in power density.     

硅基底电子束蒸发铝膜阳极氧化特性

研究了硅衬底上电子束蒸发铝膜 ,在 H2 SO4 水溶液中阳极氧化形成硅衬底多孔氧化铝复合结构的过程 .硅衬底电子束蒸发铝膜的阳极氧化过程主要由多孔氧化铝的生长、氧化铝生长向氧化硅生长的过渡和氧化硅生长三个阶段构成 .硅衬底多孔氧化铝复合结构的透射电子显微镜观察表明 ,在硅衬底上形成了垂直于硅表面的氧化铝纳米孔 ,而孔底可形成 Si O2 层 .有序结构多孔氧化铝的形成不依赖于铝膜的结晶状态 ,而是由阳极氧化过程的自组织作用所决定的 .实验表明将多孔氧化铝制备工艺移植到硅基衬底上直接形成硅基衬底多孔氧化铝复合结构是可行的