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Expert Reviews
tiny-roots.jpg Expert Reviews are summaries of newly-published research that demonstrate advances in applications, devices, metrology, and materials that will facilitate the commercial development and/or marketable application of nanoscale systems and devices.
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Nanosensor Arrays Enable Highly Sensitive Chemical Fingerprinting for Explosive Detection

Reliable detection of trace amounts of hazardous chemicals, in particular explosives, remains a pervasive problem due to the broad variety of associated chemical compounds that must be monitored in an open environment. In combination with the inherently low vapor pressures of most explosive compounds, the challenges of detecting potential threats require sensing techniques having ultra-high sensitivity, high selectivity, and rapid response. While such performance is available using sophisticated and expensive equipment, the need exists for portable, low cost systems that can discriminate a broad range of chemical species with high sensitivity and low probability of false responses. A broad range of nanomaterials have proven effective for chem/bio detection due to their high surface to volume ratio, thereby providing high sensitivity. Effective probability of detection has been demonstrated for certain trace chemical analysis by chemically functionalizing the nanomaterial surface such that the analyte of interest has an increased affinity to bind with the nanomaterial surface, which changes the electrical properties of the sensor. While this has enabled a pathway for highly sensitive, low cost sensor platforms, chemical selectivity for detection in open environments remains a challenge. For this, the concept of a chemical nose is ...

Jeff Morse, Ph.D. July 31, 2014 79
Improved Method of Device Area Scale-up for SWNT/Silicon Hybrid Solar Cells Using Silver Nanowires

While research on silicon solar cells has progressed the development of all organic, inorganic, and hybrid materials systems to simultaneously address the diverse set of design criteria for optimal photovoltaic (PV) performance, incorporation of hybrid materials systems has proven to be an effective method to improve some of these issues. With crystalline silicon representing the standard for high efficiency in solar cell designs, cell cost and production capacity remain concerns for the growing emphasis on broad implementation of renewable energy strategies on a global basis, with solar PV being a leading competitor. With recent studies demonstrating that the approach incorporating p-type nano-Carbon with n-type silicon in a hybrid film approach provides excellent diode junction rectification properties, improved collection and transport efficiencies due to the enhanced conductivity of the nano-C film, and superior semiconductor barrier properties at the nano-C/silicon junction. While this has proven effective for small cell design of a few square millimeters, scaling the cell area has proven challenging due to the increase in sheet resistance (Rs) of the nano-C layer as area increases resulting in a reduction in cell efficiency. Recently, Li,, from the Taylor group in the Chemical and Environmental Engineering Departm ...

Jeff Morse, Ph.D. July 02, 2014 205
Solution Processing of ITO-Free Solar Cells

Organic solar cells (OSCs) are of interest for next-generation photovoltaic applications due to their lower costs and milder fabrication requirements relative to c-Si and thin-film devices. The power conversion efficiency (PCE) of these devices has risen to 11-12% in recent years, which is promising in order to gain market share in this competitive field. Requiring only simple spin- or dip-coating techniques, organic or polymer solar cells are an attractive low-cost technology; in recent years, there has been a focus on solution and roll-to-roll high throughput processing of OSCs to lower the fabrication costs even further.

Bradley Fahlman, Department of Chemistry, Central Michigan University, InterNano Editorial Staff March 27, 2014 189
Rapid and Low-Cost Graphene Film Deposition using Solution Processing

In 2004, a single layer of graphite known as graphene was synthesized for the first time via mechanical exfoliation of graphite. This discovery, for which Novoselov and Geim were awarded the Nobel Prize in Physics in 2010, has ushered in a 'graphene frontier' with worldwide interest in exploiting their intriguing potential for technological applications in fields such as nanoelectronics and energy storage. The primary method that is used to fabricate large-scale transparent graphene films is chemical vapor deposition (CVD). However, this requires high-temperature processing and relatively long deposition times. Furthermore, this precludes the deposition of graphene onto temperature-sensitive substrates. Although the deposited films may be flaked off the metallic (usually Cu) substrate for transfer to another surface, this will lead to the incorporation of impurities and structural defects.

Bradley Fahlman, Department of Chemistry, Central Michigan University, InterNano Editorial Staff March 05, 2014 273
Progress and Public Trust in Nanotechnology Require Better Material Characterization

A prevalent challenge for progress in nanotechnology is characterization [1, 2]. Characterization, the measurement of various physicochemical properties of materials, is crucial for the evolution of nanotechnology from rudimentary nanomaterials and devices to those that are precision-engineered, mass producible, and safe. Each of the main sectors of nanotechnology – research, manufacturing, and regulation – needs systematic characterization in order to maximize knowledge and control of nanomaterials. Due to a number of factors, many of the nanomaterials that have been synthesized thus far are poorly defined, which can lead to false generalizations about performance and toxicity. The advancement of nanotechnology depends upon a coordinated effort made by researchers, manufacturers, regulators, and funding agencies to improve characterization techniques and practices so that well-defined and reproducible nanomaterials are studied and manufactured. An important consequence of thoroughly characterized materials will be increased public awareness, acceptance and use of nanotechnology.

Ayla Kiser, Catalan Institute of Nanoscience and Nanotechnology (ICN2) February 27, 2014 217
Nano Counterfeit Protection for Space, Aviation and Defense Electronics

Space and defense electronics are two of the most conservative markets in terms of new materials qualification – unless there is a pressing technical issue. Counterfeiting is a huge issue for space, where recall and repair are excruciatingly expensive, or impractical [1][2]. One of the root causes for a recent failure was alleged to be counterfeit SRAM memory chips. In aviation and defense, the problems may be due to the age of the systems and the reliance and rapid obsolescence of COTS (“commercial-off-the shelf”) electronics with a lifetime of a few years whereas weapons systems have lifetimes of decades. An extreme example is the B-52, first flown in 1952 with a projected retirement date of 2040! Couple this with data quoted by King that 57% of counterfeit-part reports from 2001 through 2012 involved obsolete components and we have a real problem.

Alan Rae, Ph.D., M.B.A. February 26, 2014 110
Wearable Textile Batteries

Portable electronic devices are pervasive in our society, keeping us connected to our offices and families regardless of where we are on the planet. From sensors that track daily caloric intakes and training regimes, to future uses of watching your favorite sporting event on the sleeve of your shirt, it is clear that wearable electronics will play an increasingly important role for consumers. With these advents, it will become paramount that rechargeable batteries be able to be seamlessly interfaced with fabrics to provide the requisite power over extended periods.

Bradley Fahlman, Department of Chemistry, Central Michigan University, InterNano Editorial Staff December 12, 2013 362
Carbon Nanotube-doped Liquid Crystal - Towards Faster LCDs

Liquid crystals (LCs) exhibit a phase of matter that has properties between those of a conventional liquid and those of a solid crystal. So, LCs can flow like a liquid, and at the same time the anisotropic LC-molecules maintain a long range crystalline order. Their unique combinations of liquid and solid-like properties allow liquid crystals to be used pervasively in the electro-optical display technology – known as liquid crystal display (LCD).

Rajratan Basu, US Naval Academy December 12, 2013 963
Virtual Design Methods Provide Strategy for Innovation through Nanomaterial Database Development

Recent materials informatics initiatives are fostering the establishment of open-access, federated databases that catalogue the properties of materials. While an initial emphasis, particularly in the case of nanomaterials, is to understand the toxicological properties of materials, a key goal is to establish model-based materials design methodologies wherein materials properties can be computationally predicted. Such a virtual design approach to materials represents a powerful paradigm in which tools become openly available to design new products, optimize materials performance, and understand the risk associated with human and environmental exposure before the materials has been synthesized. Such an infrastructure will benefit industry, academia, and government agencies alike in providing low cost, rapid turn-around approaches to design, and manufacture materials, incorporate into product designs, and establish the regulatory pathway for workforce and consumer protection.

Jeff Morse, PhD September 26, 2013 263
Hierarchical Integration of Multi-scale Elements for Micro-Fuel Cells

Fuel cell power sources can be an efficient technology for direct conversion of various forms of hydrocarbon fuels to electrical power, and in the case of hydrogen fuel, could provide one of the greenest energy sources available. Fuel cells have the potential to impact application areas including grid scale, automotive, and portable electronics, but the predicted impact has not yet been realized as the manufacturing, cost, and reliability of fuel cell components has not matured sufficiently to be competitive with other power sources. Fuel cell optimization challenges remain due to the need to create a hierarchical materials structure at the triple-phase boundary. This facilitates  effective mass transport of reactants and byproducts with a materials region that incorporates catalyst, electrolyte, and conductor properties within a porous diffusion scaffold. Integrating these nanoscale features with microscale flow field channels requires multiple process steps and materials layers that are typical of fuel cell architectures.

Jeff Morse, PhD July 31, 2013 363
Nanotextured Surfaces Impregnated with Lubricant for Enhanced Condensation

Incorporation of specific nanostructures and textured patterns on surfaces is a growing area of research for controlling surface wetting properties. By tailoring the hydrophobicity for a given surface, enhanced features may be achieved by design such as anti-icing or anti-fog, self-cleaning and repellency to a range of liquids. Another significant area of application for such surfaces is condensation for industrial processes such as power generation, thermal management, air conditioning, desalination, and transportation. Enhancing the heat transfer during condensation will significantly impact the energy efficiency for these applications, further reducing cost and physical impact on the system. Depending on the wettability of the surface, the condensate either forms as a film or as discrete drops on the surface. The latter is more desirable for effective heat transfer, as a film can behave as a thermal barrier, while the dropwise condensate can be continuously shed allowing for renewed nucleation and growth of drops. As a result of these possible advantages, there has been significant interest in developing superhydrophobic surfaces to promote dropwise condensation. Such surfaces to date have typically incorporated complex surface patterns to obtain extreme non-wetting properties in which droplets are formed and sit atop the sur ...

