National Nanomanufacturing Network

3D printed nanostructures made entirely of graphene

National Nanomanufacturing Network - December 12, 2014 - 3:49am
Graphene has received a great deal of attention for its promising potential applications in electronics, biomedical and energy storage devices, sensors and other cutting-edge technological fields, mainly because of its fascinating properties such as an extremely high electron mobility, a good thermal conductivity and a high elasticity.The successful implementation of graphene-based devices invariably requires the precise patterning of graphene sheets at both the micrometer and nanometer scale. Finding the ideal technique to achieve the desired graphene patterning remains a major challenge. 3D printing, also known as additive manufacturing, is becoming a viable alternative to conventional manufacturing processes in an increasing number of applications ranging from children toys to cars, fashion, architecture, military, biomedical science, and aerospace, to name a few. For the first time, researchers have now demonstrated 3D printed nanostructures composed entirely of graphene using a new 3D printing technique. The research team, led by Professor Seung Kwon Seol from Korea Electrotechnology Research Institute (KERI), has published their findings in the November 13, 2014 online edition of Advanced Materials ("3D Printing of Reduced Graphene Oxide Nanowires" (http://dx.doi.org/doi:10.1002/adma.201404380)) "We developed a nanoscale 3D printing approach that exploits a size-controllable liquid meniscus to fabricate 3D reduced graphene oxide (rGO) nanowires," Seol explains. "Different from typical 3D printing approaches which use filaments or powders as printing materials, our method uses the stretched liquid meniscus of ink. This enables us to realize finer printed structures than a nozzle aperture, resulting in the manufacturing of nanotructures." The researchers note that their novel solution-based approach is quite effective in 3D printing of graphene nanostructures as well as in multiple-materials 3D nanoprinting. "We are convinced that this approach will present a new paradigm for implementing 3D patterns in printed electronics," says Seol. For their technique, the team grew graphene oxide (GO) wires at room temperature using the meniscus formed at the tip of a micropipette filled with a colloidal dispersion of GO sheets, then reduced it by thermal or chemical treatment (with hydrazine). The deposition of GO was obtained by pulling the micropipette as the solvent rapidly evaporated, thus enabling the growth of GO wires. The researchers were able to accurately control the radius of the rGO wires by tuning the pulling rate of the pipette; they managed to reach a minimum value of ca. 150 nm. Using this technique, they were able to produce arrays of different freestanding rGO architectures, grown directly at chosen sites and in different directions: straight wires, bridges, suspended junctions, and woven structures. "So far, to the best of our knowledge, nobody has reported 3D printed nanostructures composed entirely of graphene," says Seol. "Several results reported the 3D printing (millimeter- or centimeter-scale) of graphene or carbon nanotube/plastic composite materials by using a conventional 3D printer. In such composite system, the graphene (or CNT) plays an important role for improving the properties of plastic materials currently used in 3D printers. However, the plastic materials used for producing the composite structures deteriorate the intrinsic properties of graphene (or CNT)." He points out that this 3D nanoprinting approach can be used for manufacturing 2D patterns and 3D architectures in diverse devices such as printed circuit boards, transistors, light emitting devices, solar cells, sensors and so on. Reducing the 3D printable size to below 10 nm and increasing the production yield still remain challenges, though. Source: Nanowerk (http://www.nanowerk.com/spotlight/spotid=38253.php)

Inviting articles: Special issue on Nanoinformatics (Beilstein Journal of Nanotechnology)

