The films were synthesized at BGU by Prof. Yuval Golan and PhD student Anna Osherov of the Department of Materials Engineering and the Ilse Katz Institute for Nanoscale Science and Technology. The letter was published this week in Nature Physics.
One of the important factors limiting solar-cell efficiency is that incident photons generate only one electron–hole pair, irrespective of the photon energy. Any excess photon energy is lost as heat.
Carrier Multiplication (CM) has been thought to be enhanced significantly in nanocrystalline materials such as quantum dots, owing to their discrete energy levels and enhanced Coulomb interactions.
The BGU team demonstrated that contrary to this expectation, for a given photon energy, carrier multiplication occurs more efficiently in bulk PbS and PbSe films than in nanocrystalline films of the same materials.
"Films developed at BGU show CM, in which each incoming photon (tiny quantity of sunlight) creates more than one electron-hole pair," Golan explains. "This can potentially be used for making more efficient solar cells. The new physics behind this work are that while CM has been mostly demonstrated in nanocrystalline materials ("quantum dots"), we now show that CM can be obtained also in single crystal ('bulk') films of lead sulfide and lead selenide."
Notably, the films were prepared using chemical solution deposition, an attractive, inexpensive deposition technique for which the Golan group at BGU has received considerable recognition. The research was carried out as part of an international collaboration with counterparts in France and the Netherlands.
J.J.H. Pijpers, R. Ulbricht, K.J. Tielrooij, A. Osherov, Y. Golan, C. Delerue, G. Allan and M. Bonn, "Assessment of Carrier Multiplication efficiency in bulk PbSe and PbS", Nature Physics (2009) in press.
About Ben-Gurion University of the Negev and American Associates
Ben-Gurion University of the Negev is a world-renowned institute of research and higher learning with some 19,000 students on campuses in Beer-Sheva, Sede Boqer and Eilat in Israel's southern desert. It is a university with a conscience, where the highest academic standards are integrated with community involvement, committed to sustainable development of the Negev. Founded in 1972, American Associates, Ben-Gurion University of the Negev plays a vital role in helping the University fulfill its unique responsibility to develop the Negev, reach out to its local community and its Arab neighbors, and share its expertise with the world.
Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science
Artificial agent designs quantum experiments
19.01.2018 | Universität Innsbruck
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
19.01.2018 | Materials Sciences
19.01.2018 | Health and Medicine
19.01.2018 | Physics and Astronomy