Jeff Morse, PhD October 31, 2012 482
Nanotechnology-enabled Smart Packaging for Longer Produce Shelf-life

In order to optimize produce shelf-life from time of harvest through storage and transportation, smart packaging and sensor technologies are readily being explored and evaluated for various scenarios encountered in the horticultural industry. Recently, Esser et. al. reported on the selective detection of ethylene gas using carbon nanotube-based sensors as a means of determining fruit ripeness.

Jeff Morse, PhD September 28, 2012 1020
Solution Processing of Transparent Polymer Solar Cells

Polymer solar cells (PSCs) are being actively developed for applications in which large area, high-rate solution based processes provide a low-cost alternative to more traditional photovoltaic device technologies. Progress in PSC performance has demonstrated power conversion efficiency exceeding 10% for tandem device architectures, thereby opening the door for competitive cost-performance trade-off for applications such as building integrated photovoltaics, or chargers for portable electronic devices. A related opportunity is transparent PSCs that could be used to generate power from windows on homes and buildings while still allowing people to see outside. While such a smart window technology for generating electricity could find widespread use, the cost and performance targets are even more critical in order to gain market entry. From a technology standpoint, the PSC would have to convert mainly infrared light to electricity, not the visible part of the spectrum, leaving the cells at least 70% transparent to the human eye, while demonstrating power conversion efficiency approaching that of normal PSCs. For manufacturing, the cells would have to be made through solution processing in order to achieve the necessary economy of scale for market acceptance, while further enhancing the value proposition through an extended lifecycle ...

Jeff Morse, PhD July 26, 2012 510
Rapid Assembly of Functional Thin Films Using Spin-Spray Layer-by Layer Processing

Functional nanocomposite thin films are traditionally synthesized by techniques such as casting or dip-coating wherein the quality and properties of the film are determined by the concentrations of the initial dispersion and casting time, with limited parameters to control or tune the properties of the film. Layer-by-layer (LbL) assembly has emerged as a method to circumvent this issue by offering exquisite control over the composition and properties of a multilayer, polymer-nanostructure materials hybrid, and has become an effective method for synthesis of carbon nanotube (CNT)-polymer composite films. LbL assembly utilizes the sequential deposition of polyelectrolyte pairs through a dip-coating procedure. The deposition of materials during each cycle is self-limiting, dictated by the charge concentration of the polyelectrolyte solution and the surface being coated. Yet LbL assembly is still a relatively slow process, requiring time-scales on the order of days to produce films with targeted conductivity and thickness. Utilizing spraying techniques to apply the polyelectrolyte solutions to the substrate, significant reduction in process time has been demonstrated. While spraying the polyelectrolyte-CNT solution is both materially and temporally efficient, the time requirements to deposit thin films remain excessive for batch and ...

Jeff Morse, PhD June 07, 2012 562
Inkjet-Printed Graphene Flexible Electronics

Electronic devices on flexible substrates has been a growing area for research and development due to rapidly expanding applications and markets for touch screens, electronic paper and displays, photovoltaics, lighting, and sensor tags. To achieve the economy of scale for large area substrates requiring active transistor functionality, the primary focus has been to fabricate the electronics directly on the flexible substrate. A typical drawback of this approach is that the fabrication processes must be compatible with the nominally low-temperature plastic materials that are being considered for the substrates. As a result, the semiconductor materials have relatively poor electronic transport properties, which can translate to large switching voltages, as well other performance limitations such as switching current ON/OFF ratio. The most promising materials and processes to date include thin-film metal oxide materials deposited by moderate temperature processes such as chemical vapor deposition (CVD) or atomic layer deposition (ALD), yet there are still concerns associated with substrate compatibility, throughput, and subsequent process integration for final device and circuit designs. In contrast, a range of semiconducting nanomaterials ink formulations have been studied suitable for coating by techniques such as spin-casting, r ...

Jeff Morse, PhD March 30, 2012 1138
Additive-Driven Assembly of Block Copolymer-Nanoparticle Hybrid Materials for Solution Processable Floating Gate Memory

Floating gate memory devices were fabricated using well-ordered gold nanoparticle/block copolymer hybrid films as the charge-trapping layers, SiO2 as the dielectric layer and poly(3-hexylthiophene) as the semiconductor layer.  The charge-trapping layer was prepared via self-assembly. The addition of Au nanoparticles that selectively hydrogen-bond with pyridine in a poly(styrene-b-2-vinyl pyridine) block copolymer yields well-ordered hybrid materials at Au nanoparticle loadings up to 40 wt%. The characteristics of the memory window were tuned by simple control of the Au nanoparticle concentration. This approach enables the fabrication of well-ordered charge storage layers by solution processing, which is extendable for the fabrications of large-area and high-density devices via roll-to-roll processing. 

Qingshuo Wei, Ying Lin, Eric R. Anderson, Alejandro L. Briseno, Samuel P. Gido and James J. Watkins February 07, 2012 601
Voltage Controlled Drug Release from Nanoparticles for Hybrid Smart Drug Delivery Systems

Stimulus-responsive biomaterials are of significant interest as in vivo drug delivery systems. Such materials provide a means for controlled and long-term drug release as new treatments for a range of chronic diseases that require daily injections or precise doses of specific medications. Various materials systems investigated to date have exhibited response to heat, light, pH, enzymes, ultrasonic waves, and magnetic fields. While some interesting performance has been reported utilizing these stimulus methods, activation of these materials typically requires large or specialized equipment. In comparison, electric-field stimulus is much simpler to generate and control. Electrical signals have been shown to release molecules via conducting polymeric bulk materials or implantable electronic delivery devices, yet often require invasive surgery to implant and activate the devices. In order to implement electrically activated drug delivery, a technique is required that encapsulates the drug compound in a platform suitable for injection to a specific locale where the release can be triggered.

Jeff Morse, PhD January 25, 2012 547
Spatial Atomic Layer Deposition for Industrial Scale Nanomanufacturing of Thin Films

Atomic layer deposition (ALD) has emerged over the past decade as a viable alternative to physical and chemical vapor deposition (PVD, CVD) techniques for a range of strategic thin film coatings. This is due to the improved control of thin film properties including the incorporation of extrinsic dopants, reduction of contaminants, and the formation of intrinsic defects during film growth through a low temperature, non-vacuum process. These benefits result from the time-sequenced introduction of precursors in the deposition zone where selective and self-limiting half reactions occur on the surface. In this manner, thin-film growth is determined by surface kinetics, and is able to avoid parasitic gas-phase reactions. As such, film properties can be controlled by variation of temperature and reactant partial pressure. However, conventional time-sequenced ALD is not compatible with many scaled industrial applications as film growth rates (~0.01 nm/s) are rather slow due to the need to purge reactants during each growth half-cycle.

Jeff Morse, PhD January 18, 2012 930
Flexible, Large Area Active Matrix Backplane Technology By Solution Cast Carbon Nanotube Thin Film Transistors

Flexible electronics are receiving significant attention for enabling a broad range of new applications and markets otherwise not possible with conventional silicon integrated circuit technology. Specifically in the areas of integrated electronics and sensors, thin-film transistors (TFTs) formed utilizing a range of nanomaterials now appear to be a viable competitor to more conventional TFT technologies such as amorphous silicon. The benefit of utilizing nanomaterials for active devices is the semiconducting properties of the specific nanomaterials. They can be optimized either during or after synthesis, then integrated into the thin-film device process sequence as a solution-based coating step. This enables the carrier transport properties of the nanomaterials to be optimized independently of device design and integration, and also provides a versatile means for adapting TFT circuit designs for flexible electronics applications. These include highly semiconductor enriched single wall carbon nanotubes (SWNTs) which are now being commercialized with >99% purity, and a range of semiconducting nanowire materials that have demonstrated charge mobility comparable to that of crystalline semiconductors. A key nanomanufacturing challenge is to maintain the performance of the individual nanoelements for the integrated system. As such ...

Jeff Morse, PhD January 12, 2012 824
Lead-Free Nanowire Piezoelectric Nanogenerator: Potential for Ubiquitous Power

Scavenging energy from the environment at meaningful power densities remains an elusive and costly target for a range of small-scale applications, such as wireless sensors and autonomous information networks. In addition, prospects for scaling such technologies to provide real energy production from renewable sources could be a driver, but require much more stringent cost and scaled manufacturing targets. Environmentally renewable sources of energy that scale from miniaturized power sources to large scale energy production include solar, thermal, and vibrational, all of which have been enhanced by the incorporation of nano-enabled materials and nanomanufacturing processes. In many scenarios, an ideal system might include each type of energy conversion device implemented in a thin stack with energy storage elements. As this vision gains momentum, optimization of each type of conversion element is still required, both from a materials and scaled fabrication standpoint. In the case of vibration energy scavenging, research on nanowire (NW) piezoelectric power generation has focused on the use of zinc oxide (ZnO) or ferroelectric materials (lead zirconate (PbZrO3), lead titanate (PbTiO3), barium titanate (BaTiO3)). Piezoelectric nanogenerators fabricated from these materials have demonstrated modest power densities, yet still have ch ...

