Featured Research

from universities, journals, and other organizations

Specially designed nanostructured materials can increase the light-absorbing efficiency of solar cells

Date:
November 20, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
The Sun is our most promising source of clean and renewable energy. The energy that reaches Earth from the Sun in an hour is almost equivalent to that consumed by humans over a year. Solar cells can tap this massive source of energy by converting light into an electrical current. However, these devices still require significant improvements in efficiency before they can compete with more traditional energy sources. New research has increased the light-absorbing efficiency of solar cells.

Nanoparticles (green) convert near-infrared radiation (NIR) to visible light (VIS), which can be absorbed by quantum dots (red). This creates electrons (e-) which are injected into the titanium oxide (blue) scaffold.
Credit: Copyright : 2013 A*STAR Institute of Materials Research and Engineering

The Sun is our most promising source of clean and renewable energy. The energy that reaches Earth from the Sun in an hour is almost equivalent to that consumed by humans over a year. Solar cells can tap this massive source of energy by converting light into an electrical current. However, these devices still require significant improvements in efficiency before they can compete with more traditional energy sources.

Xiaogang Liu, Alfred Ling Yoong Tok and their co-workers at the A*STAR Institute of Materials Research and Engineering, the National University of Singapore and Nanyang Technological University, Singapore, have now developed a method for using nanostructures to increase the fraction of incoming light that is absorbed by a light-harvesting material1. The method is ideal for use with high-efficiency solar cells.

Solar cells absorb packets of optical energy called photons and then use the photons to generate electrons. The energy of some photons from the Sun, however, is too small to create electrons in this way and so is lost. Liu, Tok and their co-workers circumvented this loss using an effect known as upconversion. In this process, two low-energy photons are combined to produce a single high-energy photon. This energetic photon can then be absorbed by the active region of the solar cell.

The researchers' device comprised a titanium oxide frame filled with a regular arrangement of air pores roughly half a micrometer across -- a structure called an inverse opal (see image). Spheres of the upconversion material, which were 30 nanometers in diameter, sat on the surface of these pores. Tiny light-sensitive quantum dots made of crystals of cadmium selenide coated these nanospheres.

The quantum dots efficiently absorbed incoming light, either directly from an external source or from unconverted photons from the nanospheres, and converted it to electrons. This charge then flowed into the titanium oxide frame. "The titanium oxide inverse opal creates a continuous electron-conducting pathway and provides a large interfacial surface area to support the upconversion nanoparticles and the quantum dots," explains Liu.

Liu, Tok and the team tested the device by firing laser light at it with a wavelength of 980 nanometers, which is not normally absorbed by cadmium selenide quantum dots. As expected, they were able to measure a much higher electrical current than the same experiment performed with a device without the upconversion nanospheres. "We believe that the enhanced energy transfer and light harvesting may afford a highly competitive advantage over conventional silicon solar cells," says Liu.


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. Liap Tat Su, Siva Krishna Karuturi, Jingshan Luo, Lijun Liu, Xinfeng Liu, Jun Guo, Tze Chien Sum, Renren Deng, Hong Jin Fan, Xiaogang Liu, Alfred Iing Yoong Tok. Photon Upconversion in Hetero-nanostructured Photoanodes for Enhanced Near-Infrared Light Harvesting. Advanced Materials, 2013; 25 (11): 1603 DOI: 10.1002/adma.201204353

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Specially designed nanostructured materials can increase the light-absorbing efficiency of solar cells." ScienceDaily. ScienceDaily, 20 November 2013. <www.sciencedaily.com/releases/2013/11/131120103444.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, November 20). Specially designed nanostructured materials can increase the light-absorbing efficiency of solar cells. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2013/11/131120103444.htm
The Agency for Science, Technology and Research (A*STAR). "Specially designed nanostructured materials can increase the light-absorbing efficiency of solar cells." ScienceDaily. www.sciencedaily.com/releases/2013/11/131120103444.htm (accessed October 22, 2014).

Share This



More Earth & Climate News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) — The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) — Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

Newsy (Oct. 20, 2014) — The United Nations says water is a human right, but should it be free? Detroit has cut off water to residents who can't pay, and the U.N. isn't happy. 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