Featured Research

from universities, journals, and other organizations

Harnessing the energy of the Sun: New technique improves artificial photosynthesis

Date:
May 11, 2011
Source:
Ecole Polytechnique Fédérale de Lausanne
Summary:
Transforming solar energy into a usable form is a real challenge. One technique is to use semiconductors to store the energy as hydrogen. Unfortunately, the most efficient semiconductors are not the most stable. Scientists have just discovered that it is possible to protect the semiconductor with a uniform layer just a few nanometers thick.

Transforming solar energy into a usable form is a real challenge. One technique is to use semiconductors to store the energy as hydrogen. Unfortunately, the most efficient semiconductors are not the most stable. An EPFL team has just discovered that it is possible to protect the semiconductor with a uniform layer just a few nanometers thick.

Related Articles


This discovery will make it possible to improve photoelectrochemical cells. In the same way that plants use photosynthesis to transform sunlight into energy, these cells use sunlight to drive chemical reactions that ultimately produce hydrogen from water. The process involves using a light-sensitive semi-conducting material such as cuprous oxide to provide the current needed to fuel the reaction. Although it is not expensive, the oxide is unstable if exposed to light in water. Research by

Adriana Paracchino and Elijah Thimsen, published May 8, 2011 in the journal Nature Materials, demonstrates that this problem can be overcome by covering the semiconductor with a thin film of atoms using the atomic layer deposition (ALD) technique.

Under the supervision of Professor Michael Grätzel in EPFL's Laboratory of Photonics and Interfaces, the two scientists achieved this remarkable feat by combining techniques used at the industrial scale, and then applying them to the problem of producing hydrogen. With their process, cuprous oxide can be simply and effectively protected from contact with water, making it possible to use it as a semiconductor. The advantages are numerous: cuprous oxide is abundantly available and inexpensive; the protective layer is completely impermeable, regardless of the roughness of the surface; and the process can easily be scaled up for industrial fabrication.

A promising technique

The research team developed the technique by "growing" layers of zinc oxide and titanium oxide, one atom-thick layer at a time, on the cuprous oxide surface. By using the ALD technique, they were able to control the thickness of the protective layer down to the precision of a single atom over the entire surface. This level of precision guarantees the stability of the semiconductor while preserving all of its hydrogen-producing efficiency. The next step in the research will be to improve the electrical properties of the protective layer.

Using widely available materials and techniques that can be easily scaled up will help the "green" photoelectrochemical production of hydrogen meet the needs of industry.


Story Source:

The above story is based on materials provided by Ecole Polytechnique Fédérale de Lausanne. Note: Materials may be edited for content and length.


Journal Reference:

  1. Adriana Paracchino, Vincent Laporte, Kevin Sivula, Michael Grätzel, Elijah Thimsen. Highly active oxide photocathode for photoelectrochemical water reduction. Nature Materials, 2011; DOI: 10.1038/NMAT3017

Cite This Page:

Ecole Polytechnique Fédérale de Lausanne. "Harnessing the energy of the Sun: New technique improves artificial photosynthesis." ScienceDaily. ScienceDaily, 11 May 2011. <www.sciencedaily.com/releases/2011/05/110510134110.htm>.
Ecole Polytechnique Fédérale de Lausanne. (2011, May 11). Harnessing the energy of the Sun: New technique improves artificial photosynthesis. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2011/05/110510134110.htm
Ecole Polytechnique Fédérale de Lausanne. "Harnessing the energy of the Sun: New technique improves artificial photosynthesis." ScienceDaily. www.sciencedaily.com/releases/2011/05/110510134110.htm (accessed October 26, 2014).

Share This



More Earth & Climate News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) — EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) — A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) — Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins