{"71429":{"#nid":"71429","#data":{"type":"news","title":"Fiber-based Nanotechnology Could Power Electronic Devices","body":[{"value":"\u003Cp\u003ENanotechnology researchers are developing the perfect complement to the power tie: a \u0022power shirt\u0022 able to generate electricity to power small electronic devices for soldiers in the field, hikers and others whose physical motion could be harnessed and converted to electrical energy.\u003C\/p\u003E\n\u003Cp\u003EThe February 14 issue of the journal \u003Cem\u003ENature\u003C\/em\u003E details how pairs of textile fibers covered with zinc oxide nanowires can generate electrical current using the piezoelectric effect.  Combining current flow from many fiber pairs woven into a shirt or jacket could allow the wearer\u0027s body movement to power a range of portable electronic devices.  The fibers could also be woven into curtains, tents or other structures to capture energy from wind motion, sound vibration or other mechanical energy.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The fiber-based nanogenerator would be a simple and economical way to harvest energy from physical movement,\u0022 said Zhong Lin Wang, a Regents professor in the School of Materials Science and Engineering at the Georgia Institute of Technology.  \u0022If we can combine many of these fibers in double or triple layers in clothing, we could provide a flexible, foldable and wearable power source that, for example, would allow people to generate their own electrical current while walking.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe research was sponsored by the National Science Foundation, the U.S. Department of Energy and the Emory-Georgia Tech Nanotechnology Center for Personalized and Predictive Oncology.\n\u003C\/p\u003E\n\u003Cp\u003EThe microfiber-nanowire hybrid system builds on the nanowire nanogenerator that Wang\u0027s research team announced in the journal \u003Cem\u003EScience\u003C\/em\u003E in April 2007.  That system generates current from arrays of vertically-aligned zinc oxide (ZnO) nanowires that flex beneath an electrode containing conductive platinum tips.  The nanowire nanogenerator was designed to harness energy from environmental sources such as ultrasonic waves, mechanical vibrations or blood flow.\n\u003C\/p\u003E\n\u003Cp\u003EThe nanogenerators developed by Wang\u0027s research group take advantage of the unique coupled piezoelectric and semiconducting properties of zinc oxide nanostructures, which produce small electrical charges when they are flexed.  After a year of development, the original nanogenerators - which are two by three millimeters square - can produce up to 800 nanoamperes and 20 millivolts.\n\u003C\/p\u003E\n\u003Cp\u003EThe microfiber generators rely on the same principles, but are made from soft materials and designed to capture energy from low-frequency mechanical energy.  They consist of DuPont Kevlar fibers on which zinc oxide nanowires have been grown radially and embedded in a polymer at their roots, creating what appear to be microscopic baby-bottle brushes with billions of bristles.  One of the fibers in each pair is also coated with gold to serve as the electrode and to deflect the nanowire tips.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The two fibers scrub together just like two bottle brushes with their bristles touching, and the piezoelectric-semiconductor process converts the mechanical motion into electrical energy,\u0022 Wang explained.  \u0022Many of these devices could be put together to produce higher power output.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EWang and collaborators Xudong Wang and Yong Qin have made more than 200 of the fiber nanogenerators.  Each is tested on an apparatus that uses a spring and wheel to move one fiber against the other.  The fibers are rubbed together for up to 30 minutes to test their durability and power production.\n\u003C\/p\u003E\n\u003Cp\u003ESo far, the researchers have measured current of about four nanoamperes and output voltage of about four millivolts from a nanogenerator that included two fibers that were each one centimeter long. With a much improved design, Wang estimates that a square meter of fabric made from the special fibers could theoretically generate as much as 80 milliwatts of power.\n\u003C\/p\u003E\n\u003Cp\u003EFabrication of the microfiber nanogenerator begins with coating a 100-nanometer seed layer of zinc oxide onto the Kevlar using magnetron sputtering.  The fibers are then immersed in a reactant solution for approximately 12 hours, which causes nanowires to grow from the seed layer at a temperature of 80 degrees Celsius.  The growth produces uniform coverage of the fibers, with typical lengths of about 3.5 microns and several hundred nanometers between each fiber.