Featured Research

from universities, journals, and other organizations

Los Alamos Researchers Working To Harness Photosynthesis

Date:
April 7, 1998
Source:
Los Alamos National Laboratory
Summary:
Researchers from the U.S. Department of Energy's Los Alamos National Laboratory are hoping to harvest the sun's energy the way plants do.

DALLAS -- Researchers from the U.S. Department of Energy's Los Alamos National Laboratory are hoping to harvest the sun's energy the way plants do.

At the American Chemical Society's recent annual meeting (March 29, 1998) in Dallas, Greg Van Patten, a researcher in Los Alamos' Bioscience and Biotechnology Group, outlined how he and his colleagues are developing methods to use thin films of dyes to capture light and convert it into energy.

"We're studying energy transfer processes that are analogous to photosynthesis," said Van Patten. "We ultimately hope to develop a more efficient means of grabbing solar energy and converting it into electrical power."

Van Patten and his colleagues are developing a simple, environmentally friendly method of depositing thin layers of dyes on a glass substrate to create a better solar collector. Each dye, able to absorb a certain wavelength of light, would be deposited on the substrate in sequence; although the plate would look dark to the human eye, a cross-section would reveal a rainbow of colored layers piled on top of one another.

By layering the dyes, Van Patten and his colleagues hope to capture as much available light as possible -- ultimately, more than can be collected with current semiconductor solar panels.

For example, a layer that appears green to the naked eye absorbs most of the spectrum except for the green wavelength, which is reflected back to the human eye to be seen. Other layers capture other portions of the spectrum and reflect back the portions that appear to the human eye as the layers' respective colors. To a human observer looking down on the plate, very little light would be reflected back, so the plate would appear dark, or black if it were absorbing all visible wavelengths.

Van Patten and his Los Alamos collaborators are using chemicals that will allow them to build up layers simply by dunking the substrate into a dye solution. This low-tech, low-cost method avoids the use of potentially hazardous organic chemicals common to some thin-film deposition techniques.

The simplicity comes from the chemicals themselves. In order to build up the layers, researchers coat the glass substrate with a polymer that has positively charged sites. Next, the substrate is dipped into a solution that contains negatively charged dye particles. The dye ions are attracted to the positively charged polymer layer and they stick to it. After the dye layer is applied, another layer of polymer is added and the collector is ready for dipping into another dye solution. The process can be repeated until all dye layers are applied.

Van Patten and his colleagues -- Victor Klimov, Duncan McBranch and Robert Donohoe of Los Alamos's Chemical Science and Technology Division -- are working to perfect the first dye layer. Van Patten and the Los Alamos group are using a dye that comes from a class of molecules called porphyrins.

"Porphyrins are the same class of dye as chlorophyll found in plants," said Van Patten.

The porphyrin molecule has four negatively charged branches radiating from a central cluster of chemical rings. Van Patten is experimenting with how different metal ion species added to the interior affect energy transfer. In this case, Van Patten and his colleagues are using porphyrins with zinc ions in the center.

When light hits the porphyrin, the molecule absorbs a photon and moves to an electronically excited state. Since molecules like to remain at the lowest stable energy level possible, the porphyrin will try to transfer its energy to a neighboring molecule of lower energy, which in turn will try to pass energy to its neighbor and so on - like a line of people passing a bucket of water from a well to a burning barn.

The idea behind Van Patten's light-harvesting multi-layer film is to get the molecules to pass their energy from one molecule to the next through all the different dye layers until the energy can be passed into a "trap."

A similar mechanism occurs in plants. When a plant porphyrin captures a photon, it passes its energy around to other porphyrins that are clustered around an energy center. Like a pinball bouncing off bumpers, the energy is transferred between porphyrins until it strikes the energy center. The plant then can "digest" and use the energy.

Zinc-space porphyrins transfer energy well while in solution, but they behave differently on the film. Van Patten believes that part of the problem is the way in which the molecules attach themselves to the substrate.

"We will experiment with the chemistry of the molecules to see if we can get them to line up on the substrate in an orderly fashion once the substrate is dipped into the dye solution," he said.

Van Patten and his colleagues are experimenting with other dyes to see how they behave on a substrate and how well they transfer energy.

If the Los Alamos research is successful, it may have applications beyond solar collectors. Energy-transferring films could be used in a number of applications, including devices that could use sunlight to transform toxic environmental contaminants into harmless substances.

Los Alamos National Laboratory is operated by the University of California for the U.S. Department of Energy.


Story Source:

The above story is based on materials provided by Los Alamos National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Los Alamos National Laboratory. "Los Alamos Researchers Working To Harness Photosynthesis." ScienceDaily. ScienceDaily, 7 April 1998. <www.sciencedaily.com/releases/1998/04/980407075903.htm>.
Los Alamos National Laboratory. (1998, April 7). Los Alamos Researchers Working To Harness Photosynthesis. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/1998/04/980407075903.htm
Los Alamos National Laboratory. "Los Alamos Researchers Working To Harness Photosynthesis." ScienceDaily. www.sciencedaily.com/releases/1998/04/980407075903.htm (accessed July 26, 2014).

Share This




More Matter & Energy News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
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

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