{"id":613,"date":"2014-10-14T04:37:27","date_gmt":"2014-10-14T04:37:27","guid":{"rendered":"http:\/\/revoscience.com\/en\/?p=613"},"modified":"2014-10-14T04:39:56","modified_gmt":"2014-10-14T04:39:56","slug":"how-to-make-a-perfect-solar-absorber","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/how-to-make-a-perfect-solar-absorber\/","title":{"rendered":"How to make a \u201cperfect\u201d solar absorber"},"content":{"rendered":"

New system aims to harness the full spectrum of available solar radiation.<\/strong><\/p>\n

\"Ideal-Solar-Absorber\"<\/a>
\n<\/strong>CAMBRIDGE, Mass–The key to creating a material that would be ideal for converting solar energy to heat is tuning the material\u2019s spectrum of absorption just right: It should absorb virtually all wavelengths of light that reach Earth\u2019s surface from the sun \u2014 but not much of the rest of the spectrum, since that would increase the energy that is reradiated by the material, and thus lost to the conversion process.
\n<\/strong><\/p>\n

Now researchers at MIT say they have accomplished the development of a material that comes very close to the \u201cideal\u201d for solar absorption. The material is a two-dimensional metallic dielectric photonic crystal, and has the additional benefits of absorbing sunlight from a wide range of angles and withstanding extremely high temperatures. Perhaps most importantly, the material can also be made cheaply at large scales.<\/p>\n

The creation of this material is described in a paper appearing this week in the journal\u00a0Advanced Materials<\/em>, co-authored by MIT postdoc Jeffrey Chou, professors Marin Soljacic, Nicholas Fang, Evelyn Wang, and Sang-Gook Kim, and five others.<\/p>\n

The material works as part of a solar-thermophotovoltaic (STPV) device: The sunlight\u2019s energy is first converted to heat, which then causes the material to glow, emitting light that can, in turn, be converted to an electric current.<\/p>\n

Some members of the team worked on an earlier STPV device that took the form of hollow cavities, explains Chou, of MIT\u2019s Department of Mechanical Engineering, who is the paper\u2019s lead author. \u201cThey were empty, there was air inside,\u201d he says. \u201cNo one had tried putting a dielectric material inside, so we tried that and saw some interesting properties.\u201d<\/p>\n

When harnessing solar energy, \u201cyou want to trap it and keep it there,\u201d Chou says; getting just the right spectrum of both absorption and emission is essential to efficient STPV performance.<\/p>\n

Most of the sun\u2019s energy reaches us within a specific band of wavelengths, Chou explains, ranging from the ultraviolet through visible light and into the near-infrared. \u201cIt\u2019s a very specific window that you want to absorb in,\u201d he says. \u201cWe built this structure, and found that it had a very good absorption spectrum, just what we wanted.\u201d<\/p>\n

In addition, the absorption characteristics can be controlled with great precision: The material is made from a collection of nanocavities, and \u201cyou can tune the absorption just by changing the size of the nanocavities,\u201d Chou says.<\/p>\n

Another key characteristic of the new material, Chou says, is that it is well matched to existing manufacturing technology. \u201cThis is the first-ever device of this kind that can be fabricated with a method based on current \u2026 techniques, which means it\u2019s able to be manufactured on silicon wafer scales,\u201d Chou says \u2014 up to 12 inches on a side. Earlier lab demonstrations of similar systems could only produce devices a few centimeters on a side with expensive metal substrates, so were not suitable for scaling up to commercial production, he says.<\/p>\n

In order to take maximum advantage of systems that concentrate sunlight using mirrors, the material must be capable of surviving unscathed under very high temperatures, Chou says. The new material has already demonstrated that it can endure a temperature of 1,000 degrees Celsius (1,832 degrees Fahrenheit) for a period of 24 hours without severe degradation.<\/p>\n

And since the new material can absorb sunlight efficiently from a wide range of angles, Chou says, \u201cwe don\u2019t really need solar trackers\u201d \u2014 which would add greatly to the complexity and expense of a solar power system.<\/p>\n

\u201cThis is the first device that is able to do all these things at the same time,\u201d Chou says. \u201cIt has all these ideal properties.\u201d<\/p>\n

While the team has demonstrated working devices using a formulation that includes a relatively expensive metal, ruthenium, \u201cwe\u2019re very flexible about materials,\u201d Chou says. \u201cIn theory, you could use any metal that can survive these high temperatures.\u201d<\/p>\n

The group is now working to optimize the system with alternative metals. Chou expects the system could be developed into a commercially viable product within five years. He is working with Kim on applications from this project.<\/p>\n

The team also included MIT research scientist Ivan Celanovic and former graduate students Yi Yeng, Yoonkyung Lee, Andrej Lenert, and Veronika Rinnerbauer. The work was supported by the Solid-State Solar Thermal Energy Conversion Center and the U.S. Department of Energy.<\/p>\n

Providedy by MIT , and writtend by \u00a0David Chandler, MIT News Office<\/em><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

New system aims to harness the full spectrum of available solar radiation. CAMBRIDGE, Mass–The key to creating a material that would be ideal for converting solar energy to heat is tuning the material\u2019s spectrum of absorption just right: It should absorb virtually all wavelengths of light that reach Earth\u2019s surface from the sun \u2014 but […]<\/p>\n","protected":false},"author":2,"featured_media":614,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14,17,28],"tags":[],"class_list":["post-613","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-innovation","category-research","category-techbiz"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber-150x150.jpg",150,150,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber-300x200.jpg",300,200,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",600,400,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",600,400,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",540,360,false],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",95,63,false],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",639,426,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",96,64,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2014\/10\/Ideal-Solar-Absorber.jpg",150,100,false]},"author_info":{"info":["RevoScience"]},"category_info":"Innovation<\/a> Research<\/a> Tech<\/a>","tag_info":"Tech","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/613","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=613"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/613\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/614"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=613"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}