Graphene nanoflakes triple solar panel efficiency
Fei Yu, a University of Cincinnati doctoral student in materials engineering, has experimented with adding a small fraction of graphene nanoflakes to polymer-blend bulk-heterojunction (BHJ) solar cells to improve performance and lower costs of solar energy. Yu’s research found that efficiency increased threefold by adding graphene, because the material was helping to rapidly transport charges to achieve higher photocurrent.
"There has been a lot of study on how to make plastic solar cells more efficient, so they can take the place of silicon solar cells in the future,” explained Yu. “They can be made into thinner, lighter and more flexible panels. However, they’re currently not as efficient as silicon solar cells, so we’re examining how to increase that efficiency.”
“Because graphene is pure carbon, its charge conductivity is very high. We want to maximize the energy being absorbed by the solar cell, so we are increasing the ratio of the donor to acceptor and we’re using a very low fraction of graphene to achieve that.”
“The increased performance, although well below the highest efficiency achieved in organic photovoltaic (OPV) devices, is nevertheless significant in indicating that pristine graphene can be used as a charge transporter.”
Future research will focus on device physics, film morphology and how to control and optimize these randomly distributed graphene nanoflakes by a variety of methods to achieve better performance.
Yu presented his findings on boosting the power conversion efficiency of polymer solar cells on March 3, at the American Physical Society Meeting in Denver, USA.
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