Polymorphism of Crystalline Molecular Donors for Solution-Processed Organic Photovoltaics.
Using ab initio calculations and classical molecular dynamics simulations coupled to complementary experimental characterization, four molecular semiconductors were investigated in vacuum, solution, and crystalline form. Independently, the molecules can be described as nearly isostructural, yet in crystalline form, two distinct crystal systems are observed with characteristic molecular geometries. The minor structural variations provide a platform to investigate the subtlety of simple substitutions, with particular focus on polymorphism and rotational isomerism. Resolved crystal structures offer an exact description of intermolecular ordering in the solid state. This enables evaluation of molecular binding energy in various crystallographic configurations to fully rationalize observed crystal packing on a basis of first-principle calculations of intermolecular interactions.
Thomas S
TS
van der Poll
‡Theoretical Division, Center for Nonlinear Studies and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, T-12, MS B268, Los Alamos, New Mexico 87545, United States.
Andriy
A
Zhugayevych
‡Theoretical Division, Center for Nonlinear Studies and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, T-12, MS B268, Los Alamos, New Mexico 87545, United States.
Eli
E
Chertkov
Ronald C
RC
Bakus
Jessica E
JE
Coughlin
§Advanced Light Source, Lawrence Berkeley National Laboratory, 6 Cyclotron Road, Berkeley, California 94720, United States.
Simon J
SJ
Teat
Guillermo C
GC
Bazan
‡Theoretical Division, Center for Nonlinear Studies and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, T-12, MS B268, Los Alamos, New Mexico 87545, United States.
Sergei
S
Tretiak
density functional theory; molecular mechanics; organic semiconductors; polymorphism; single crystals