Singlet exciton fission for solar cell applications: energy aspects of interchromophore coupling.
Singlet exciton fission, a process that converts one singlet exciton to a pair of triplet excitons, has the potential to enhance the efficiency of both bulk heterojunction and dye-sensitized solar cells and is understood in crystals but not well understood in molecules. Previous studies have identified promising building blocks for singlet fission in molecular systems, but little work has investigated how these individual chromophores should be combined to maximize triplet yield. We consider the effects of chemically connecting two chromophores to create a coupled chromophore pair and compute how various structural choices alter the thermodynamic and kinetic parameters likely to control singlet fission yield. We use density functional theory to compute the electron transfer matrix element and the thermodynamics of fission for several promising chromophore pairs and find a trade-off between the desire to maximize this element and the desire to keep the singlet fission process exoergic. We identify promising molecular systems for singlet fission and suggest future experiments.
Greyson
Eric C
EC
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
Stepp
Brian R
BR
Chen
Xudong
X
Schwerin
Andrew F
AF
Paci
Irina
I
Smith
Millicent B
MB
Akdag
Akin
A
Johnson
Justin C
JC
Nozik
Arthur J
AJ
Michl
Josef
J
Ratner
Mark A
MA