National Nanomanufacturing Network - December 12, 2014 - 3:16am
The Beilstein Journal of Nanotechnology (BJNANO, http://www.beilstein-journals.org/bjnano (http://www.beilstein-journals.org/bjnano)) invites you to submit papers on any aspect of Nanoinformatics to a Thematic Issue of BJNANO. BJNANO is a High Impact (SCI: 2.3) Open Access journal with No Publication Fees in the broad areas of Nanosciences and Nanotechnology. The BJNANO Thematic issue on Nanoinformatics will include, but are not limited to, the following topics: Data management and database development for nanomaterialsOntology and meta-data design for nanomaterial data Nanomaterial data standards and interoperation/sharing protocols Nanomaterial characterization (i.e., physicochemical/structural properties) Text/Literature mining for nanomaterial data collection and integrationAnalysis/Quantification for nano-images (e.g., TEM images of nanomaterials, images generated from in-vivo high-throughput screening of nano-bioactivity)Assessment of the value of information in nanomaterial dataData mining/Machine learning for nanomaterial data, particularly the development of (quantitative) structure-activity relationships for nanomaterialsSimulation for nanomaterial fate transport, nano-bio interactionsComputing applications for nanomedicine (e.g., drug delivery systems (nano-excipient), diagnosis and prevention, and safe disposal of nanomedicine as household goods)Visualization of nanomaterials dataEnvironmental and health risk assessment, life-cycle analysis, and regulatory decision making for nanomaterialsAssessment of ethical and social issues of nanotechnologyInfrastructure (frameworks/software/tools/resources) for nanoinformatics If you're interested in submitting papers to the thematic issue on Nanoinformtics, the deadline for the submission is: March 31, 2015. Submission instructions can be found at: http://www.beilstein-journals.org/bjnano/submission/submissionOverview.htm (http://www.beilstein-journals.org/bjnano/submission/submissionOverview.htm). When submitting, please also indicate in your cover letter that your paper is submitted for consideration by the thematic issue on Nanoinformatics. For further information regarding the thematic issue on nanoinformatics please contact Dr. Rong Liu (rliu.pro@gmail.com (mailto:rliu.pro@gmail.com)).

Registration Open for 2015 Nanoinformatics Workshop

National Nanomanufacturing Network - December 8, 2014 - 4:31am
Nanoinformatics Workshop: Enabling successful discovery and applications January 26-28, 2015Holiday Inn National Airport Hotel Arlington, VA REGISTER FOR THE WORKSHOP TODAY (https://umass.irisregistration.com/Auth/Authenticate/Index?ReturnUrl=%2fRegister%3fcode%3dNanoinformatics code=Nanoinformatics) Regular attendees: $200, Students: FREE Registration for the Nanoinformatics 2015 workshop (http://nanoinformatics.org/2015/overview) is now available. Registration is open until January 16, 2015, but please note that discounted hotel reservations (http://nanoinformatics.org/2015/venue) have a December 29, 2014 deadline. The purpose of the NanoInfo 2015 workshop is to bring together stakeholders in order to assess the state of informatics relevant to the all aspects of the nanotechnology enterprise and to set priority targets for the future. From materials to processes to products; accessible data, information, models, and simulations will enable innovators to optimize performance and accelerate the innovation cycle from concept to product. Scientists and engineers will be able to efficiently assess the safety of new nanomaterials and quantitatively implement best practices of safe manufacturing and usage of nanomaterials throughout product lifecycles. Scientists will share predictive models and data that enable the design and discovery of nanomaterials and the resulting performance of systems that use them.Workshop Structure and Highlights NanoInfo 2015 will begin with a pre-workshop half-day tutorial, held on Monday, January 26 in the afternoon. The technical sessions will be held from Tuesday January 27 through Wednesday January 28. Accepted abstracts will be assigned to either a formal presentation session or to the poster presentation and discussion session on Tuesday.Workshop Exhibit and Sponsorship OpportunitiesNanoInfo 2015 is accepting sponsorship applications (http://nanoinformatics.org/node/54), offering marketing and workshop participation for those interested in supporting the event. Workshop Call for AbstractsThe NanoInfo 2015 online submission system is now open. Authors wishing to submit an abstract for review may do so by clicking on the 2015 Call for Presentations and Posters link (http://nanoinformatics.org/nidocuments/add). All submissions must be submitted using this online interface, and the deadline for Abstract submissions is December 15, 2014. Important Dates Abstract Submission Deadline December 15, 2014 Notification to Presenters December 17, 2014 Hotel Reservation Deadline December 29, 2014 Registration December - January 16, 2015 NanoInfo 2015 January 26-28, 2015

Extended Deadline - Call for Abstracts: Nanoinformatics Workshop 2015

National Nanomanufacturing Network - December 2, 2014 - 4:28am
Nanoinformatics Workshop: Enabling successful discovery and applications January 26-28, 2015Holiday Inn National Airport Hotel Arlington, VA NEW EXTENDED ABSTRACT SUBMISSION DEADLINE: January 4, 2015 The purpose of the Nanoinformatics 2015 workshop (http://nanoinformatics.org/2015/overview) is to bring together stakeholders in order to assess the state of informatics relevant to the all aspects of the nanotechnology enterprise and to set priority targets for the future. From materials to processes to products; accessible data, information, models, and simulations will enable innovators to optimize performance and accelerate the innovation cycle from concept to product. Scientists and engineers will be able to efficiently assess the safety of new nanomaterials and quantitatively implement best practices of safe manufacturing and usage of nanomaterials throughout product lifecycles. Scientists will share predictive models and data that enable the design and discovery of nanomaterials and the resulting performance of systems that use them.Workshop Structure and Highlights NanoInfo 2015 will begin with a pre-workshop half-day tutorial, held on Monday, January 26 in the afternoon. The technical sessions will be held from Tuesday January 27 through Wednesday January 28. Accepted abstracts will be assigned to either a formal presentation session or to the poster presentation and discussion session on Tuesday.The NanoInfo 2015 on-line submission system is now open Authors wishing to submit an abstract for review may do so by clicking here, on the 2015 Call for Presentations and Posters link (http://nanoinformatics.org/nidocuments/add ).Please note that all submissions must be submitted using this on-line interface. No other form of submission can be accepted.Please note, that while we have extended the abstract submission deadline, the hotel block reservations are only available before the December 29, 2014 hotel deadline. Important Dates Extended Abstract Submission Deadline January 4, 2015Notification to Presenters On a rolling basis Hotel Reservation Deadline December 29, 2014Registration December - January 16, 2015NanoInfo 2015January 26-28, 2015

NanoHybrids Launches its First Product Line of Premium Gold Nanoparticles

National Nanomanufacturing Network - December 2, 2014 - 4:23am
AUSTIN, TX NanoHybrids Corporation, a provider of nanotechnology-based contrast agents announced the launch of its new website and premium product line of gold nanoparticles specially designed to improve imaging results. The company’s initial technology platform was developed in collaboration with researchers from the Biomedical Engineering Department at The University of Texas at Austin and M.D. Anderson Cancer Center. "Frustrated by inconsistent imaging results due to highly variable shape, size and other properties of commercially available gold nanoparticle contrast agents, our team has developed highly monodisperse gold nanorods and nanospheres that will help scientists obtain consistent and better quality data. We also have a policy of ‘no proprietary coatings’ which means that unlike some companies in this space, we offer full transparency on surface chemistry, making it easier for our customers to modify and use these particles depending on their application," says Co-founder and Chief Technology Officer Dr. Kimberly Homan. NanoHybrids’ offerings include an exclusive line of silica-coated gold nanorods that are quickly gaining popularity as contrast agents in photoacoustic (optoacoustic) imaging. As opposed to current preclinical imaging contrast agents on the market, NanoHybrids’ silica-coated nanorods resist melting and shape distortion even when subjected to extreme heat via focused laser beams. In addition to providing this enhanced thermodynamic stability, the silica-coating also facilitates better heat transfer to the surrounding fluid, thus dramatically increasing signal strength. Overall, these benefits make the company’s silica-coated gold nanorods an excellent contrast agent for not only in vitro and in vivo photoacoustic imaging but also many other applications involving continuous or pulsed lasers. The founders at NanoHybrids have decades of experience in biomedical imaging and have been pioneering the development of contrast agents alongside custom designed imaging systems. "Our products have been developed by imaging researchers, for researchers. As scientists ourselves, we understand the challenges involved when working with gold nanoparticles in imaging and strive to provide the highest possible level of quality and technical support," says Homan. (http://www.nanohybrids.net)About NanoHybrids Inc. NanoHybrids is an Austin-based company focused on commercializing nanotechnology solutions. The company’s current product line comprises of premium gold nanoparticles with specialized coatings, including a proprietary silica coating that provides colloidal stability, bioconjugation potential and enhanced optical properties. NanoHybrids’ gold nanoparticles are ideal for use in imaging, tumor targeting, microscopy, lateral flow assays, SERS, drug delivery research, sensors and several other high-technology applications within the fields of life science and materials science. http://www.nanohybrids.net (http://www.nanohybrids.net) Product Applications: http://nanohybrids.net/pages/applications (http://nanohybrids.net/pages/applications) Products: http://nanohybrids.net/collections/all-products (http://nanohybrids.net/collections/all-products) Contact information: info at nanohybrids.net (mailto:info@nanohybrids.net)

