Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New material approach should increase solar cell efficiency

24.04.2013
“When designing next generation solar energy conversion systems, we must first develop ways to more efficiently utilize the solar spectrum,” explained Lane Martin, whose research group has done just that.

“This is a fundamentally new way of approaching these matters,” said Martin, who is an assistant professor of materials science and engineering (MatSE) at Illinois. “From these materials we can imagine carbon-neutral energy production of clean-burning fuels, waste water purification and remediation, and much more.”


The correlated electron metal SrRuO3 exhibits strong visible slight absorption. Overlaid here on the AM1.5G solar spectrum, it can be seen that SrRuO3 absorbs more than 75 times more light than TiO2. The structural, chemical, and electronic compatibility of TiO2 and SrRuO3 further enables the fabrication of heterojunctions with exciting photovoltaic and photocatalytic response driven by hot-carrier injection.

Martin’s research group brought together aspects of condensed matter physics, semiconductor device engineering, and photochemistry to develop a new form of high-performance solar photocatalyst based on the combination of the TiO2 (titanium dioxide) and other “metallic” oxides that greatly enhance the visible light absorption and promote more efficient utilization of the solar spectrum for energy applications. Their paper, “Strong Visible-Light Absorption and Hot-Carrier Injection in TiO2/SrRuO3 Heterostructures,” appears in the journal Advanced Energy Materials.

According to Martin, the primary feature limiting the performance of oxide-based photovoltaic and/or photocatalytic systems has traditionally been the poor absorption of visible light in these often wide band gap materials. One candidate oxide material for such applications is anatase TiO2, which is arguably the most widely-studied photocatalyst due to its chemical stability, non-toxicity, low-cost, and excellent band alignment to several oxidation-reduction reactions. As the backbone of dye-sensitized solar cells, however, the presence of a light-absorbing dye accounts for a large band gap which limits efficient usage of all but the UV portion of sunlight.

“We observed that the unusual electronic structure of SrRuO3 is also responsible for unexpected optical properties including high absorption across the visible spectrum and low reflection compared to traditional metals,” stated Sungki Lee, the paper’s first author. “By coupling this material to TiO2 we demonstrate enhanced visible light absorption and large photocatalytic activities.”

“SrRuO3 is a correlated electron oxide which is known to possess metallic-like temperature dependence of its resistivity and itinerant ferromagnetism and for its widespread utility as a conducting electrode in oxide heterostructures,” Lee added. Referring to this material as a “metal,” however, is likely inappropriate as the electronic structure and properties are derived from a combination of complex electronic density of states, electron correlations, and more.

Using a process called photo-excited hot-carrier injection from the SrRuO3 to the TiO2, the researchers created new heterostructures whose novel optical properties and the resulting high photoelectrochemical performance provide an interesting new approach that could advance the field of photocatalysis and further broaden the potential applications of other metallic oxides.

This work provides an exciting new approach to the challenge of designing visible-light photosensitive materials and has resulted in a provisional patent application. The work was primarily supported by the ongoing International Institute for Carbon Neutral Energy Research (I2CNER) program, a partnership between Kyushu University in Japan and the University of Illinois.

“The I2CNER project brings together some of the leading energy researchers from around the globe,” explained I2CNER Director Petros Sofronis, who is also a professor in the Department of Mechanical Science and Engineering at Illinois. “Results from Dr. Martin’s research group and others demonstrate that I2CNER is not only an experiment on international collaboration. It is a concerted institutionalized effort to pursue green innovation and reduced CO2 emissions, as well as to advance fundamental science and develop science-based technological solutions for the reorganization of sustainable and environmentally friendly society.”

Contact:
Lane Martin, Department of Materials Science and Engineering, 217/244-9162

Petros Sofronis, director, International Institute for Carbon Neutral Energy Research, 217/333-2636.

Writer: Rick Kubetz, Engineering Communications Office, 217/244-7716

Lane Martin | EurekAlert!
Further information:
http://www.illinois.edu

More articles from Materials Sciences:

nachricht Gelatine instead of forearm
19.04.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Computers create recipe for two new magnetic materials
18.04.2017 | Duke University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>