Jeff Morse, PhD December 15, 2011 1015
Integrated Nanowire Logic Circuitry on Deformable Nonplanar Substrates

While a significant amount of recent research and development has focused on flexible electronics and improvements in thin film transistor performance on flexible substrates, less attention has been given to electronics application requiring deformable layouts or extreme, complex surface shapes and curvatures. As flexible electronics technology matures, a growing number of applications require stretchable or extreme nonplanar systems approaches. Examples of these applications include electronic eye cameras, hemispherical or curvilinear electronics, prosthetic or medical sensors, and stretchable LEDs, displays, photovoltaics, sensors, or logic devices utilizing thin silicon. In all of these applications it is critical to maintain the performance of the active electronic devices as the substrate is deformed due to changes in shape or external applied forces. A key issue related to this is the adjustment in resistive properties of nanomaterial-elastomer composites as the elastomeric substrates is stretched, thereby necessitating different approaches for the design and manufacture of deformable electronic systems.

Jeff Morse, PhD December 14, 2011 1499
Progress Towards High Yield, Large Area Graphene Suitable for Digital Nanoelectronics

Graphene has attracted significant interest for applications in nanoelectronics resulting in its unique properties that include near ballistic electronic transport and high carrier mobility at room temperature. These properties provide potentially superior performance for both high-frequency applications, as well as for digital nanoelectronics. While a primary issue for the latter has been the lack of a semiconductor bandgap, a necessary characteristic for switching the transistor on and off which is critical for digital electronics. This issue is being addressed through innovative approaches to demonstrate a graphene inverter technology, a key building block for graphene digital circuits. This technology also has the ability to produce large area, high quality graphene at relatively low cost. While techniques including epitaxial growth and chemical vapor deposition (CVD) are being demonstrated, they remain costly or exhibit limited quality. Techniques that produce single layer graphene sheets scalable to large areas are still required.

Jeff Morse, PhD November 16, 2011 759
Carbon Nanotube-Polymer Multilayer Structures for Light Weight, Enhanced Shock Absorbing Materials

Carbon nanotubes (CNTs) have demonstrated unique mechanical properties similar to those found in various fibrous materials, exhibiting excellent compression capability combined with extreme structural flexibility and recovery from mechanical deformation. As such, arrays or forests of vertically aligned CNTs have been considered for ultra-light weight shock absorbing material. In addition, CNTs incorporate multifunctional properties, including excellent electrical and thermal conductivity. These properties then allow layers formed for energy absorption to monitor in situ strain loading. The utilization of vertically oriented CNT arrays for mechanical energy absorbing benefits from fundamental understanding of stress wave mitigation ad deformation mechanisms in fiber reinforced composites or porous foam-like materials where layered structures of materials have been adopted for shock and vibrational damping. As weight reduction is an important feature of incorporating such materials having advanced multifunctional properties for practical impact protection, multilayer CNT arrays represent a viable candidate for such applications. For practical implementation, as-grown CNTs by chemical vapor deposition (CVD) tend to exhibit a softer base, and thus are more prone to buckling and deformation, making them excellent candidates for energ ...

Jeff Morse, PhD October 28, 2011 1293
Stabilized Nanostructure Composites for Nonvolatile Memory Device Applications

New approaches to nonvolatile memory devices have previously been demonstrated by charge trapping on metallic nanoparticles (NPs) embedded in organic layers. Devices based on this concept have shown that the memory capability of the device is affected by the distribution of the NPs. In the case of gold nanoparticles (AuNPs) that are frequently embedded in the organic layer or on the surface, the migration of the AuNPs during operation results in limited stability and device lifetime. Furthermore, the origin of the AuNP charging effects is not completely understood. One scheme to better stabilize the AuNPs while further ensuring effective charging conductive paths and simultaneously providing a barrier to discharging is the use immobilized AuNPs on semiconducting reduced graphene oxide (rGO) nanosheets.

Jeff Morse, PhD September 30, 2011 246
Solution-based Fabrication of Quantum Dot Light-emitting Diodes

Multilayer light emitting diode (LED) structures incorporating quantum-dot (QD) active layers have shown promise for lighting and display applications resulting from the efficient, narrow-band light emission provided by QD’s, along with the ability to tune emission wavelength through control of QD size. A limitation of QD-based LEDs has been the choice of materials used to facilitate the injection and transport of electrons to the active emission layer where recombination and subsequent light emission occurs. Materials used for the electron transport layer have previously used organic small molecules or metal oxides deposited by vacuum processes. While some of these materials have shown improvements in LED performance, they still exhibit limited performance for specific applications due to the poor charge transport properties of the electron transport layer. Furthermore, the vacuum processes used to fabricate the multilayer devices are limited in throughput for applications requiring high rate, large area processing to be economically competitive.

Jeff Morse, PhD September 07, 2011 959
Nanomaterials, Informatics Included in Food and Drug Administration’s Strategic Plan for Regulatory Science

Tasked with the core responsibility of protecting and promoting the health and safety of Americans through enhancing the availability of safe medical products and foods, the U.S. Food and Drug Administration (FDA) recently released a document titled Advancing Regulatory Science at FDA: A Strategic Plan. Central to FDA’s responsibilities is advancing the public health by expediting innovations that make foods safer and medicines and medical devices safer and more effective. In this capacity, the FDA must make decisions based on the best available scientific data, using the best tools and methods available in order to ensure products meet the highest quality standards for consumers. Concurrently, the FDA seeks to foster and advance innovation in the products it regulates, further noting in the document that rapid advances in innovative science have provided new technologies to discover, manufacture, and assess novel medical products, and to improve food safety and quality. As such, the strategic plan was developed to keep pace with these innovations and incorporate new scientific advances within the regulatory process, including developing new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of FDA-regulated products.

Jeff Morse, PhD August 31, 2011 703
Assessment of Dip Pen Nanolithography Processes for Nanomanufacturing Platforms

Dip pen nanolithography (DPN) has emerged as a versatile nanofabrication tool enabling the synthesis of nanoscale features via mass or energy transfer from an atomically sharp, inked tip to a substrate surface. Recently, Saha and Culpepper utilized DPN as a case study to evaluate and characterize key tip-based processes for nanomanufacturing, and subsequently how the process characterization can be used to identify the necessary control and system design parameters to achieve high throughput, high quality nanomanufacturing. This article presents an effective analysis of DPN nanomanufacturing process parameters which provides assessment of process limitations and considerations to be made prior to embarking a process scale-up. Such analysis enables critical assessment of the commercial viability of this emerging nanomanufacturing tool prior to investment for the production of value-added, nano-enabled technologies.

Jeff Morse, PhD August 17, 2011 543
Large Area Nanomanufacturing of Negative Index of Refraction Metamaterials

Optical metamaterials possess intriguing properties and have many potential applications including superlenses, resonators, cloaking, and others. Through design, negative-index metamaterials (NIMs) have electrical permittivity and magnetic permeability that are both negative, producing an overall index of refraction that is negative in some frequency range. Although many of the predicted properties have been experimentally demonstrated, economical fabrication has continued to be a challenge. In particular, 3D metamaterial structures have been very time-consuming to produce. 

Mark Tuominen, PhD August 10, 2011 495
Templated Synthesis of Nanostructured Materials by Sequential Infiltration

Nanostructured materials having well defined patterns over macroscopic length scales are of interest for a range of emerging applications in energy, sensing, nanomedicine, data storage, and electronics. Recently Peng et. al. have introduced a route to the formation of nanostructured materials by sequential infiltration synthesis (SIS). The SIS method uses BCP domains as a fixed template to control the nanofeatures of a range of materials by gas phase processes having controlled surface reactions similar to atomic layer deposition (ALD), a cyclic gas phase process for depositing thin films. 

Jeff Morse, PhD July 13, 2011 556
Hybrid Three-Dimensional Single-Walled Carbon Nanotube Architectures

Engineering of carbon nanotubes (CNT) into controlled morphologies and architectures has progressed to the point where electrodes fabricated from CNT networks have become viable candidates for applications such as flexible electronics, solar photovoltaics, and optoelectronics. Recently, Li et. al. reported on their investigation of forming organized 2D and 3D hybrid single-walled carbon nanotube (SWCNT)-polymer architectures. This paper reports a scalable approach to forming precisely controlled architectures of 3D SWCNT networks for integration of electrical connections. Nominally the approach would be adaptable to a wide range of metal and polymer substrates and could be further scaled down to smaller line width features as well as larger areas.   

Jeff Morse, PhD June 29, 2011 574
Precision Woven Fabric for Transparent Electrode Applications

Transparent electrodes represent an enabling technology for flexible electronics encompassing a range of product applications for both consumers and critical national needs, including displays, solar photovoltaics (PV), e-paper, and light emitting diodes (LEDs). Recently, Kylberg et. al. reported on the investigation of transparent, flexible electrodes based on a precision fabric using metallic and polymer fibers woven into a mesh configuration. In this paper, Transparent electrodes have been demonstrated using a precision woven mesh approach that enables subsequent integration of flexible electronic devices. The woven fabric mesh can be further optimized for conductivity and transparency through control of the metallic to polymer fiber ratios and spacing, and the follow-on polymer gap filling step. High rate scaled processing of these woven fabrics have already been demonstrated with roll-to-roll process speeds of 10 m/min achieved. Thus an ITO free transparent electrode approach has been demonstrated with the potential to impact future flexible electronics technology.