Director Named for National Nanotechnology Coordination Office

National Nanomanufacturing Network - November 20, 2014 - 9:44am
The National Nanotechnology Coordination Office (NNCO) is pleased to announce the appointment of Dr. Michael A. Meador as its new Director. Dr. Meador joins NNCO on a detail from NASA, where he has been managing the Nanotechnology Project in the Game Changing Technology Program, a project involving five NASA centers, industry, and universities working to mature nanotechnologies with high potential for impact on NASA missions and to demonstrate them in selected applications.“Dr. Meador’s background and experience identifying nanotechnology applications, combined with his long involvement with the National Nanotechnology Initiative (NNI), will help us accelerate the NNI’s activities aimed at facilitating the commercialization of nanotechnology research sponsored by the Federal Government over the past decade,” said Dr. Lloyd Whitman, who has been serving as Interim NNCO Director and is now the Assistant Director for Nanotechnology at the Office of Science and Technology Policy. Dr. Meador, chair of NASA’s Nanotechnology Roadmap Team, was instrumental in developing the NASA-wide Nanotechnology Project, and has been responsible for project planning and advocacy, overseeing technical progress, developing external partnerships to advance and transfer technology, coordinating with other nanotechnology related activities within NASA, and interacting with program and senior agency management. He has also played a key role in representing NASA in the NNI’s interagency activities, including co-chairing its Nanomanufacturing, Industry Liaison, and Innovation Working Group. During his long career at NASA, Dr. Meador has held a series of positions with increasing responsibility, including over twenty years as Chief of the Polymers Branch of the Materials Division at NASA Glenn Research Center, where he expanded the research portfolio of the branch from research in high-temperature stable polymers and composites for aircraft engines to include work in battery electrolytes, fuel cell membranes, and nonlinear optical and sensor materials. He also initiated the first nanotechnology program at NASA Glenn. Dr. Meador has been recognized as the NASA Glenn Small Disadvantaged Business Program Technical Advocate of the Year and NASA Small Business Program Technical Personnel of the Year. He has also received the NASA Equal Opportunity Employment Medal for his work to increase the involvement of faculty and students from minority serving institutions in NASA materials research, and last month was awarded the NASA Exceptional Service Medal for leading NASA's Nanotechnology R D activities and representing the agency as a proactive member of the NNI.Source: NNCO (http://www.nano.gov/node/1246) The National Nanotechnology Coordination Office (NNCO) is pleased to announce the appointment of Dr. Michael A. Meador as its new Director. Dr. Meador joins NNCO on a detail from NASA, where he has been managing the Nanotechnology Project in the Game Changing Technology Program, a project involving five NASA centers, industry, and universities working to mature nanotechnologies with high potential for impact on NASA missions and to demonstrate them in selected applications. - See more at: http://www.nano.gov/node/1246#sthash.LAEDWssg.dpufThe National Nanotechnology Coordination Office (NNCO) is pleased to announce the appointment of Dr. Michael A. Meador as its new Director. Dr. Meador joins NNCO on a detail from NASA, where he has been managing the Nanotechnology Project in the Game Changing Technology Program, a project involving five NASA centers, industry, and universities working to mature nanotechnologies with high potential for impact on NASA missions and to demonstrate them in selected applications. “Dr. Meador’s background and experience identifying nanotechnology applications, combined with his long involvement with the National Nanotechnology Initiative (NNI), will help us accelerate the NNI’s activities aimed at facilitating the commercialization of nanotechnology research sponsored by the Federal Government over the past decade,” said Dr. Lloyd Whitman, who has been serving as Interim NNCO Director and is now the Assistant Director for Nanotechnology at the Office of Science and Technology Policy. Dr. Meador, chair of NASA’s Nanotechnology Roadmap Team, was instrumental in developing the NASA-wide Nanotechnology Project, and has been responsible for project planning and advocacy, overseeing technical progress, developing external partnerships to advance and transfer technology, coordinating with other nanotechnology related activities within NASA, and interacting with program and senior