Nav: Home

Metal oxides hold the key to cheap, green energy

April 18, 2012

BINGHAMTON, NY - Harnessing the energy of sunlight can be as simple as tuning the optical and electronic properties of metal oxides at the atomic level by making an artificial crystal or super-lattice 'sandwich' says a Binghamton University researcher in a new study published in the journal Physical Review B.

"Metal oxides are cheap, abundant and 'green,'" said Louis Piper, assistant professor of physics at Binghamton University. "And as the study proved, quite versatile. With the right touch, metal oxides can be tailored to meet all sorts of needs, which is good news for technological applications, specifically in energy generation and flat screen displays."

Here's how it works: semiconductors are an important class of materials in between metals and insulators. They are defined by the size of their band gap, which represents the energy required to excite an electron from the occupied shell to an unoccupied shell where it can conduct electricity. Visible light covers a range of 1 (infrared) to 3 (ultraviolet) electron volts. For transparent conductors, a large band gap is required, whereas for artificial photosynthesis, a band gap corresponding to green light is needed. Metal oxides provide a means of tailoring the band gap.

But while metal oxides are very good at electron conduction, they are very poor "hole" conductors. Holes refer to absence of electrons, and can conduct positive charge. To maximize their technologically potential, especially for artificial photosynthesis and invisible electronics, hole conducting metal oxides are required.

Knowing this, Piper has begun studying layered metal oxides systems, which can be combined to selectively 'dope' (replace a small number of one type of atom in the material), or 'tune' (control the size of the band gap). Recent work revealed that a super-lattice of two hole-conducting copper oxides could cover the entire solar spectrum. The goal is to improve the performance whilst using environmentally benign and cheap metal alternatives.

For instance, indium oxide is one of the most widely used oxides used in the production of coatings for flat screen displays and solar cells. It can conduct electrons really well and is transparent. But it is also rare and very expensive. Piper's current research is aimed towards using much cheaper tin oxide layers to get electron and hole conduction with optical transparency.

But according to Piper, his research shows that one glove will not fit all purposes.

"It's going to be a case of some serious detective work," said Piper. "We're working in a world where physics and chemistry overlap. And we've reached the theoretical limit of our calculations and fundamental processes. Now we need to audit those calculations and see where we're missing things. I believe we will find those missing pieces by playing around with metal oxides."

By reinforcing metal oxides' 'good bits' and downplaying the rough spots, Piper is convinced that the development of new and exciting types of metal oxides that can be tailored for specific applications are well within our reach.

"We're talking battery storage, fuel cells, touch screen technology and all types of computer switches," said Piper. "We're in the middle of a very important gold rush and its very exciting to be part of that race to strike it rich. But first we have to figure out what we don't know before we can figure out what we do. One thing's for sure: metal oxides hold the key. And I believe that we at Binghamton University can contribute to these efforts by doing good science and taking a morally conscious approach."

-end-



Binghamton University

Related Energy Articles:

Wave energy researchers dive deep to advance clean energy source
One of the biggest untapped clean energy sources on the planet -- wave energy -- could one day power millions of homes across the US.
A new energy source within the cells
Scientists at the Centre for Genomic Regulation in Barcelona, Spain, find evidence of a new energy source within cell nucleus.
MIT Energy Initiative welcomes Exelon as member for clean energy research
MIT Energy Initiative announces that national energy provider Exelon joins MITEI as a member to focus research support through MITEI's Low-Carbon Energy Centers.
Clean energy from water
Fuel cells generate electrical energy through a chemical reaction of hydrogen and oxygen.
Determinant factors for energy consumption and perception of energy conservation clarified
Change in lifestyle is a key component to realizing a low-carbon society.
Lactate for brain energy
Nerve cells cover their high energy demand with glucose and lactate.
Evidence shows low energy sweeteners help reduce energy intake and body weight
Use of low energy sweeteners (LES) in place of sugar, in children and adults, leads to reduced calorie intake and body weight - and possibly also when comparing LES beverages to water -- according to a review led by researchers at the University of Bristol published in the International Journal of Obesity today.
ASU professor honored for work on energy and social aspects of energy policy
Martin 'Mike' Pasqualetti, an Arizona State University professor and an expert on energy and social components of energy development, will be awarded 2015 Alexander and Ilse Melamid Memorial Medal by the American Geographical Society.
Stanford's Global Climate and Energy Project awards $9.3 million for energy research
GCEP has awarded scientists at Stanford and four other universities funding to develop a suite of promising energy technologies.
Energy efficiency upgrades ease strain of high energy bills in low-income families
Low-income families bear the brunt of high-energy costs and poor thermal comfort from poorly maintained apartment buildings.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: Radiolab

Oliver Sipple
One morning, Oliver Sipple went out for a walk. A couple hours later, to his own surprise, he saved the life of the President of the United States. But in the days that followed, Sipple's split-second act of heroism turned into a rationale for making his personal life into political opportunity. What happens next makes us wonder what a moment, or a movement, or a whole society can demand of one person. And how much is too much?
Now Playing: TED Radio Hour

Future Consequences
From data collection to gene editing to AI, what we once considered science fiction is now becoming reality. This hour, TED speakers explore the future consequences of our present actions. Guests include designer Anab Jain, futurist Juan Enriquez, biologist Paul Knoepfler, and neuroscientist and philosopher Sam Harris.