posted on 2021-09-24, 20:29authored byMathieu Mainville, Ryan Ambrose, Daniel Fillion, Ian G. Hill, Mario Leclerc, Paul A. Johnson
Organic
photovoltaics based on non-fullerene acceptors (NFAs) have
gained enormous interest over the past few years. Recent fused-ring
systems such as ITIC, IDT, and Y families are particularly promising
for several photovoltaic devices. Since the complexity of these molecular
designs has grown substantially, the development of materials with
specific properties has become a laborious process. Therefore, many
studies employ computational modeling, in particular density functional
theory (DFT), to anticipate material electronic properties. Such approaches
provide useful information about proposed organic semiconductors,
such as optical absorption, frontier orbital energy levels, and molecular
geometries. However, the accuracy of the common methods for recent
organic semiconductors has not been explored. Thus, we herein evaluate
a series of DFT functionals and Hartree–Fock (HF) theory for
a collection of 14 common NFAs. Computational results are compared
with physical properties from cyclic voltammetry, photoelectron spectroscopy,
UV–visible absorption spectroscopy, and ellipsometry. By applying
empirical corrections from linear fits, mean absolute errors between
theoretical and experimental results below 0.05 eV could be achieved
for the highest occupied molecular orbital (HOMO) and lowest unoccupied
molecular orbital (LUMO) energies as well as maximum absorption energies.
Moreover, all of these experimental results for these 14 common NFAs
could be useful for future device optimization.