agency management. He has also played a key role in representing NASA in the NNI’s interagency activities, including co-chairing its Nanomanufacturing, Industry Liaison, and Innovation Working Group. During his long career at NASA, Dr. Meador has held a series of positions with increasing responsibility, including over twenty years as Chief of the Polymers Branch of the Materials Division at NASA Glenn Research Center, where he expanded the research portfolio of the branch from research in high-temperature stable polymers and composites for aircraft engines to include work in battery electrolytes, fuel cell membranes, and nonlinear optical and sensor materials. He also initiated the first nanotechnology program at NASA Glenn. Dr. Meador has been recognized as the NASA Glenn Small Disadvantaged Business Program Technical Advocate of the Year and NASA Small Business Program Technical Personnel of the Year. He has also received the NASA Equal Opportunity Employment Medal for his work to increase the involvement of faculty and students from minority serving institutions in NASA materials research, and last month was awarded the NASA Exceptional Service Medal for leading NASA's Nanotechnology R D activities and representing the agency as a proactive member of the NNI. - See more at: http://www.nano.gov/node/1246#sthash.QpleixbX.dpufhe National Nanotechnology Coordination Office (NNCO) is pleased to announce the appointment of Dr. Michael A. Meador as its new Director. Dr. Meador joins NNCO on a detail from NASA, where he has been managing the Nanotechnology Project in the Game Changing Technology Program, a project involving five NASA centers, industry, and universities working to mature nanotechnologies with high potential for impact on NASA missions and to demonstrate them in selected applications. “Dr. Meador’s background and experience identifying nanotechnology applications, combined with his long involvement with the National Nanotechnology Initiative (NNI), will help us accelerate the NNI’s activities aimed at facilitating the commercialization of nanotechnology research sponsored by the Federal Government over the past decade,” said Dr. Lloyd Whitman, who has been serving as Interim NNCO Director and is now the Assistant Director for Nanotechnology at the Office of Science and Technology Policy. Dr. Meador, chair of NASA’s Nanotechnology Roadmap Team, was instrumental in developing the NASA-wide Nanotechnology Project, and has been responsible for project planning and advocacy, overseeing technical progress, developing external partnerships to advance and transfer technology, coordinating with other nanotechnology related activities within NASA, and interacting with program and senior agency management. He has also played a key role in representing NASA in the NNI’s interagency activities, including co-chairing its Nanomanufacturing, Industry Liaison, and Innovation Working Group. During his long career at NASA, Dr. Meador has held a series of positions with increasing responsibility, including over twenty years as Chief of the Polymers Branch of the Materials Division at NASA Glenn Research Center, where he expanded the research portfolio of the branch from research in high-temperature stable polymers and composites for aircraft engines to include work in battery electrolytes, fuel cell membranes, and nonlinear optical and sensor materials. He also initiated the first nanotechnology program at NASA Glenn. Dr. Meador has been recognized as the NASA Glenn Small Disadvantaged Business Program Technical Advocate of the Year and NASA Small Business Program Technical Personnel of the Year. He has also received the NASA Equal Opportunity Employment Medal for his work to increase the involvement of faculty and students from minority serving institutions in NASA materials research, and last month was awarded the NASA Exceptional Service Medal for leading NASA's Nanotechnology R D activities and representing the agency as a proactive member of the NNI. - See more at: http://www.nano.gov/node/1246#sthash.QpleixbX.dpufhe National Nanotechnology Coordination Office (NNCO) is pleased to announce the appointment of Dr. Michael A. Meador as its new Director. Dr. Meador joins NNCO on a detail from NASA, where he has been managing the Nanotechnology Project in the Game Changing Technology Program, a project involving five NASA centers, industry, and universities working to mature nanotechnologies with high potential for impact on NASA missions and to demonstrate them in selected applications. “Dr. Meador’s background and experience identifying nanotechnology applications, combined with his long involvement with the National Nanotechnology Initiative (NNI), will help us accelerate the NNI’s activities aimed