This physical effect could pave the way for cheap, high-output solar cells. The findings are to be published in scientific journal Nano Letters this week.
Solar cells provide great opportunities for future large-scale electricity generation. However, there are currently significant limitations, such as the relatively low output of most solar cells (typically fifteen percent) and high manufacturing costs.
One possible improvement could derive from a new type of solar cell made of semiconducting nanocrystals (crystals with dimensions in the nanometre size range). In conventional solar cells, one photon (light particle) can release precisely one electron. The creation of these free electrons ensures that the solar cell works and can provide power. The more electrons released, the higher the output of the solar cell.
In some semiconducting nanocrystals, however, one photon can release two or three electrons, hence the term avalanche effect. This could theoretically lead to a maximum output of 44 percent in a solar cell comprising the correct semiconducting nanocrystals. Moreover, these solar cells can be manufactured relatively cheaply.
The avalanche effect was first measured by researchers at the Los Alamos National Laboratories in 2004. Since then, the scientific world has raised doubts about the value of these measurements. Does the avalanche effect really exist or not?
Within the Joint Solar Programme TU Delft’s Prof. Laurens Siebbeles has now demonstrated that the avalanche effect does indeed occur in lead selenide (PbSe) nanocrystals. It has been established, however, that the effect in this material is smaller than previously assumed. Siebbeles’ results are more reliable than those of other scientists thanks to more careful and more detailed measurement using ultra-fast laser methods.
Siebbeles believes that this research paves the way for further unravelling the secrets of the avalanche effect.
Maarten van der Sanden | alfa
Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz
Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
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