Jeff Morse, PhD June 08, 2011 849
Enhanced Performance in Graphene Transistors via Interface Engineering

As interest has grown in electronic devices and circuits fabricated from graphene thin films due to the large intrinsic carrier mobility, a key challenge remains to establish device integration strategies that enable field effect transistors (FETs) to have mobility approaching the intrinsic value. With thin film approaches to form graphene using chemical vapor deposition (CVD) on copper foils and subsequent transfer to silicon or other substrates for final integration, graphene has become a prime candidate for a range of applications in very large scale integrated (VLSI) circuits. Recently Liu et. al. have investigated the physics associated with the dielectric-graphene interface for integrated back gated FETs by controlling some of the detrimental scattering effects via application of self-assembled monolayers (SAM). Liu et. al. present a facile approach to improve the performance of scalable graphene transistors utilizing interfacial. The results provide valuable insights into the interfacial physics of graphene FETs. These results ultimately improve the potential application of graphene transistors towards VLSI circuits and applications.

Jeff Morse, PhD May 24, 2011 716
High Aspect Ratio Polymer Nanopore Membranes by Conformal Initiated Chemical Vapor Deposition

Recently, Asatekin and Gleason from MIT reported on their work using conformal initiated chemical vapor deposition (iCVD) to control the size and surface functionality of polymeric nanopores. Their work demonstrates a simple, scalable nanomanufacturing process to synthesize nanopore membranes for separation of small molecules. Utilizing a facile approach to tune the pore size, shape, and surface chemical properties, an approach to customize membrane properties for a range of separations applications has been developed. Additional models have been developed by the authors to better understand the conformal deposition processes for ultra-high aspect ratio nanopores. These models will be instrumental for further investigations of the range of monomers and initiators that can be used for the iCVD process.

Jeff Morse, PhD May 11, 2011 629
Improved High Frequency Performance and Scaling Effects of Graphene Transistors on Diamond-like Carbon

Graphene has attracted significant attention in recent years as a result of its high carrier mobility and saturation velocity, along with the ability to synthesize large-scale, high quality graphene sheets utilizing low-cost chemical vapor deposition (CVD) methods. Recently, Wu from IBM investigated the use of a diamond-like carbon (DLC) film grown on SiO2 as a substrate for transferring the graphene films.

Jeff Morse, PhD May 04, 2011 639
High Speed Water Sterilization Using One-Dimensional Nanostructures

Recently, Schoen et. al. investigated the incorporation of silver nanowires (AgNWs) and carbon nanotubes (CNTs) within a matrix of cotton, enabling a membrane with multiscale nanostructured materials to effectively inactivate  bacteria in water. This strategy takes advantage of the chemical and mechanical robustness of cotton as the support, along with the large pore structure between cotton fibers (tens to hundreds of microns), which, much greater than the length scale of bacteria, prevents physical clogging from occurring. In this paper, a novel approach to synthesize a textile based membrane architecture incorporating nanomaterials to enable specific functionality within the membrane has been reported. The fabrication approach is both simple and scalable, and provides effective inactivation of bacterial elements in a gravity fed filtration system.

Jeff Morse, PhD April 26, 2011 440
Bulk Metallic Glass Nanowires: A Platform for Electrochemical Applications

Carmo et. al. from Yale University recently reported on an approach to synthesize an electrode catalyst support using bulk metallic glass nanowires (BMGs). In this work, a top-down nanomanufacturing method is described to fabricate the Pt-BMG nanowire catalyst for electrochemical applications. The facile approach is scalable to large areas and further offers atomic level control over material composition and dispersion. Experimental results have indicated this approach may resolve key issues related to performance and durability for fuel cell applications, and may further impact additional energy generation and storage applications.

Jeff Morse, PhD April 20, 2011 681
Scalable Synthesis of Nanostructured Membranes for Solid-Oxide Fuel Cells and Electrolyzers

For solid-oxide fuel cell applications, high operating temperatures in excess of 700°C are necessary in order to attain sufficient oxygen-ion conductivity and reduce series resistance in the membrane in order to achieve reasonable power density. Further reducing the membrane thickness would possibly enable the operating temperature to be reduced, thereby relaxing the requirements for thermal insulation and management. Tsuchiya, et. al., describe a scalable method to integrate an ultra-thin SOFC membrane structure onto a silicon wafer support.

Jeff Morse, PhD April 06, 2011 590
Fabrication of Nanoscale Plasmonic Sensing Structures Over Large Areas

Plasmonic sensors provide a means of detecting chemical and biological species through the observation of spectral features by measurement techniques such as surface enhanced Raman spectroscopy (SERS) or surface plasmon resonance (SPR). In order to develop a full-scale plasmonic sensor, periodic nanostructures must be replicated over large-area surfaces, such as six-inch silicon wafers. By incorporating hybrid top-down and bottom-up synthesis, a versatile approach has been demonstrated for fabricating large-area plasmonic sensors. The ability to fine tune nanostructure features over large areas renders this technique highly adaptable, thereby opening up new opportunities for plasmonic sensor applications.

Jeff Morse, PhD March 29, 2011 618
Metallization of Branched DNA Origami Templates

 A simple and robust method for creating a wide variety of shapes and patterns, DNA origami can accommodate the increased complexity and flexibility needed for both the design and assembly of useful circuit templates. The next enabling step for circuit fabrication is the selective metallization of DNA origami templates in order to provide the conductive pathways for integrated nanoelectronics. Liu and colleagues provide improved understanding of and possible solutions to several key challenges for the metallization of DNA origami templates for nanoelectronic device fabrication.

Jeff Morse Ph.D March 15, 2011 675
Dielectrophoretic Alignment of High Density Carbon Nanotube Arrays

Methods to fabricate 2D arrays of densely packed SWNTs remain an active area of nanomanufacturing research. In this review, a solution-based, post-process has been reported employing AC dielectrophoresis assembly of ultrahigh density SWNT arrays. The versatile approach has demonstrated the highest linear packing density of aligned SWNTs reported to date, with potential impact on the manufacturing of future nanoelectronics.

Jeff Morse, PhD February 20, 2011 691
Engineered Graphene Molecular Building Blocks: Synthesis and Assembly of Controlled Superstructures

Typical graphene composite synthesis methods generate films with random orientation and positioning of the graphene nanostructures. However, there remains significant interest in exploring pathways to synthesize graphene superstructures with well-ordered and aligned architectures. In particular, vertically aligned graphene layer arrays (VAGLAs) could potentially enable a range of unique properties such as anisotropic thermal and electrical conductivity. Guo et al. demonstrate a process utilizing a range of CLC precursor molecules to synthesize vertically aligned graphene layer arrays with heights ranging from 50-800 nm with full 2D order.

Jeff Morse, Ph.D. February 16, 2011 744
Enhanced Efficiency Dye-Sensitized Solar Cells Utilizing Solution-Based Synthesis of Hierarchical Titanium Dioxide Nanotube Arrays

Recently, Zhuge et. al. reported on the use of ZnO nanowires as templates to form TiO2 nanotubes via a solution-based process wherein the ZnO nanowires are conformally coated with TiO2 and then selectively etched through a separate chemistry. With nanowires as a template, the authors synthesized a hierarchical double-shell architecture for the TiO2 nanotube in order to provide a highly mechanically stable, high electron conductivity structure on the core of the nanotube, with a high surface area amorphous material as the shell to enhance photoabsorption. 

Jeff Morse, Ph.D. February 04, 2011 1632
Hybrid Silicon/Carbon Nanotube Heterostructures for Reversible High-Capacity Lithium-Ion Anodes

A facile approach to synthesize hybrid Si-CNT nanocomposites suitable for Li+ battery anodes has been reported. While cycling stability remains an issue, the materials still show significant improvements over present anode materials systems in terms of reversible capacity and rate limitations.

Jeff Morse, Ph.D. January 26, 2011 1409
Precision Coatings Stabilize Metal Oxide Composites for Lithium Ion Battery Electrodes

Increasing the surface-to-volume ratio of the Lithium ion Battery electrode materials both increases the electrode contact area and reduces the Lithium ion (Li+) insertion distance, therefore modifying bulk or microscale metal oxide composites to nanometer-sized particles improves both the power and the capacity of the electrode material. The disadvantage of increased surface area for high voltage cathode materials includes undesirable side reactions such as the dissolution of the electrode material in the liquid electrolyte, resulting in degradation of capacity over charging cycles. Recently, Scott et. al. have investigated the use of atomic layer deposition (ALD) to coat metal oxide composite nanoparticles with an ultrathin layer to stabilize nanoparticles during charge/discharge cycling.

Jeff Morse, Ph.D January 19, 2011 918
Bulk Heterojunction Photovoltaics Utilizing Semiconducting Nanowires and Conjugated Polymers

Organic photovoltaics represent an attractive approach for the production of cost competitive solar cells, as they incorporate solution-based processes that are compatible with large-area, high-throughput manufacturing infrastructure. Enhanced device performance can be achieved incorporating organic/inorganic blends to form hybrid BHJ solar cells with improved electron mobility, dielectric constant, photon absorption, as well as enhanced physical and chemical stability. In this study, a solution-based method has been investigated to fabricate a new type of hybrid BHJ solar cell. By achieving self-alignment of semiconducting NW structures within the active layer, performance improvements were realized through enhanced carrier extraction pathways. 