at facilitating the commercialization of nanotechnology research sponsored by the Federal Government over the past decade,” said Dr. Lloyd Whitman, who has been serving as Interim NNCO Director and is now the Assistant Director for Nanotechnology at the Office of Science and Technology Policy. Dr. Meador, chair of NASA’s Nanotechnology Roadmap Team, was instrumental in developing the NASA-wide Nanotechnology Project, and has been responsible for project planning and advocacy, overseeing technical progress, developing external partnerships to advance and transfer technology, coordinating with other nanotechnology related activities within NASA, and interacting with program and senior agency management. He has also played a key role in representing NASA in the NNI’s interagency activities, including co-chairing its Nanomanufacturing, Industry Liaison, and Innovation Working Group. During his long career at NASA, Dr. Meador has held a series of positions with increasing responsibility, including over twenty years as Chief of the Polymers Branch of the Materials Division at NASA Glenn Research Center, where he expanded the research portfolio of the branch from research in high-temperature stable polymers and composites for aircraft engines to include work in battery electrolytes, fuel cell membranes, and nonlinear optical and sensor materials. He also initiated the first nanotechnology program at NASA Glenn. Dr. Meador has been recognized as the NASA Glenn Small Disadvantaged Business Program Technical Advocate of the Year and NASA Small Business Program Technical Personnel of the Year. He has also received the NASA Equal Opportunity Employment Medal for his work to increase the involvement of faculty and students from minority serving institutions in NASA materials research, and last month was awarded the NASA Exceptional Service Medal for leading NASA's Nanotechnology R D activities and representing the agency as a proactive member of the NNI. - See more at: http://www.nano.gov/node/1246#sthash.QpleixbX.dpufhe National Nanotechnology Coordination Office (NNCO) is pleased to announce the appointment of Dr. Michael A. Meador as its new Director. Dr. Meador joins NNCO on a detail from NASA, where he has been managing the Nanotechnology Project in the Game Changing Technology Program, a project involving five NASA centers, industry, and universities working to mature nanotechnologies with high potential for impact on NASA missions and to demonstrate them in selected applications. “Dr. Meador’s background and experience identifying nanotechnology applications, combined with his long involvement with the National Nanotechnology Initiative (NNI), will help us accelerate the NNI’s activities aimed at facilitating the commercialization of nanotechnology research sponsored by the Federal Government over the past decade,” said Dr. Lloyd Whitman, who has been serving as Interim NNCO Director and is now the Assistant Director for Nanotechnology at the Office of Science and Technology Policy. Dr. Meador, chair of NASA’s Nanotechnology Roadmap Team, was instrumental in developing the NASA-wide Nanotechnology Project, and has been responsible for project planning and advocacy, overseeing technical progress, developing external partnerships to advance and transfer technology, coordinating with other nanotechnology related activities within NASA, and interacting with program and senior agency management. He has also played a key role in representing NASA in the NNI’s interagency activities, including co-chairing its Nanomanufacturing, Industry Liaison, and Innovation Working Group. During his long career at NASA, Dr. Meador has held a series of positions with increasing responsibility, including over twenty years as Chief of the Polymers Branch of the Materials Division at NASA Glenn Research Center, where he expanded the research portfolio of the branch from research in high-temperature stable polymers and composites for aircraft engines to include work in battery electrolytes, fuel cell membranes, and nonlinear optical and sensor materials. He also initiated the first nanotechnology program at NASA Glenn. Dr. Meador has been recognized as the NASA Glenn Small Disadvantaged Business Program Technical Advocate of the Year and NASA Small Business Program Technical Personnel of the Year. He has also received the NASA Equal Opportunity Employment Medal for his work to increase the involvement of faculty and students from minority serving institutions in NASA materials research, and last month was awarded the NASA Exceptional Service Medal for leading NASA's Nanotechnology R D activities and representing the agency as a proactive member of the NNI. - See more at: http://www.nano.gov/node/1246#sthash.QpleixbX.dpuf

Nanoimprint lithography for the fabrication of efficient low band gap polymer solar cells

National Nanomanufacturing Network - November 13, 2014 - 7:55am
In recent years, polymer solar cells have drawn considerable research interest due to their attractive features including flexibility, semi-transparency, and manufacturability using cost-effective continuous printing processes (read more: "The state of nanoimprinted polymer organic solar cell technology (http://www.nanowerk.com/spotlight/spotid=28622.php)"). However, one challenge limiting their commercialization is the relatively low power conversion efficiency when compared to inorganic solar cells."One of the causes for polymer solar cells' low performance is the difficulty to simultaneously realize donor-acceptor phase separation within the short exciton diffusion length (∼10 nm) and high charge mobility, especially hole mobility, which are critical for charge separation and transport," Yi Yang, a senior engineer at Globalfoundries, tells Nanowerk. "So far it has been impossible to achieve such a morphology in the most widely used bulk heterojunction structure in which randomly distributed phases cause significant charge recombination." New work, led by Walter Hu (http://www.ee.utdallas.edu/people/facultypages/Hu.html), an Associate Professor of Electrical Engineering, and Anvar Zakhidov (http://nanotech.utdallas.edu/personnel/staff/zakhidov.html), a professor of physics, both at UT Dallas, shows that nanoimprint lithography (NIL) is an effective technique to solve these issues simultaneously. The results, recently published in ACS Applied Materials Interfaces ("Efficient Low Bandgap Polymer Solar Cell with Ordered Heterojunction Defined by Nanoimprint Lithography" (http://dx.doi.org/doi:10.1021/am505303a)), show that low bandgap polymer solar cells with high efficiency of 5.5% can be fabricated using NIL. "Taking into account the fact that low bandgap polymers are becoming the main stream for this type of solar cell, we believe this technique will increasingly find more applications," says Yang. In a previous study ("How nanostructure geometry affects polymer photovoltaic device efficiency (http://www.nanowerk.com/spotlight/spotid=36631.php)"), the researchers focused on nanoimprinted P3HT solar cells. After carefully optimizing the nanostructure geometry, they achieved an efficiency of 3-4%, which is not as high as the efficiency record (over 4%) other groups have achieved with this polymer. In the new study, they extended their technique to low bandgap polymer solar cells and realized a high efficiency up to 5.5%, which is among the best efficiencies for this polymer reported in the literature. This result indicates that nanoimprint fabrication works better for low bandgap polymer solar cells. In the new work, the team demonstrates the feasibility of using nanoimprint lithography to make efficient low bandgap polymer solar cells with well-ordered heterojunction. They fabricate high-quality low bandgap conjugated polymer (PCPDTBT) nanogratings using this technique for the first time. "We found that NIL makes PCPDTBT chains interact more strongly and form an improved structural ordering," says Yang. "Solar cells made with the highest aspect ratio PCPDTBT nanostructures show a high power conversion efficiency of 5.5%. They are the most efficient nanoimprinted polymer solar cells, as well as the best reported solar cells using the same material." Nanoimprint lithography has emerged as an effective fabrication technique to precisely define the nanomorphology in polymer solar cells. Controlled chain ordering as well as a bicontinuous and interdigitized heterojunction can be achieved by imprinting conjugated polymers, where a nanoimprint induced chain alignment is present, followed by infiltrating fullerene into patterned polymer nanostructures. However, as Yang notes, most studies so far have focused on nanoimprinted P3HT/fullerene solar cells. "This material combination is not ideal due to a mismatch between the absorption of P3HT and solar spectrum, which has a maximum photon flux at 1.6-1.8 eV while P3HT has a relatively large bandgap of 1.9-2.0 eV," he explains. "A bandgap of 1.3-1.5 eV is considered to be ideal for polymer-fullerene solar cells." In recent years, many low bandgap polymers have been synthesized with record-breaking efficiencies. However, as Yang points out, it has been proven that the donor and acceptor phase separation for these polymers cannot be realized by thermal or solvent vapor annealing, which is usually carried out on P3HT/fullerene solar cells. Although additives such as 1,8-octanedithiol are added into the solution to help separate donor and acceptor domains, this separation cannot be controlled precisely. Therefore, NIL would provide an effective solution if an ordered active layer morphology could be formed by it. However, so far no results have been published that show that NIL can be applied to a wide variety of materials in the polymer solar cell field. Now, the UT Dallas team has utilized NIL to pattern the low bandgap (1.4 eV) solar cell polymer PCPDTBT. For the first time, they have used NIL to fabricate high quality nanogratings for this polymer. "After carefully optimizing the nanograting geometry, we were able to achieve a high solar cell efficiency of 5.5%," notes Yang. Furthermore, this work demonstrates that NIL is not only limited to solar cells made of the most widely studied polymer P3HT, but also can be applied to a wide variety of materials used in the fabrication of polymer solar cells – low bandgap polymers can also be patterned by this technique to make efficient devices. Despite considerable effort, the highest reported power conversion efficiencies obtained from nanoimprinted P3HT solar cells have been in the 3-4% range. These values are lower than the highest values (∼4-5%) when the same polymer is used in a bulk heterojunction structure. "This indicates that NIL works better for low bandgap polymer solar cells," says Yang. "One possible explanation is that the method of using thermal or solvent vapor annealing to control the phase separation in P3HT based bulk heterojunction solar cells is very effective, as shown by a number of studies; while that of using additives in the low bandgap polymer solar cells is not, as described in literature." "This less effective approach leaves NIL more space to demonstrate its advantage in improving the solar cell performance when compared to the bulk heterojunction structure," he concludes. "This is our preliminary thinking and more studies are required to understand these different behaviors. Also as predicted in our recent study, a larger interface area between polymer and fullerene is preferable for efficient devices. A practical way to further increase it is needed as well. Our future work will focus on these aspects." Source: Nanowerk (http://www.nanowerk.com/spotlight/spotid=38076.php)

