Monte Carlo Simulations of Charge Transport in 2D Organic Photovoltaics.
The effect of morphology on charge transport in organic photovoltaics is assessed using Monte Carlo. In isotopic two-phase morphologies, increasing the domain size from 6.3 to 18.3 nm improves the fill factor by 11.6%, a result of decreased tortuosity and relaxation of Coulombic barriers. Additionally, when small aggregates of electron acceptors are interdispersed into the electron donor phase, charged defects form in the system, reducing fill factors by 23.3% on average, compared with systems without aggregates. In contrast, systems with idealized connectivity show a 3.31% decrease in fill factor when domain size was increased from 4 to 64 nm. We attribute this to a decreased rate of exciton separation at donor-acceptor interfaces. Finally, we notice that the presence of Coulomb interactions increases device performance as devices become smaller. The results suggest that for commonly found isotropic morphologies the Coulomb interactions between charge carriers dominates exciton separation effects.
†University of Pittsburgh, Department of Chemistry, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States.
Adam G
AG
Gagorik
‡Carnegie Mellon University, Department of Chemistry, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
Jacob W
JW
Mohin
‡Carnegie Mellon University, Department of Chemistry, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
Tomasz
T
Kowalewski
†University of Pittsburgh, Department of Chemistry, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States.
Geoffrey R
GR
Hutchison
charge transfer; disordered transport; dynamic Monte Carlo; organic electronics; organic semiconductors; photovoltaics