Photovoltaics are slowly making their way into a variety of project typologies. And, now, with new developments from chemist Xiaoyang Zhu at the University of Texas, solar cells can upgrade from their solar efficiency current limit of 30% to more than 60%. To increase the cells efficiency, Zhu studied capturing hot electrons (energy that is too high to be turned into usable electricity which then escapes) with quantum dots.
Using nanocrystals, or quantum dots, which slow the cooling of the hot electrons, Zhu was able to remove the electrons with a titanium dioxide conductor. By removing the electrons quickly, their energy can be harvested for power.
Zhu’s discovery is a step in the right direction, yet it is just one part of a series of crucial steps to reach the ultimate solar cell. Currently Zhu is working on finding the solution for the next problem – that hot electrons also lose their energy as they travel along the wire.
“If we take out electrons from the solar cell that are this fast, or hot, we also lose energy in the wire as heat,” says Zhu. “Our next goal is to adjust the chemistry at the interface to the conducting wire so that we can minimize this additional energy loss. We want to capture most of the energy of sunlight. That’s the ultimate solar cell.”