Metal oxides hold the key to cheap, green energyApril 19, 2012
"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."
Related Metal Oxides Current Events and Metal Oxides News Articles
Laser-burned graphene gains metallic powers
Rice University chemists who developed a unique form of graphene have found a way to embed metallic nanoparticles that turn the material into a useful catalyst for fuel cells and other applications.
Rice University finding could lead to cheap, efficient metal-based solar cells
New research from Rice University could make it easier for engineers to harness the power of light-capturing nanomaterials to boost the efficiency and reduce the costs of photovoltaic solar cells.
Two-dimensional dirac materials: Structure, properties, and rarity
Graphene, a two-dimensional (2D) honeycomb sheet composed of carbon atoms, has attracted intense interests worldwide because of its outstanding properties and promising prospects in both basic and applied science.
Researchers increase energy density of lithium storage materials
The lithium ion battery currently is the most widespread battery technology. It is indispensable for devices, such as laptops, mobile phones or cameras.
New flexible films for touch screen applications achieve longer lasting display
Today, touch screens are everywhere, from smart phones and tablets, to computer monitors, to interactive digital signage and displays.
Reducing greenhouse gas emissions with a more effective carbon capture method
Trapping carbon dioxide (CO2) emissions from power plants and various industries could play a significant role in reducing greenhouse gas emissions in the future.
Worms lead way to test nanoparticle toxicity
The lowly roundworm is the star of an ambitious Rice University project to measure the toxicity of nanoparticles.
Waterloo chemist one step closer to a new generation of electric car battery
An ultra-thin nanomaterial is at the heart of a major breakthrough by Waterloo scientists who are in a global race to invent a cheaper, lighter and more powerful rechargeable battery for electric vehicles.
Atmospheric carbon dioxide used for energy storage products
Chemists and engineers at Oregon State University have discovered a fascinating new way to take some of the atmospheric carbon dioxide that's causing the greenhouse effect and use it to make an advanced, high-value material for use in energy storage products.
Good vibrations give electrons excitations that rock an insulator to go metallic
For more than 50 years, scientists have debated what turns particular oxide insulators, in which electrons barely move, into metals, in which electrons flow freely.
More Metal Oxides Current Events and Metal Oxides News Articles