Call for Presentations for Int'l Conf. on Nanotechnology for Renewable Materials

National Nanomanufacturing Network - November 13, 2014 - 4:30am
(http://www.tappi.org/15Nano) What’s New for 2015 Two Tracks for Presentations: As the Nano Conference continues to grow, this year there will be two tracks to guide attendees in choosing sessions to attend. The Fundamental Research Track will focus on new technical advances in characterization, isolation, functionalities and other properties of renewable and sustainable nanomaterials. The Industry Applications Track will focus on manufacturing applications, new markets, and other end user issues. The conference organizers have extended the Call for Submissions (https://www.eiseverywhere.com/file_uploads/7a30b75854987d218fd0996b1a0895f6_Nano2015CallForPresentations-Extension.pdf) .Abstracts are due by 1 December 2014. New Technology and Product Showcase: Promote your new products or technologies at this special session. Sponsors and exhibitors will be given priority for available slots. See the Call for Submissions tab for more details. Research Perspectives and Business Acumen Seminar: Designed for academics, this workshop will show how researchers can gain industrial support for their projects. Led by corporate R D directors, this workshop will have limited seating. Check the website for additional details. Plan to AttendExplore a world of possibilities for opening the door to new markets by unlocking the potential of renewable biomaterials. TAPPI’s tenth International Conference on Nanotechnology for Renewable Materials is the only event that explores how nanotechnology can transform biomaterials into high-value products that expand and transcend traditional forest products portfolios. Bringing together leading researchers, industry experts, government representatives and other stakeholders from around the world, this year’s event promises a unique, multi-disciplinary look at the rewards of using nanotechnology – from the forest to marketed products. Whether your focus is new product development, academic study or supplier research, this year’s conference will provide the big picture for unlocking value from this tiny technology. Conference Co-Chairs:Sean Ireland, Verso Paper (USA)Yaman Boluk, University of Alberta (Canada)Alain Dufresne, Grenoble Institute of Technology (France)Celebrating 100 Years of TAPPI!To honor TAPPI's 100th anniversary in 2015, the 2015 Conference will be held in Atlanta, Georgia, USA. TAPPI headquarters are located in Peachtree Corners, a northern suburb of Atlanta.