Jeff Morse, PhD. January 05, 2011 683
Filling of Nanoporous Electrode Structures for Dye Sensitized Solar Cells by Initiated Chemical Vapor Deposition

Nejati and Lau investigate initiated chemical vapor deposition (iCVD) as a solvent-free method to form solid polymers in nanoscale structures, circumventing the challenges of replacing liquid electrolytes with solid state or gel materials in dye sensitized solar cells (DSSCs). 

Jeff Morse, PhD December 23, 2010 574
Replica Molding at the Subnanometer Scale Using Elastomeric Polymers

Replica molding of patterns having <10 nm features remains a significant nanomanufacturing challenge since the feature sizes at these length scales approach those of the monomers typically used for replication. In this investigation, Elhadj and colleagues demonstrate that polymers having an average radius of ~1 nm, average bond length of ~0.2 nm, and average distance between cross links of ~1 nm are capable of replicating vertical features from a solid substrate having dimensions significantly smaller than the average monomer size.

Jeff Morse, Ph.D December 15, 2010 407
Nanopatterned Silicon Membranes Provide Stable, Efficient Thermoelectric Properties

In order to realize competitive thermoelectric devices from silicon, an approach to synthesize high-density, highly uniform nanostructures must be utilized. Recently, Tang et. al. reported on the thermoelectric performance enhancements in a new type of nanostructured material, holey silicon (HS). In their approach, the authors demonstrate nanostructured silicon membranes that exhibit ~50 times reduction in thermal conductivity as compared to non-patterned membranes of the same thickness.

Jeff Morse, PhD. December 08, 2010 661
Functionalized Carbon Nanotube Electrodes for Increased Power Density in Lithium Ion Batteries

Applications such as electric vehicles and renewable energy sources require the development of materials combining advantages of both battery and electrochemical capacitor device technologies. Carbon nanotubes (CNT) have gained widespread attention for a range of electrochemical energy storage and conversion device applications given  their unique properties, including electrical conductivity, high surface area, and chemical and mechanical stability. Lee and colleagues investigated a new class of electrodes for energy storage devices facilitated by Li+ reactions with functional surface groups on the MWNT electrode structure. Combining this with a high surface area transition metal oxide lithium storage material at the opposing negative electrode, the authors have demonstrated unprecedented performance for energy storage device electrodes potentially impacting a range of hybrid applications.

Jeff Morse, PhD. November 24, 2010 525
Solid-State Polymer Nanocomposite Electrodes for Flexible, Ultrathin Supercapacitors

Emerging trends in energy storage device technologies for a range of consumer electronics, automotive, and grid-scale applications are targeting thin film materials conducive to flexible substrates. With the objectives of increased energy density, manufacturability, and flexibility, integration strategies for supercapacitor devices include carbon nanostructure composite electrodes with solid-state electrolytes. Utilizing CNT/PANI flexible electrode structures, Meng et. al. investigate the integration of an all-solid-state supercapacitor device structure utilizing a simple two-step approach.

Jeff Morse, PhD October 28, 2010 1324
Direct Imprint Patterning of Porous Nanomaterials

Synthesis of nanoporous structures utilizing more traditional fabrication routes typically incorporate lithographic patterning, followed by a wet or plasma etch step. Yet these processes are expensive and introduce complicating issues such as the infiltration of resist or thermoplastic materials within the pore network, which may alter the structure and is difficult to remove, as well as the challenge of retaining pattern fidelity during the etch step. For rapid, low-cost, large-area fabrication of patterned features and structures in nanoporous media, a facile, reproducible, direct printing process is required. Recently, Ryckman et. al. describe such a rapid, low-cost approach for patterning porous nanomaterials using a direct imprinting process that enables the capability to form complex networks and structures for a range of potential applications.

Jeff Morse, PhD. October 13, 2010 477
Aligned Carbon Nanotube Patterning Via Dry Contact Transfer Printing

Techniques to align CNT networks in-plane on a substrate have been investigated as a means to enable CNT-based electronic devices including transistors ad interconnects. One approach—transferring CNT thin films from one surface to another via a soft lithography—suffers from limited ability to achieve good adhesion of the CNT films to the transfer substrate and imprecise alignment of the CNT patterns. Ultimately, a transfer technique  that can be scaled to large area with high throughput processing at low temperature is required to achieve flexible substrates for many emerging display, lighting, and solar PV applications. Pint et. al. report a scalable means to create aligned CNT thin film patterns on both rigid and flexible substrates.

Jeff Morse, PhD. September 29, 2010 1216
Large Area NanoImprint Patterning by High-Resolution Epoxysilsesquioxane Resists

Ideally, nanomanufacturing processes that incorporate imprint patterning techniques would not need thermal cycling. To address this challenge, significant focus has been directed towards photocurable resist materials for NIL. One materials system that has received a good deal of attention are silsesquioxane (SSQ) polymers that have been developed as imprinting materials which can also be incorporated as functional patterns.The hurdles for these materials systems to achieve high-rate, large area patterning, include oxygen inhibition effects for methacrylate-based POSS and mold adhesion issues for POSS synthesized incorporating high content of epoxide groups. Pina-Hernandez and colleagues report a versatile method to control the materials properties of SSQ resins for high-rate, large area NIL patterning through straightforward chemical modifications.

Jeff Morse, PhD. September 22, 2010 419
Low Voltage Thin Film Transistor Circuits Printed on Plastic Substrates Using Aqueous Carbon Nanotube Inks

Integration of electronic circuits on flexible substrates is important for innovative displays, sensors, and electronic systems. Fabrication approaches commensurate with roll-to-roll and print process platforms will enable low cost, high throughput manufacturing to meet the targets associated with these emerging applications. Yet thin film transistor technologies typically suffer from low carrier mobility and  high switching voltages that limit the upper frequency at which the transistors can operate. Recently, Ha et. al. reported on digital circuits fabricated from CNT thin films printed on plastic and silicon dioxide substrates. In their approach, the combination of the high purity CNT films along with the high capacitance ion gel gate dielectric provides the low voltage, high speed circuitry performance in comparison to previous thin film transistor material and device designs.

Jeff Morse PhD September 08, 2010 527
Quantum Dots Precisely Placed by Controlled Flow

A key challenge for solution-synthesized nanostructures is to isolate a single particle with desired properties from solution and place it in the active region of a device structure. Ropp et al. present an alternative to optical tweezers and dielectrophoretic devices that uses controlled, electro-osmotic flow (EOF) to achieve nanometer precision placement of single quantum dots. The authors report control of individual ellipsoidal quantum dots as small as 6 nm x 3 nm.

J. Alexander Liddle August 24, 2010 349
Strategies for Integration of Directed Self-Assembly with Optical Lithography

Directed self-assembly (DSA) of nanoscale devices commonly combines self-assembling materials such as block copolymers (BCPs) with lithographically defined pre-patterned surfaces. To date, the most significant impact of DSA has been for the fabrication of nanoimprint master molds for bit-patterned magnetic storage media. Moving to semiconductor integrated circuit fabrication requires DSA strategies that adhere to the stringent requirements for wafer-scale integration and compatibility with semiconductor process techniques. Cheng et. al. demonstrate a straightforward approach to integrate DSA with either chemical or topographical pre-patterns using optical lithography and conventional 193 nm photoresists.

Jeff Morse, PhD August 18, 2010 1502
Understanding the Resistivity-Transparency Tradeoffs for Carbon Nanotube Electrodes on Flexible Substrates

A key remaining challenge for the preparation of CNT-based transparent electrodes suitable for flexible substrates is to optimize the sheet resistance and transparency of CNT films for specific implementations. Scardacci et. al. investigate the transmittance and sheet resistance tradeoff for CNT films spray-coated onto polyethylene terephtalate (PET) substrates and report a scalable method for the control of these parameters for transparent electrode applications.

Jeff Morse Ph.D July 30, 2010 803
Integrated Piezoelectric Nanowire Arrays: A Path for Energy Harvested Power

Present piezoelectric materials and devices show promise for niche power-harvesting applications, but their improved performance is necessary to achieve size, weight, and cost objectives in order to compete with existing energy sources. Xu et. al. report a facile approach to both vertical and laterally-oriented piezoelectric nanowire arrays for integrated piezoelectric devices.

Jeff Morse PhD. July 22, 2010 742
When Top-Down Meets Bottom-Up: EUV and X-ray Interference Lithography for Sub-20-nm Features

After achieving the 45-nm process [1], today's semiconductor industry is nearing the 20-nm process and looking for techniques that would enable sub-22-nm-half-pitch line patterns. EUV interference lithography (EUVIL) would advance the lithographic technology. EUVIL is capable of patterning sub-20-nm features at large scales and, unlike hexagonal sub-20-nm features demonstrated by block copolymer lithography, can create diverse geometries from line/space to hexagonal to rectangular array of dots. EUVIL and XIL are noted as some of the next generation lithography techniques that are under active development. Demonstrated applications of these techniques encompass production of catalyst arrays, nanophotonic devices, nanoimprint stamps, holographic fabricaion of Fresnel zone plates, guided self-assembly of block copolymers and colloidal particles, nanoparticle arrays, chemical patterning of self-assembled monolayers and radiation grafting of polymer nanostructures

Hyung Gyu Park June 30, 2010 417
Electrostatic Interactions for Bottom Up Assembly of Two-Dimensional Nanostructures

Stepanow et. al. reported on the fabrication of ordered 2D nanostructures in a solvent-free, high vacuum environment. In this work the authors selected several carboxylic acid groups and alkali metal atoms as the building blocks for supramolecular assembly. This approach potentially represents a facile, versatile method for the fabrication of highly ordered 2D nanostructures via a bottom up ionic assembly.

