Nonlinear Waves Seminar: Sean Shaheen

Modeling of Organic Photovoltaics: Charge Transport, Charge Transfer Kinetics, and Exciton Dynamics

Sean Shaheen

Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder

Date and time: 

Tuesday, April 29, 2014 - 4:30pm

Location: 

ECOT 226

Abstract: 

Organic Photovoltaic (OPV) devices, which utilize polymeric or molecular materials as the photoactive material, rely on a complex interplay of exciton dynamics, charge transfer, and charge transport to harness energy from sunlight.  Current best devices have solar power conversion efficiencies of 12%; however, to keep pace with competitive technologies, OPV must strive for efficiencies approaching 20%.  In this talk, I will discuss modeling and simulation of several aspects of the device operation.  First, I will describe Monte Carlo simulations of charge transport on energetically disordered 3D lattices, as an approach to understand the carrier mobility and influence of charge trapping in polymeric materials.  Second, I will address more fundamental charge transfer issues and give qualitative results on how reduction of molecular reorganization energy provides a pathway to higher efficiencies using simple kinetic models.  Lastly, I will discuss fundamental exciton dynamics in these molecular systems and how energy transfer schemes, in particular coherent "energy pooling", may be used to reach higher efficiencies.