Scientists of the University of Luxembourg and of the Japanese electronics company TDK report progress in photovoltaic research: they have improved a component that will enable solar cells to use more energy of the sun and thus create a higher current.
The improvement concerns a conductive oxide film which now has more transparency in the infrared region. Similar attempts had been made before, but this is the first time that these films were prepared by a one-step process and, at the same time, stable in air.
“The films made at the University of Luxembourg have been exposed to air for one and half years and are still as conductive as when they were fresh prepared”, says Prof. Susanne Siebentritt, head of the laboratory for photovoltaics at the University of Luxembourg.
“It is a fantastic result, not only for solar cells, but also for a range of other technologies”, she adds. Collaborators of this study were Dr. Matěj Hála, research associate in the laboratory for photovoltaics and Shohei Fujii and Yukari Inoue, visiting scientists from TDK.
Transparent conductive oxides are used in any device combining electronics and light, like LEDs, solar cells, photodetectors or even touch screens. They have the particularity to combine the properties of metals, which are the best electrical conductors known, with those of oxides, which usually are transparent but not conductive, as for example glass. In solar cells the film has to be conductive because it constitutes the upper electrode. At the same time it has to be transparent in order for sunlight to reach the layer underneath, where the current is formed.
The oxides forming this film can be made conductive by deliberately adding impurities. Zinc oxide with aluminium added is a widely used example. In this case, the aluminium adds free electrons to the zinc oxide which are responsible for the conductivity. However, these free electrons also absorb infrared light. That means that less sun energy can pass through.
The team of the University of Luxembourg and TDK have modified the process used to make the film in order to make pure zinc oxide more conductive. “Our multidisciplinary team, benefitting from the exchange of knowledge across countries, had the idea to add an additional component - another gas plasma - in the so called sputter process. This makes the material conductive even without aluminium.” explains Prof. Siebentritt.
This method enables to have less but faster moving free electrons. “With this result, the conductivity is similar to the one with aluminium, but it enables a much better transparency in the infrared region as less free electrons cause also less absorption. That makes solar cells more efficient”, adds Dr. Matěj Hála. The findings are now published in the respected journal "Progress in Photovoltaics".
http://www.uni.lu - University of Luxembourg
Britta Schlüter | idw - Informationsdienst Wissenschaft
Decoding cement's shape promises greener concrete
08.12.2016 | Rice University
Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D
08.12.2016 | DOE/Brookhaven National Laboratory
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine