Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Think Pink to Produce "Green" Solar Energy

31.07.2007
When it comes to producing earth-friendly solar energy, pink may be the new green, according to Ohio State University researchers.

Scientists here have developed new dye-sensitized solar cells (DSSCs) that get their pink color from a mixture of red dye and white metal oxide powder in materials that capture light.

Currently, the best of these new pink materials convert light to electricity with only half the efficiency of commercially-available silicon-based solar cells -- but they do so at only one quarter of the cost, said Yiying Wu, assistant professor of chemistry at Ohio State.

And Wu is hoping for even better.

"We believe that one day, DSSC efficiency can reach levels comparable to any solar cell," he said. "The major advantage of DSSCs is that the cost is low. That is why DSSCs are so interesting to us, and so important."

Pink is a typical color for DSSCs. Most use dyes containing ruthenium, which has a red color; the metal oxide powder that turns the mix pink is most often titanium oxide or zinc oxide, which are both whitish in color. But Wu's materials are novel in that he's using more complex metals and exploring different particle shapes to boost the amount of electricity produced.

In a recent issue of the Journal of the American Chemical Society (JACS), he and his team report that they have made a new DSSC material using zinc stannate.

This is the first time that researchers have made a DSSC from anything other than a simple oxide. Wu and his colleagues chose zinc stannate because it belongs to a class of more complex oxides with tunable properties.

"This opens up new possibilities for how scientists may tailor the properties of DSSCs in the future," he said.

So why are DSSCs pink, and not blue like silicon-based solar cells?

Those traditional solar cells look blue because of an anti-reflective coating, he explained. The coating boosts absorption of green light, which is the strongest in the solar spectrum. Wu's materials don't have that anti-reflective coating.

Color determines the wavelength of light that a solar cell can capture, so adjusting the color lets scientists optimize particular properties in how the device will function. So far in the development of DSSCs, scientists have gotten the best performance from red ruthenium dye.

"If you want to achieve the best efficiency, you need to consider both the voltage you can achieve and the current you can achieve," Wu said. Voltage is the potential energy that the material could provide; current is the amount of charge it can transport.

"If you absorb a very broad range of wavelengths, that's going to sacrifice voltage. And if your absorption energy threshold is very high, you can achieve high voltage, but you'll sacrifice current. The idea is to find some balance."

Silicon-based solar cells have been around since the 1960s. Scientists have been working to develop DSSCs since the 1990s.

In DSSCs, dye molecules coat tiny metal oxide particles that are packed together into a thin film. The dye molecules capture light energy and release electrons, and the particles act like electrical wires to carry the electrons away to an electrical circuit.

But electrons can get lost when traveling between particles. That's why Wu is working on designs that incorporate tiny nano-wires that carry electrons directly to a circuit.

Last year, he and his team published a paper in the Journal of Physical Chemistry B describing DSSCs that contained particles and nano-wires of titanium oxide. That formulation achieved 8.6 percent efficiency -- roughly half of the 15 percent efficiency typical of commercially available silicon solar cells.

In the new JACS paper, they report that a formulation with zinc stannate particles -- but no nano-wires -- achieved 3.8 percent efficiency. Now they are working to combine the two strategies, by making nano-wires from zinc stannate and other oxides.

They are also exploring the possibility of using nano-trees -- nano-wires shaped like the branches of a tree.

"We asked ourselves, what structure is best for gathering light and also transporting materials -- a tree! The leaves provide a high surface area for capturing light, and the branches transport the nutrients to the roots," Wu said. "In our DSSC design, the dye-coated particles would provide the surface area, and the nano-trees would branch out in between them, to transport the electrons."

So dye-sensitized solar cells may contain tiny pink "trees" in the future, but other colors are possible, he said. Researchers are studying new dyes and dye combinations that may work better.

Wu's coauthors on the Journal of the American Chemical Society paper included postdoctoral researcher Bing Tan, doctoral student Yanguang Li, and undergraduate student Elizabeth Toman.

This research was partially funded by the American Chemical Society's Petroleum Research Fund.

| newswise
Further information:
http://www.osu.edu

More articles from Power and Electrical Engineering:

nachricht Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University

nachricht TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>