Jeff Morse, PhD June 14, 2010 314
Large Area Synthesis of Graphene Sheets by Metal-Catalyzed Crystallization

Zheng and colleagues describe a method to synthesize large-area, transferrable graphene films by metal-catalyzed crystallization of amorphous carbon (a-C) through thermal annealing. 

Jeff Morse, PhD. May 26, 2010 979
High Performance Rechargeable Batteries: Impacts of Nanostructured Materials Approaches

Yang et. al. describe a unique nanostructured rechargeable battery, wherein a lithium sulfide (Li2S)-mesoporous carbon cathode and silicon nanowire anode are combined to form a full cell. By incorporating the lithiated counterpart, Li2S, in the cathode, issues associated with elemental lithium anodes can be avoided while retaining the high capacity and performance offered by the silicon nanowire anode. This work provides an excellent example of the impact of nanostructured materials and emerging nanomanufacturing methodologies in extending the performance of specific materials systems for rechargeable battery applications.

Jeff Morse, PhD. May 20, 2010 935
Selective Synthesis of Horizontal Nanochannel and Nanowire Structures

Xiang and colleagues demonstrate a versatile approach to fabricate in-plane multi-contact nanowire structures on a single silicon chip. This approach may offer a versatile means to fabricate complex networks of nanowire materials, with the possibility of integration of field effect devices and sensors.

Jeff Morse, PhD May 14, 2010 407
Scalable Synthesis of Semiconducting Nanopatterned Graphene Materials

Kim and colleagues report on a method, using block copolymer (BCP) lithography, for achieving both the critical dimensions and scalability necessary for developing a semiconductor integration strategy for graphene-based devices. The relative ease by which BCP lithography can be implemented and scaled to large areas makes this a practical approach to large-area, commercializable applications for graphene-based electronics.

Jeff Morse, Ph.D April 30, 2010 785
Hierarchical Bottom-up Method for the Synthesis of High Performance Li-Ion Anodes

Magasinski and colleagues report a potentially versatile method for synthesizing complex, high surface area composite structures for Lithium-Ion battery anodes incorporating bottom-up and top-down methods.

Jeff Morse, Ph.D April 27, 2010 606
DNA Origami Used to Assemble Nanoplasmonic Structure

Ding et al. report on the use of deoxyribonucleic acid (DNA) origami as a scaffold for the assembly of gold nanoparticles into a carefully organized structure to create, ideally, a device with a strongly enhanced plasmonic resonance.

J. Alexander Liddle April 09, 2010 746
Nanopatterned Polymer Photovoltaic Heterojunction Using a Double Imprint Process

Polymer bulk heterojunction materials offer a potentially low-cost, facile approach for the fabrication of efficient photovoltaic (PV) devices. He investigate the use of nanoimprint lithography (NIL) as a method to form patterned polymer blends generating a three-dimensional interpenetrating hierarchy of electron donor and acceptor materials.

Jeff Morse, PhD. March 30, 2010 567
Polymeric Nanomaterials for High Efficiency Energy Harvesting and Conversion

Incorporating the advantages of high conversion efficiency, scalable manufacturing, and facile integration strategies, PVDF nanofiber power generators provide the basis for self-powered textiles, embedded power sources for nanodevices and wireless sensors, and large area fabrics for portable electronics implementations.

Jeff Morse, Ph.D March 16, 2010 1893
Two Approaches to Large-Area Graphene Synthesis For Device Quality Materials

Li and Hofrichter offer two approaches for large-area synthesis of graphene on substrates with potential for device integration. 

Jeff Morse, Ph.D February 26, 2010 6160
Thermal Dip Pen Nanolithography for Direct Writing of Polymer-NanoParticle Composites

Lee et. al. demonstrated a maskless, additive approach for direct writing of a range of NP–polymer compositions using thermal dip-pen nanolithography (tDPN). This technique represents a facile strategy for deposition of a wide range of NP composite materials in order to create dense nanopatterned films.

Jeff Morse, Ph.D February 23, 2010 3921
Implications of Supramolecular Templating of Thick Mesoporous Titania Films for Dye-Sensitized Solar Cells

Zhang, reported on an approach to synthesize thick mesoporous inorganic oxide films in order to harvest more  incident solar radiation, thereby enhancing the efficiency of the solar cell.

Jeff Morse, PhD. February 11, 2010 4307
Nanostructured Solar Cells Have Improved Charge Collection and Self Cleaning Properties

Zhu, et. al., report on the use of “nanodome” solar cells to simultaneously improve optical absorption and enhance surface cleanliness. The resulting structures have power conversion efficiencies of 5.9%.

Fred Sharifi February 08, 2010 6162
Metal-Catalyst-Free CVD Synthesis of Single Wall Carbon Nanotubes

There are several advantages to metal-catalyst-free Carbon nanotubes, from use in a broader range of applications to easier purification, mitigated toxicity concerns, and lower prices of pure CNT materials. Synthesis of single wall carbon nanotubes (SWNT) on non-metallic catalysts, as recently carried out by Liu B. et al. and Huang S. et al., demonstrates that one could generalize standard synthesis processes to capture the fundamental physics underlying the CNT nucleation and growth.

Hyung Gyu Park January 25, 2010 7074
Controlled Deposition of Microparticle Arrays for LEDs

Kumnorkaew and Gilchrist report on the use of the “coffee stain” effect to simultaneously deposit controlled arrays of  microparticles embedded in nanoparticles.  These structures can dramatically improve the output coupling of III-Nitride LEDs.

J. Alexander Liddle December 29, 2009 1544
Nanomaterial Enabled Conductive Paper: A New Paradigm for Flexible Electronics and Energy Storage

While nanostructured materials combined with emerging nanomanufacturing processes are advancing the next generation of displays, e-paper, renewable energy, and energy storage devices, the predominant technologies have employed scaled processes on flexible substrates facilitated by roll-to-roll platforms. Recently, a group of researchers at Stanford University have taken this concept one step further by demonstrating the core materials and processes for fabrication of such devices on everyday paper.

Jeff Morse, PhD. December 15, 2009 1457
Integration of CdSe Nanostructures on Graphene Basal Plane by Electrochemical Deposition

Electrochemical deposition techniques offer an alternative method for grafting nanostructured materials on a graphene surface. Kim et. al. report an innovative approach to directly integrate CdSe quantum confined nanostructures with graphene basal planes.

Jeff Morse, PhD. December 09, 2009 1417
Organic Electrophoretic Inks Utilizing Encapsulated-Dye Nanoparticles

Oh and collegaues report a straightforward synthesis route for manufacturing colored electrophoretic inks for emerging flexible displays and E-paper applications.

Jeff Morse, PhD. November 30, 2009 1048
Nanoparticle-Polymer Array-Based Sensors for Biomedical Applications

Distinguishing between normal, cancerous, and metastatic cells is a major hurdle for the early detection of cancer. Bajaj, et. al. describe a detection approach based on selective noncovalent interactions between cell surface elements and functionalized nanoparticle sensors that does not require a priori knowledge of specific biomarkers.

Jeff Morse, PhD November 02, 2009 1162
Study of Chinese Print Workers Claims to Provide the First Human Evidence of the Clinical Toxicity of Long-term Nanoparticle Exposures

A recent study published in the well-known medical journal, the European Respiratory Journal, has been receiving significant publicity as the authors have claimed their findings support an apparent linkage between workplace exposures to nanoparticles and severe respiratory disease.  Specifically, in this study, investigators at China's Capital University of Medical Science related unusual and progressive lung disease in seven Chinese workers, two of whom died, to nanoparticle exposures in a print plant where a polyacrylic ester paste containing nanoparticles was used.  This linkage was made by the study investigators despite a general lack of exposure data for the workers. 

Christopher M. Long and Barbara D. Beck October 29, 2009 1681
Pressure Induced Microphase Separation of Block Copolymers for Ultrahigh-Density Data Storage

Jo et. al. introduce a novel concept for the formation of nanopatterns on a polymer film at room temperature.

Jeff Morse, PhD October 21, 2009 1091
Self-assembled Artificial DNA Nanostructures on Templated Surfaces

Kershner, et. al., report a synergistic top down and bottom up process for creating self-assembled nanostructures of DNA origami.

Jeff Morse, PhD October 16, 2009 1150
Dynamic Patterning of Nanostructures by Combined Electrokinetic Forces

NanoPen represents a versatile approach to patterning a range of nanostructured materials, including nanorods and nanotubes.

Jeff Morse, PhD October 14, 2009 973
Benefits of Three-Dimensional Integrated Nanostructures for Energy Applications

In three new studies, the ability to design 3D materials architectures provides a versatile approach towards optimization of device properties for enhanced performance in product applications.

Jeff Morse, Ph.D September 15, 2009 1460
Nanostructured Cathodes for Improved Energy Storage in Rechargeable Batteries

Ji et. al. investigate the use of nanostructured sulphur/mesoporous carbon as a cathode material to overcome the challenges of Lithium-Sulfur cell technology, suggesting a path to the realization of high-capacity, long-cycle-life rechargeable batteries.

Jeff Morse, Ph.D August 21, 2009 1365
Enhanced Solar Cell Efficiency Using Nanoimprinted Surface Morphology

Lee et. al demonstrate a simple, low-cost method to imprint nanoscale patterns in the surface of polymer-based photovoltaic materials systems for enhanced power conversion efficiency.

