Conventional solar cells generate one electron for each absorbed photon, wasting a photon’s excess energy above the bandgap. Exciton fission in organic molecules splits a high-energy excited state into a pair of low-energy ones. In solar cells, it promises to double the photocurrent for the blue/green solar spectrum and overcome the fundamental photovoltaic efficiency limit. The talk will describe a photovoltaic cell based on exciton fission, which for the first time produced more than one electron per photon in the visible spectrum. Also, the fundamental mechanism governing exciton fission will be discussed.
The talk will explore the potential of integrating materials with different size dimensions to achieve unprecedented optoelectronic functions. As an example, I will demonstrate electrical control of energy transfer from semiconductor nanocrystals to graphene, which can be exploited as a nano-sized light switch for photonic communications.
Jiye Lee is currently a postdoctoral fellow in the Molecular Foundry at Lawrence Berkeley National Laboratory. She received her PhD in electrical engineering at Massachusetts Institute of Technology in 2013, working on exciton fission in organic solar cells with Prof. Marc Baldo. Her PhD thesis won the Microsystems Technology Laboratories Doctoral Dissertation Seminar at MIT. She obtained her B.S. in electrical engineering from Korea Advanced Institute of Science and Technology in 2006. Her research interests are optoelectronics and electronics based on nanomaterials, including organic molecules, nanocrystals, and 2D semiconductors.