\n\u003C\/p\u003E\n\u003Cp\u003ETo help maintain the nanowires\u0027 connection to the Kevlar, the researchers apply two layers of tetraethoxysilane (TEOS) to the fiber.  \u0022First we coat the fiber with the polymer, then with a zinc oxide layer,\u0022 Wang explained.  \u0022Then we grow the nanowires and re-infiltrate the fiber with the polymer.  This helps to avoid scrubbing off the nanowires when the fibers rub together.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EFinally, the researchers apply a 300 nanometer layer of gold to some of the nanowire-covered Kevlar.  The two different fibers are then paired up and entangled to ensure that a gold-coated fiber contacts a fiber covered only with zinc oxide nanowires.  The gold fibers serve as a Shottky barrier with the zinc oxide, substituting for the platinum-tipped electrode used in the original nanogenerator.  \n\u003C\/p\u003E\n\u003Cp\u003ETo ensure that the current they measured was produced by the piezoelectric-semiconductor effect and not just static electricity, the researchers conducted several tests.  They tried rubbing gold fibers together, and zinc oxide fibers together, neither of which produced current.  They also reversed the polarity of the connections, which changed the output current and voltage.\n\u003C\/p\u003E\n\u003Cp\u003EBy allowing nanowire growth to take place at temperatures as low as 80 degrees Celsius, the new fabrication technique would allow the nanostructures to be grown on virtually any shape or substrate.  \n\u003C\/p\u003E\n\u003Cp\u003EAs a next step, the researchers want to combine multiple fiber pairs to increase the current and voltage levels.  They also plan to improve conductance of their fibers.\n\u003C\/p\u003E\n\u003Cp\u003EHowever, one significant challenge lies head for the power shirt - washing it.  Zinc oxide is sensitive to moisture, so in real shirts or jackets, the nanowires would have to be protected from the effects of the washing machine, Wang noted.\n\u003C\/p\u003E\n\u003Cp\u003EThe research is supported by the NSF\u0027s Division of Materials Research through grant 0706436.  \u0022This multi-disciplinary research grant enables materials scientists and engineers from varied backgrounds to work together toward translating basic and applied research into viable technologies,\u0022 noted Harsh Deep Chopra, NSF\u0027s program manager.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Vogel (404-385-3364); E-mail: (\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E)\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ETechnical Contact\u003C\/strong\u003E: Zhong Lin Wang (404-894-8008); E-mail: (\u003Ca href=\u0022mailto:zhong.wang@mse.gatech.edu\u0022\u003Ezhong.wang@mse.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"\u0022Power shirt\u0022 would harvest energy from physical movement"}],"field_summary":[{"value":"Nanotechnology researchers are developing the perfect complement to the power tie: a \u0022power shirt\u0022 able to generate electricity to power small electronic devices for soldiers in the field, hikers and others whose physical motion could be harnessed and converted to electrical energy.","format":"limited_html"}],"field_summary_sentence":[{"value":"Nanogenerators could power electronics from physical movement"}],"uid":"27303","created_gmt":"2008-02-13 01:00:00","changed_gmt":"2016-10-08 03:03:24","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2008-02-13T00:00:00-05:00","iso_date":"2008-02-13T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"71430":{"id":"71430","type":"image","title":"Z.L. Wang and microfiber nanogenerator","body":null,"created":"1449177376","gmt_created":"2015-12-03 21:16:16","changed":"1475894637","gmt_changed":"2016-10-08 02:43:57"},"71431":{"id":"71431","type":"image","title":"Microscope image","body":null,"created":"1449177376","gmt_created":"2015-12-03 21:16:16","changed":"1475894637","gmt_changed":"2016-10-08 02:43:57"},"71432":{"id":"71432","type":"image","title":"Fiber nanogenerator schematic","body":null,"created":"1449177376","gmt_created":"2015-12-03 21:16:16","changed":"1475894637","gmt_changed":"2016-10-08 02:43:57"}},"media_ids":["71430","71431","71432"],"related_links":[{"url":"http:\/\/www.mse.gatech.edu\/","title":"Georgia Tech School of Materials Science and Engineering"},{"url":"http:\/\/www.nanoscience.gatech.edu\/zlwang\/","title":"Team Web site"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"144","name":"Energy"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"},{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"2123","name":"current"},{"id":"436","name":"electricity"},{"id":"1493","name":"Fiber"},{"id":"1334","name":"nanogenerator"},{"id":"3517","name":"power"},{"id":"7487","name":"zinc-oxide"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}