Jeff Morse, Ph.D August 13, 2009 1449
Subdiffraction-limited Imaging and Lithography Using Flat HyperLens Designs

Xiong et. al. report a feasible design to achieve subdiffraction-limited patterns generated from a diffraction-limited mask using a hyperlens with flat input and output surfaces. This approach has demonstrated utility for generating arbitrary subdiffraction-limited pattern features.

Jeff Morse, Ph.D August 10, 2009 1350
Progress Towards High-Throughput Continuous Nanoimprinting

Progress towards scaled, large-area NIL for high-throughput roll-to-roll and roll-to-plate processes has been demonstrated, representing a significant step towards integration of emerging nanomanufacturing techniques with high throughput production infrastructure.

Jeff Morse, Ph.D July 17, 2009 1849
Novel One-Pot Synthesis of Thiol-group Modified Silicate Nanoparticles

Neville, et. al., investigate a silicate nanoparticle fabrication process based on natural biosilication, in which specialized proteins catalyze silication at neutral pH and ambient temperature conditions to produce silicate nanostructures down to 50 nm in size.

Jeff Morse, Ph.D. July 16, 2009 1476
Aerosol Synthesis of Carbon Nanotube Networks for Thin Film Transistors

Zavodchikova, et. al., report an alternative technique for the fabrication of CNT networks which provides several benefits, including the use of lower heat tolerant substrates, the elimination of potential contaminants from the CNT suspension medium, and the use of standard photolithography and liftoff processes enabling high precision patterning of CNTs for TFT channels. Initial results of their CNT network-based TFT devices demonstrate competitive performance.

Jeff Morse, Ph.D. July 10, 2009 1416
Organometallic Resists for Improved Pattern Transfer by Nanoimprint Lithography

Acikgoz, et. al., reported on their investigation of organometallic polymers as a means to enhance the etch resistivity of NIL resists for pattern transfer. A high molar mass PFMPS resist exhibited high fidelity pattern transfer over 2 cm x 2 cm areas.

Jeff Morse, Ph.D. July 02, 2009 950
Three Dimensional Titania Nanonetworks for Electrochemical Applications

A straightforward, scalable approach has been demonstrated to create a more efficient 3-D nanostructured electrode material for electrochemical applications. The method incorporates an innovative biotemplating approach with a top-down conformal coating process to realize an operationally beneficial nanonetwork structure. 

Jeff Morse, Ph.D June 23, 2009 1220
Functional Self Assembly Incorporating Quantum Dot-Block Copolymer Hybrids

Zorn,, describe a hybrid Quantum Dot-Block Copolymer system for LEDs that exhibits the excellent optical properties of the QD materials and maintains the processability of BCP systems. 

Jeff Morse, Ph.D June 18, 2009 1357
The Challenges of Nanomanufacturing for Energy Storage Devices

Baberjee, et. al., report on a combined fabrication process for nanotubular MIM capacitor arrays that enable very high levels of uniformity in a regular nanopatterned configuration and is reproducible using well established equipment and procedures.  

Jeff Morse, Ph.D. May 26, 2009 1215
Massive Replication of Nanoscale Surface Features Using Amorphous Metals

Kumar, et. al., report a unique approach to the formation of nanoscale features of amorphous metals. This process incorporates relatively simple embossing techniques to realize massively replicated surface structures having <100nm dimensions.  

Jeff Morse, Ph.D. May 12, 2009 1436
Carbon Nanotube Sheets for Artificial Muscles

Aliev et. al. describe an investigation of carbon nanotube aerogels exhibiting giant-stroke, superelastic properties. Their aerogel sheets exhibit behavior similar to low-modulus rubbers when stretched in sheet width direction by factors up to 300% thereby making this material an ideal candidate for large stroke actuation. 

Jeff Morse, Ph.D April 28, 2009 1949
Cytotoxicity and Genotoxicity of Silver Nanoparticles in Human Cells

This study proposes the mechanism of toxicity of starch coated silver nanoparticles in human lung and brain tumor cells is through disruption of the mitochondria, the main source of energy for the cell.  Starch was previously shown to make the nanoparticle soluble in water and to protect the nanoparticles from “clumping” in the water or within the cells. An exposure to nanosilver may lead to a decrease in metabolism at the cellular level. Further investigation is needed to determine if silver nanoparticles are safe for biological and medical applications.  

Christie M. Sayes and Vanessa De La Rosa April 28, 2009 2435
Controlled Ultrathin Films of Carbon Nanotubes for Electrochemical Applications

Lee and colleagues report a process to incorporate functionalized multi-wall carbon nanotubes into highly tunable thin films using Layer-by-layer assembly.    

Jeff Morse, Ph.D April 09, 2009 1500
Wafer-scale Fabrication of CMOS Logic by Aligned Arrays of Single-wall Carbon Nanotubes

Ryu and colleagues report the fabrication of SWNT integrated circuits over a large area (4” wafer) and with superior performance using a horizontal array of aligned, non-overlapping nanotubes with lithographically patterned electrical contacts for a group of nanotubes.  

Sonia Grego, Ph.D March 16, 2009 1597
Direct Printing of Aligned Carbon Nanotubes by Pattern Transfer

With a relatively simple technique, Im and colleagues  demonstrate the preparation of aligned single wall CNTs over large surface areas.  

Jeff Morse, Ph.D. March 13, 2009 1235
Hybrid Solar Cells with Potential for Large-scale Manufacture

Kortshagen et al describe a hybrid photovoltaic cell that is ideally suited for inexpensive, large-scale manufacture, offers an alternate material platform that does not contain heavy metals, and delivers an incident photon-to-current efficiency (IPCE) of 1.15%. 

Katherine Rice March 12, 2009 1519
Dielectrophoretic Assembly of Graphene Nanostructures

Burg, et. al., demonstrate a controllable and reliable method for the scalable, high-yield directed assembly of ultrathin graphene sheets. 

Jeff Morse, Ph.D. February 27, 2009 1875
Co-Electrodeposition of Functionalized Carbon Nanotube/Chitosan Composites

Jia, et. al., describe the co-electrodeposition of an adherent CNT composite coating with enhanced mechanical properties transferred to a macrostructure. This is, perhaps, the first time a significant enhancement in the intrinsic strength of a macrostructure has been reported for an additive coating incorporating cross-linked nanocomposites.  

Jeff Morse, Ph.D. February 20, 2009 2037
Fast, Efficient Layer-by-Layer Assembly Method

Merrill and Sun describe a new method for achieving multilayered nanolamina,  called spin-spray layer-by-layer self-assembly (SSLbL), which significantly increases the efficiency of traditional LbL assembly techniques. 

Jeff Morse, Ph.D. February 12, 2009 1781
Synthesis of Hybrid Coaxial Nanotubes for Lithium Batteries

Reddy et. al. recently report the synthesis and electrochemical testing of hybrid coaxial MnO2/Carbon Nanotube array electrodes for lithium battery applications. With the high aspect ratio of the hybrid nanotube configuration and the ultra-high surface area associated with the entire array, the potential exists to engineer the battery electrodes for long life while significantly enhancing the Li storage capacity.  

Jeff Morse, Ph.D. February 12, 2009 1749
Nanocrystal Synthesis by Seeded Growth

New studies have improved the understanding of the role of seeds in solution-phase growth of nanocrystals with complex structures and materials compositions.  

Jeff Morse, Ph.D. February 06, 2009 1440
Template Guided Fluidic Assembly Process Mechanisms Characterized

Jaber-Ansari and colleagues characterize the role of surface properties for the assembly and control of SWNT architectures providing a potential basis for wafer-scale manufacturing of SWNTs for a range of emerging devices, systems, and applications.  

Jeff Morse, Ph.D. January 30, 2009 1638
Large Scale Production Technique for Functionalized Carbon Nanotubes

Gao, et. al., report a versatile, one-step process technology for producing f-CNTs based on nitrene chemistry. 

Jeff Morse, Ph.D. January 28, 2009 1607
Low-temperature Growth of Patterned ZnO Nanowire Arrays

 Xu, et al. demonstrate the low-temperature (<100 °C) growth of size-controlled, patterned ZnO nanowire arrays onto multiple types of substrates. 

Aaron Saunders, PhD. January 28, 2009 1477
Large Scale Methodology for Preparation of Carbon Supported Metallic Nanoparticles

Silver and other metallic nanoparticles are of significant research interest due to their intriguing properties for applications in optoelectronics, catalysts and fuel cells, and antimicrobial surfaces. Wang, et. al., offer a scalable approach to forming supported metallic nanoparticle compositions through a straightforward manufacturing process. 

Jeff Morse, Ph.D. January 22, 2009 1263
Gram-scale Production of Graphene

Choucair et al., report a bottom-up chemical method to directly synthesize graphene sheets in gram quantities. This technique is based on the laboratory reagents ethanol and sodium, which are reacted to give an intermediate solid that is then pyrolized, yielding a fused array of graphene sheets that can be dispersed subsequently by mild sonication and dried to produce graphene powder. 

Mark Tuominen, Ph.D. January 21, 2009 2493
Unique Clot Forming Materials via Self-Assembled Fibrin NanoSheets

O’Brien,, have demonstrated the self-assembly of molecularly thin, continuous fibrin sheets in situ from physiologic buffers having normal pH and ionic strength. The naturally occurring fibrin polymerization, and subsequent ability to self-associate to form extended 2-D molecular scale sheets, represents a new class of biological membrane. 

