TY - JOUR
T1 - Yield of exciton dissociation in a donor-acceptor photovoltaic junction
AU - Li, Guangqi
AU - Nitzan, Abraham
AU - Ratner, Mark A.
PY - 2012/11/7
Y1 - 2012/11/7
N2 - A simple model is constructed to describe dissociation of charge transfer excitons in bulk heterojunction solar cells, and its dependence on the physical parameters of the system. In bulk heterojunction organic photovoltaics (OPVs), exciton dissociation occurs almost exclusively at the interface between the donor and acceptor, following one-electron initial excitation from the HOMO to the LUMO levels of the donor, and charge transfer to the acceptor to make a charge-transfer exciton. After exciton breakup, and neglecting the trapping of individual carriers, the electron may undergo two processes for decay: one process involves the electron and/or hole leaving the interface, and migrating to the electrode. This is treated here as the electron moving on a set of acceptor sites. The second loss process is radiationless decay following recombination of the acceptor electron with the donor cation; this is treated by adding a relaxation term. These two processes compete with one another. We model both the exciton breakup and the subsequent electron motion. Results depend on tunneling amplitude, energetics, disorder, Coulomb barriers, and energy level matchups, particularly the so-called LUMO-LUMO offset.
AB - A simple model is constructed to describe dissociation of charge transfer excitons in bulk heterojunction solar cells, and its dependence on the physical parameters of the system. In bulk heterojunction organic photovoltaics (OPVs), exciton dissociation occurs almost exclusively at the interface between the donor and acceptor, following one-electron initial excitation from the HOMO to the LUMO levels of the donor, and charge transfer to the acceptor to make a charge-transfer exciton. After exciton breakup, and neglecting the trapping of individual carriers, the electron may undergo two processes for decay: one process involves the electron and/or hole leaving the interface, and migrating to the electrode. This is treated here as the electron moving on a set of acceptor sites. The second loss process is radiationless decay following recombination of the acceptor electron with the donor cation; this is treated by adding a relaxation term. These two processes compete with one another. We model both the exciton breakup and the subsequent electron motion. Results depend on tunneling amplitude, energetics, disorder, Coulomb barriers, and energy level matchups, particularly the so-called LUMO-LUMO offset.
UR - http://www.scopus.com/inward/record.url?scp=84867482241&partnerID=8YFLogxK
U2 - 10.1039/c2cp41532a
DO - 10.1039/c2cp41532a
M3 - מאמר
AN - SCOPUS:84867482241
VL - 14
SP - 14270
EP - 14276
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 41
ER -