Featured Research

from universities, journals, and other organizations

Simple, cheap way to increase solar cell efficiency

Date:
January 3, 2014
Source:
North Carolina State University
Summary:
Researchers have found an easy way to modify the molecular structure of a polymer commonly used in solar cells. Their modification can increase solar cell efficiency by more than 30 percent.

Side chain modification improves solar cell efficiency from 5.6% to 7.5%.
Credit: Image courtesy of North Carolina State University

Researchers from North Carolina State University and the Chinese Academy of Sciences have found an easy way to modify the molecular structure of a polymer commonly used in solar cells. Their modification can increase solar cell efficiency by more than 30 percent.

Related Articles


Polymer-based solar cells have two domains, consisting of an electron acceptor and an electron donor material. Excitons are the energy particles created by solar cells when light is absorbed. In order to be harnessed effectively as an energy source, excitons must be able to travel quickly to the interface of the donor and acceptor domains and retain as much of the light's energy as possible.

One way to increase solar cell efficiency is to adjust the difference between the highest occupied molecular orbit (HOMO) of the acceptor and lowest unoccupied molecular orbit (LUMO) levels of the polymer so that the exciton can be harvested with minimal loss. One of the most common ways to accomplish this is by adding a fluorine atom to the polymer's molecular backbone, a difficult, multi-step process that can increase the solar cell's performance, but has considerable material fabrication costs.

A team of chemists led by Jianhui Hou from the Chinese Academy of Sciences created a polymer known as PBT-OP from two commercially available monomers and one easily synthesized monomer. Wei Ma, a post-doctoral physics researcher from NC State and corresponding author on a paper describing the research, conducted the X-ray analysis of the polymer's structure and the donor:acceptor morphology.

PBT-OP was not only easier to make than other commonly used polymers, but a simple manipulation of its chemical structure gave it a lower HOMO level than had been seen in other polymers with the same molecular backbone. PBT-OP showed an open circuit voltage (the voltage available from a solar cell) value of 0.78 volts, a 36 percent increase over the ~ 0.6 volt average from similar polymers.

According to NC State physicist and co-author Harald Ade, the team's approach has several advantages. "The possible drawback in changing the molecular structure of these materials is that you may enhance one aspect of the solar cell but inadvertently create unintended consequences in devices that defeat the initial intent," he says. "In this case, we have found a chemically easy way to change the electronic structure and enhance device efficiency by capturing a lager fraction of the light's energy, without changing the material's ability to absorb, create and transport energy."

The researchers' findings appear in Advanced Materials. The research was funded by the U.S. Department of Energy, Office of Science, Basic Energy Science and the Chinese Ministry of Science and Technology. Dr. Maojie Zhang synthesized the polymers; Xia Guo,Shaoqing Zhang and Lijun Huo from the Chinese Academy of Sciences also contributed to the work.


Story Source:

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


Journal Reference:

  1. Maojie Zhang, Xia Guo, Wei Ma, Shaoqing Zhang, Lijun Huo, Harald Ade, Jianhui Hou. An Easy and Effective Method to Modulate Molecular Energy Level of the Polymer Based on Benzodithiophene for the Application in Polymer Solar Cells. Advanced Materials, 2013; DOI: 10.1002/adma.201304631

Cite This Page:

North Carolina State University. "Simple, cheap way to increase solar cell efficiency." ScienceDaily. ScienceDaily, 3 January 2014. <www.sciencedaily.com/releases/2014/01/140103204504.htm>.
North Carolina State University. (2014, January 3). Simple, cheap way to increase solar cell efficiency. ScienceDaily. Retrieved January 31, 2015 from www.sciencedaily.com/releases/2014/01/140103204504.htm
North Carolina State University. "Simple, cheap way to increase solar cell efficiency." ScienceDaily. www.sciencedaily.com/releases/2014/01/140103204504.htm (accessed January 31, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, January 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Rare Clouds Fill Grand Canyon

Raw: Rare Clouds Fill Grand Canyon

AP (Jan. 29, 2015) For the second time in two months, a rare weather phenomenon filled the Grand Canyon with thick clouds just below the rim on Wednesday. (Jan. 29) Video provided by AP
Powered by NewsLook.com
Senate Passes Bill for Keystone XL Pipeline

Senate Passes Bill for Keystone XL Pipeline

AP (Jan. 29, 2015) The Republican-controlled Senate has passed a bipartisan bill approving construction of the Keystone XL oil pipeline. (Jan. 29) Video provided by AP
Powered by NewsLook.com
"Cloud Inversion" In Grand Canyon

"Cloud Inversion" In Grand Canyon

Reuters - US Online Video (Jan. 29, 2015) Time lapse video captures a blanket of clouds amassing in the Grand Canyon -- the result of a rare meteorological process called "cloud inversion." Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Why Researchers Say We Should Cut Back On Biofuels

Why Researchers Say We Should Cut Back On Biofuels

Newsy (Jan. 29, 2015) Biofuels aren&apos;t the best alternative to fossil fuels, according to a new report. In fact, they&apos;re quite a bad one. 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