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 A new tool for discovering nanoporous materials
23.05.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Did you know that packaging is becoming intelligent through flash systems?
23.05.2017 | Heraeus Noblelight GmbH

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>