Featured Research

from universities, journals, and other organizations

Graphene sees the light: Sheets of carbon just one atom thick could be used in photovoltaic cells

Date:
December 19, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Sheets of carbon just one atom thick could make effective transparent electrodes in certain types of photovoltaic cells.

Sheets of carbon just one atom thick could make effective transparent electrodes in certain types of photovoltaic cells.

Graphene, a one-atom-thick sheet of carbon that is extremely strong and conducts electricity well, is the thinnest material ever made. Researchers believe that it could be used as a transparent electrode in photovoltaic cells, replacing a layer of indium tin oxide (ITO) that is brittle and becoming increasingly expensive.

Wee Shing Koh of the A*STAR Institute of High Performance Computing in Singapore and co-workers have compared these two materials. They found that graphene outperforms ITO when used with solar cells that absorb a broad spectrum of light

The wavelengths of light from the Sun have a range of intensities and deliver varying amounts of power. To maximize a photovoltaic device's performance, its transparent electrode should have a low electrical resistance, while also transmitting light of the right wavelengths for the cells to absorb.

Square sheets of graphene produced by today's chemical vapor deposition technology have an electrical resistance roughly four times that of a typical 100-nanometer-thick layer of ITO. Although adding more layers of graphene reduces its resistance, it also blocks more light. Koh and his co-workers calculated that four layers of graphene stacked together had the best chance of matching ITO's performance.

Graphene has one key advantage over ITO: it allows more than 97% of light to pass through to the solar cell beneath, regardless of its wavelength. In contrast, ITO tends to block certain wavelengths more than others. Four-layer graphene is slightly more transparent at near-infrared wavelengths than ITO is, for example.

Koh and co-workers estimated how each material would affect a flexible organic solar cell that absorbs light with wavelengths of 350 to 650 nanometers. They found that four layers of graphene delivered only 92.3% of the power of an equivalent ITO electrode. When paired with another organic photovoltaic device that operates from 350 to 750 nanometers, thus making it more effective at absorbing near-infrared light, graphene almost matched ITO's capabilities.

The researchers concluded that graphene would be ideally suited to photovoltaic cells with a very broad absorption range, such as a recently developed organic solar cell that can harvest light from 350 to 850 nanometers.

"With the refinement in the graphene manufacturing process, it would be possible for the sheet resistance of graphene to be an order of magnitude lower than the current state of the art," says Koh. This would allow just one or two sheets of graphene to beat ITO on both conductivity and transparency, making graphene transparent electrodes much more widely applicable.

The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Wee Shing Koh, Choon How Gan, Wee Kee Phua, Yuriy A. Akimov, Ping Bai. The Potential of Graphene as an ITO Replacement in Organic Solar Cells: An Optical Perspective. IEEE Journal of Selected Topics in Quantum Electronics, 2014; 20 (1): 4000107 DOI: 10.1109/JSTQE.2013.2247976

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Graphene sees the light: Sheets of carbon just one atom thick could be used in photovoltaic cells." ScienceDaily. ScienceDaily, 19 December 2013. <www.sciencedaily.com/releases/2013/12/131219154407.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, December 19). Graphene sees the light: Sheets of carbon just one atom thick could be used in photovoltaic cells. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2013/12/131219154407.htm
The Agency for Science, Technology and Research (A*STAR). "Graphene sees the light: Sheets of carbon just one atom thick could be used in photovoltaic cells." ScienceDaily. www.sciencedaily.com/releases/2013/12/131219154407.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Portable Breathalyzer Gets You Home Safely

Portable Breathalyzer Gets You Home Safely

Buzz60 (Oct. 21, 2014) Breeze, a portable breathalyzer, gets you home safely by instantly showing your blood alcohol content, and with one tap, lets you call an Uber, a cab or a friend from your contact list to pick you up. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
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


Space & Time

Matter & Energy

Computers & Math

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