Nav: Home

USC Viterbi researchers develop new class of optoelectronic materials

April 10, 2017

Semiconductors are used for myriad optoelectronic devices. However, as devices get smaller and smaller and more demanding, new materials are needed to ensure that devices work with greater efficiency. Now, researchers at the USC Viterbi School of Engineering have pioneered a new class of semiconductor materials that might enhance the functionality of optoelectronic devices and solar panels--perhaps even using one hundred times less material than the commonly used silicon.

Researchers at USC Viterbi, led by Jayakanth Ravichandran, an assistant professor in the Mork Family Department of Chemical Engineering and Material Sciences and including Shanyuan Niu, Huaixun Huyan, Yang Liu, Matthew Yeung, Kevin Ye, Louis Blankemeier, Thomas Orvis, Debarghya Sarkar, Assistant Professor of Electrical Engineering Rehan Kapadia, and David J. Singh, a professor of physics from University of Missouri, have developed a new class of materials that are superior in performance and have reduced toxicity. Their process, documented in "Bandgap Control via Structural and Chemical Tuning of Transition Metal Perovskite Chalcogenide," is published in Advanced Materials.

Ravichandran, the lead on this research, is a materials scientist, who has always been interested in understanding the flow of electrons and heat through materials, as well as the how electrons interact within materials. This deep knowledge of how material composition affects electron movement was critical to Ravichandran's and his colleagues' most recent innovation.

Computers and electronics have been getting better, but according to Jayakanth Ravichandran, the principal investigator of this study, "the performance of the most basic device--the transistors --are not getting better." There is a plateau in terms of performance, as noted by what is considered the "end of Moore's law." Similar to electronics, there is a lot of interest to develop high performance semiconductors for opto-electronics. The collaborative team of material scientists and electrical engineers wanted to develop new materials which could showcase the ideal optical and electrical properties for a variety of applications such as displays, light detectors and emitters, as well as solar cells.

The researchers developed a class of semiconductors called "transition metal perovskite chalcogenides." Currently, the most useful semiconductors don't hold enough carriers for a given volume of material (a property which is referred to as "density of states") but they transport electrons fast and thus are known to have high mobility. The real challenge for scientists has been to increase this density of states in materials, while maintaining high mobility. The proposed material is predicted to possess these conflicting properties.

As a first step to show its potential applications, the researchers studied its ability absorb and emit light. "There is a saying," says Ravichandran of the dialogue among those in the optics and photonics fields, "that a very good LED is also a very good solar cell." Since the materials Ravichandran and his colleagues developed absorb and emit light effectively, solar cells are a possible application.

Solar cells absorb light and convert it into electricity. However, solar panels are made of silicon, which comes from sand via a highly energy intensive extraction process. If solar cells could be made of a new, alternative semiconductor material such as the one created by the USC Viterbi researchers-- a material that could fit more electrons for a given volume (and reducing the thickness of the panels), solar cells could be more efficient--perhaps using one hundred times less material to generate the same amount of energy. This new material, if applied in the solar energy industry, could make solar energy less expensive.

While it is a long road to bring such a class of materials to market, the next step is to recreate this material in an ultra-thin film form to make solar cells and test their performance. "The key contribution of this work," says Ravichandran, "is our new synthesis method, which is a drastic improvement from earlier studies. Also, our demonstration of wide tunability in optical properties (especially band gap) is promising for developing new optoelectronic devices with tunable optical properties."
-end-
About the USC Viterbi School of Engineering

Engineering Studies began at the University of Southern California in 1905. Nearly a century later, in 2004, the Viterbi School of Engineering received a naming gift from alumnus Andrew J. Viterbi, inventor of the Viterbi algorithm, now the key to cellphone technology and numerous data applications. The school's guiding principles is Engineering +, a coined termed by current dean Yannis C. Yortsos, to use the power of engineering to address the world's greatest challenges. USC Viterbi is ranked among the top engineering programs in the world and enrolls more than 6,500 undergraduate and graduate students taught by 185 tenured and tenure-track faculty, with 73 endowed chairs and professorships.

University of Southern California

Related Solar Cells Articles:

Perovskite solar cells get an upgrade
Rice University materials scientists find inorganic compounds quench defects in perovskite-based solar cells and expand their tolerance of light, humidity and heat.
Can solar technology kill cancer cells?
Michigan State University scientists have revealed a new way to detect and attack cancer cells using technology traditionally reserved for solar power.
Solar cells with new interfaces
Scientists from NUST MISIS (Russia) and University of Rome Tor Vergata found out that a microscopic quantity of two-dimensional titanium carbide called MXene significantly improves collection of electrical charges in a perovskite solar cell, increasing the final efficiency above 20%.
Welcome indoors, solar cells
Swedish and Chinese scientists have developed organic solar cells optimised to convert ambient indoor light to electricity.
Mapping the energetic landscape of solar cells
A new spectroscopic method now makes it possible to measure and visualize the energetic landscape inside solar cells based on organic materials.
Solar energy becomes biofuel without solar cells
Soon we will be able to replace fossil fuels with a carbon-neutral product created from solar energy, carbon dioxide and water.
A good first step toward nontoxic solar cells
A team of engineers at Washington University in St. Louis has found what they believe is a more stable, less toxic semiconductor for solar applications, using a novel double mineral discovered through data analytics and quantum-mechanical calculations.
Organic solar cells will last 10 years in space
Scientists from the Skoltech Center for Energy Science and Technology, the Institute for Problems of Chemical Physics of RAS, and the Department of Chemistry of MSU presented solar cells based on conjugated polymers and fullerene derivatives, that demonstrated record-high radiation stability and withstand gamma radiation of >6,000 Gy raising hopes for their stable operation on the near-earth orbit during 10 years or even longer.
Next-gen solar cells spin in new direction
A nanomaterial made from phosphorus, known as phosphorene, is shaping up as a key ingredient for more sustainable and efficient next-generation perovskite solar cells.
Caffeine gives solar cells an energy boost
Scientists from the University of California, Los Angeles (UCLA) and Solargiga Energy in China have discovered that caffeine can help make a promising alternative to traditional solar cells more efficient at converting light to electricity.
More Solar Cells News and Solar Cells Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Accessing Better Health
Essential health care is a right, not a privilege ... or is it? This hour, TED speakers explore how we can give everyone access to a healthier way of life, despite who you are or where you live. Guests include physician Raj Panjabi, former NYC health commissioner Mary Bassett, researcher Michael Hendryx, and neuroscientist Rachel Wurzman.
Now Playing: Science for the People

#544 Prosperity Without Growth
The societies we live in are organised around growth, objects, and driving forward a constantly expanding economy as benchmarks of success and prosperity. But this growing consumption at all costs is at odds with our understanding of what our planet can support. How do we lower the environmental impact of economic activity? How do we redefine success and prosperity separate from GDP, which politicians and governments have focused on for decades? We speak with ecological economist Tim Jackson, Professor of Sustainable Development at the University of Surrey, Director of the Centre for the Understanding of Sustainable Propserity, and author of...
Now Playing: Radiolab

An Announcement from Radiolab