Featured Research

from universities, journals, and other organizations

Measurement of 'hot' electrons could have solar energy payoff; Nanoantennas hold promise for infrared photovoltaics

Date:
May 9, 2011
Source:
Rice University
Summary:
Basic scientific curiosity paid off in unexpected ways when researchers investigating the fundamental physics of nanomaterials discovered a new technology that could dramatically improve solar energy panels.

Basic scientific curiosity paid off in unexpected ways when Rice University researchers investigating the fundamental physics of nanomaterials discovered a new technology that could dramatically improve solar energy panels.

The research is described in a new paper in the journal Science.

"We're merging the optics of nanoscale antennas with the electronics of semiconductors," said lead researcher Naomi Halas, Rice's Stanley C. Moore Professor in Electrical and Computer Engineering. "There's no practical way to directly detect infrared light with silicon, but we've shown that it is possible if you marry the semiconductor to a nanoantenna. We expect this technique will be used in new scientific instruments for infrared-light detection and for higher-efficiency solar cells."

More than a third of the solar energy on Earth arrives in the form of infrared light. But silicon -- the material that's used to convert sunlight into electricity in the vast majority of today's solar panels -- cannot capture infrared light's energy. Every semiconductor, including silicon, has a "bandgap" where light below a certain frequency passes directly through the material and is unable to generate an electrical current. By attaching a metal nanoantenna to the silicon, where the tiny antenna is specially tuned to interact with infrared light, the Rice team showed they could extend the frequency range for electricity generation into the infrared. When infrared light hits the antenna, it creates a "plasmon," a wave of energy that sloshes through the antenna's ocean of free electrons. The study of plasmons is one of Halas' specialties, and the new paper resulted from basic research into the physics of plasmons that began in her lab years ago.

It has been known that plasmons decay and give up their energy in two ways; they either emit a photon of light or they convert the light energy into heat. The heating process begins when the plasmon transfers its energy to a single electron -- a 'hot' electron. Rice graduate student Mark Knight, lead author on the paper, together with Rice theoretical physicist Peter Nordlander, his graduate student Heidar Sobhani, and Halas set out to design an experiment to directly detect the hot electrons resulting from plasmon decay.

Patterning a metallic nanoantenna directly onto a semiconductor to create a "Schottky barrier," Knight showed that the infrared light striking the antenna would result in a hot electron that could jump the barrier, which creates an electrical current. This works for infrared light at frequencies that would otherwise pass directly through the device.

"The nanoantenna-diodes we created to detect plasmon-generated hot electrons are already pretty good at harvesting infrared light and turning it directly into electricity," Knight said. "We are eager to see whether this expansion of light-harvesting to infrared frequencies will directly result in higher-efficiency solar cells."


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Mark W. Knight, Heidar Sobhani, Peter Nordlander, and Naomi J. Halas. Photodetection with Active Optical Antennas. Science, 2011; 332 (6030): 702-704 DOI: 10.1126/science.1203056

Cite This Page:

Rice University. "Measurement of 'hot' electrons could have solar energy payoff; Nanoantennas hold promise for infrared photovoltaics." ScienceDaily. ScienceDaily, 9 May 2011. <www.sciencedaily.com/releases/2011/05/110505142604.htm>.
Rice University. (2011, May 9). Measurement of 'hot' electrons could have solar energy payoff; Nanoantennas hold promise for infrared photovoltaics. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2011/05/110505142604.htm
Rice University. "Measurement of 'hot' electrons could have solar energy payoff; Nanoantennas hold promise for infrared photovoltaics." ScienceDaily. www.sciencedaily.com/releases/2011/05/110505142604.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
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:
from the past week

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