Jeff Morse, PhD January 15, 2009 1239
Pilot study on mice reports asbestos-like pathogenicity of carbon nanotubes

This study evaluates the effects of an intraperitoneal (i.p.) injection of four preparations of MWCNT compared to i.p. injections of long-fibre mosite (LFA) and short-fibre amosite (SFA) in mice. Results showed clear differences between long and short/tangled MWNTs.  

Annette Santamaria, Ph.D. January 15, 2009 1229
Controlled Nanomanufacturing of Magnetic Composite Nanofibers

Santala,, report a versatile method for preparing magnetic and photocatalytic nanofibers by combining electrospinning and atomic layer deposition (ALD) to control both the materials composition of the nanofiber and the specific structure and dimensions of the resulting fibers.  

Jeff Morse, PhD. January 07, 2009 1753
Large Area Printed Transfer of Aligned Carbon Nanotubes for Transparent Electronics Applications

In an ACS Nano Article ASAP for December, Ishikawa and colleagues report several remarkable results associated with the use of aligned single wall carbon nanotubes to create transparent thin film transistor arrays. 

Jeff Morse, PhD. December 19, 2008 1319
Self-Assembled Nanoparticle Superlattices by Moulded Microdroplet Techniques

Cheng,, demonstrate a new superlattice patterning methodology that shows promise for specific patterns and shapes in two and three dimensional configurations.  

Jeff Morse, PhD. December 16, 2008 1382
Enhanced Mass Transport in Carbon Nanotubes

Researchers experimentally demonstrate fast mass transport through a specially fabricated, sub-2-nanometer carbon nanotube filter.  

Haitao Liu, PhD. December 01, 2008 1329
Directed Assembly of Carbon Nanotubes: Facilitating Seamless Integration with Future Generation Nanoelectronics

Researchers at Northeastern University report a scalable method for directed assembly of single-wall carbon nanotubes at ambient temperatures for application with integrated circuits.  

Jeff Morse, PhD. November 12, 2008 1469
A new chemical route to synthesize Cu-Ni alloy nanostructured particles

Cangiano et. al. demonstrate the viability of producing Cu–Ni alloy nanoparticles of homogeneous composition via a four-step, citrate-gel process with significantly reduced reaction temperatures.  

Lingyan Wang, PhD. November 10, 2008 1913
Nanomanufacturing for Fuel Cells Utilizing Self-Assembly Techniques

A recent paper by Taylor,, reports the performance of polymer electrolyte membrane (PEM) fuel cell membrane electrode assemblies (MEAs) synthesized using layer-by-layer electrostatic self-assembly techniques that improve Pt utilization by approximately a factor of 4 in comparison to conventional MEA fabrication methods.  

Jeff Morse October 09, 2008 2062
A Simple Method for Forming Hybrid Core-Shell Nanoparticles Suspended in Water

Jean-Christophe Daigle and Jerome P. Claverie report a method for fabricating materials composed of inorganic nanoparticles encased in organic polymer shells.   

Michael Steigerwald, Ph.D. September 30, 2008 2168
Nanostructured Microspheres Produced by Supercritical Fluids Extraction

A recent paper addresses two major challenges in drug formulation: drug solubility and sustained release for greater therapeutic effectiveness, reduction of side effects, and improvement of patient’s comfort and compliance.  

Carl D. Saquing, Ph.D. September 30, 2008 1838
Development of a Metal Containing Glass Hollow Fiber Drawing Technique For The Production of Extremely Long Micro/Nanowires

Zhang et al. report a novel fiber drawing method for forming very long metallic wires with micron to nanometer sized diameters.  This method is amenable to scale up for producing vertically aligned arrays of these micro/nanowires in large quantities.   

Douglas E. Betts, Ph.D. September 30, 2008 1529
Nanoparticle Synthesis: Reduced Agglomeration through Electric-Field Enhanced Flame Synthesis

Reporting in Journal of Nanoparticle Research, Zhao and colleagues describe a technique to model charged species behavior by electrostatic manipulation that provides additional time/temperature histories beyond flow transport measurements.  

James Krajewski September 16, 2008 1816
Advances in Aerosol Processing Furthering the Utilization of Aerosols in Nanomanufacturing

In a recent research review paper, Professor Steven Girshick from the University of Minnesota details several advances in aerosol processing that can further the utilization of aerosols in nanomanufacturing. 

Michele Ostraat, Ph.D. September 16, 2008 1344
Functionalized Silica Nanoparticles Using Electrostatic Suspension Stabilization: Next Generation Biodegrading and Imaging Agents

Reporting in Journal of Nanomaterials, Bergman and colleagues described a method to make fluorescent dye functionalized silica nanoparticles with a series of surface functionalization steps, and established the relationship between particle suspension stability with surface functional group of the particles that were prepared.  

Li Han, Ph.D. September 15, 2008 5015
BioMimic Fabrication of Electrospun Nanofibers with High-throughput

He et al., reported on a novel means to reduce surface tension by electrospinning from the wall of a bubble as opposed to a droplet. 

Anthony Andrady, Ph.D. September 12, 2008 1675
Improved Control of Microfluidic Nanocrystal Production

Winterton et al. reported a new microfluidic reactor design that could potentially maintain several different temperature zones within a single chip.  

Haitao Liu, Ph.D. September 10, 2008 1204
Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerization of Aniline and Pyrrole

Nadagouda et al. reported a simple, green synthetic approach of Ag and Pd nanospheres, nanowires, and nanorods using Vitamin B2 and investigated the catalytic activities of these nanomaterials. 

Xaiomu Wu, Ph.D. September 10, 2008 3252
Induction of mesothelioma in p53+/- mouse by intraperitoneal application of multi-wall carbon nanotubes

This study reported that p53 heterozygous mice developed and died from peritoneal mesothelioma approximately 144 days following a single intraperitoneal injection of multiwalled carbon nanotubes (MWCNT) but not after treatment with fullerenes. The authors concluded that it would be prudent to implement strategies to keep good control of exposure to fibrous or rod-shaped carbon materials in the workplace until the biological properties and carcinogenic potential are fully assessed.  However, it is important to note that the route of administration was intraperitoneal and not inhalation and the mouse model used is susceptible to the development of tumors. 

Annette Santamaria, Ph.D, DABT September 09, 2008 1469
The Frontline of Nanomanufacturing: Top Down Meets Bottom Up for Patterned Media Approaches to Magnetic Data Storage

The ability to create features using directed self-assembly from pre-patterned templates, as reported in two recent Science papers, may further address the needs of the integrated circuit industry for specific design approaches.  

Jeff Morse September 04, 2008 1422
Large-scale Fabrication of Nanowire Devices

Semiconductor nanowires (NW) are expected to play a critical role in future electronic and optoelectronic devices as an approach to sustain the scaling trends in electronics and to provide crucial performance enhancements, such as adding photonic functionalities to silicon platforms. 

Sonia Grego, Ph.D. September 03, 2008 1758
Directed Self-Assembly of Block Copolymers for Nanolithography: Transcending Next Generation Integrated Circuit Nanomanufacturing Processes

Stoykovich, et al. present results of incorporating directed self-assembly of BCPs for the fabrication of isolated features, and critical IC geometries.  

Jeff Morse July 02, 2008 1484
A Window of Opportunity: Designing Carbon Nanomaterials for Environmental Safety and Health

The nanotechnology movement has been given a unique "window of opportunity" to systematically investigate the toxicity of nanotechnology products and to develop ways to manage health risks before large scale manufacturing becomes widespread.  

Christine M. Sayes, Ph.D. April 30, 2008 1457
Exposure to Diesel Exhaust Induces Changes in EEG in Human Volunteers

This study examines changes in brain activity, particularly in the frontal cortex, that result from exposure to diesel exhaust (DE), which is a mixture of non-engineered nanoparticles and exhaust compounds.  Further human studies are necessary to determine whether nanoparticles in DE are responsible for these effects and if so, by what mechanism.  

Linda Cohen, MPH April 23, 2008 1249
Considerations on Occupational Medical Surveillance in Employees Handling Nanoparticles

The authors discuss the appropriateness of establishing occupational medical surveillance programs for workers handling nanomaterials. Because there is no information yet available on health outcomes that may be associated with exposure to nanoparticles, the authors suggest general medical screening, baseline examinations, and establishment of exposure registries to document who is currently working with nanomaterials. 

Diane J. Mundt, Ph.D. November 02, 2007 1726
Persistent Tissue Kinetics and Redistribution of Nanoparticles, Quantum Dot 705, in Mice

The findings from this study indicate that following intravenous injection in mice, quantum dots may localize in important organs such as the kidney or liver, and they have a very long biological half-life. Such observations are important, given the potential for the use of quantum dots for biological imaging purposes in humans. 

Annette Santamaria, Ph.D, DABT September 07, 2007 1554
Assessing Toxicity of Fine and Nanoparticles

This study indicates that the observed in vitro effects of nanoparticles are not necessarily predictive of in vivo pulmonary effects.  In vitro assays will need to be standardized and validated relative to in vivo effects before they can provide useful screening data on the relative toxicity of inhaled nanoparticles. 

Annette Santamaria, Ph.D, DABT September 07, 2007 1919
Nanomaterial Health Effects

It is uncertain if engineered nanomaterials may be toxic to cells and organisms, due to their extremely small nature (Less than 100 nanometers); therefore, it is necessary to develop and implement relevant regulations for public health policy. 

Aimee O'Sullivan, MPH August 24, 2007 2573
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