The Physics of Small Molecule Acceptors for Efficient and table Bulk Heterojunction Solar Cells​

Recent Review Paper in Advanced Energy Materials by Post Doc Nicola Gasparini and PI Derya Baran


Organic bulk heterojunction solar cells based on small molecule acceptors
have recently seen a rapid rise in the power conversion efficiency with values
exceeding 13%. This impressive achievement has been obtained by simulta-
neous reduction of voltage and charge recombination losses within this class
of materials as compared to fullerene-based solar cells. In this contribution,
the authors review the current understanding of the relevant photophysical
processes in highly efficient nonfullerene acceptor (NFA) small molecules.
Charge generation, recombination, and charge transport is discussed in
comparison to fullerene-based composites. Finally, the authors review the
superior light and thermal stability of nonfullerene small molecule acceptor
based solar cells, and highlight the importance of NFA-based composites
that enable devices without early performance loss, thus resembling so-called
burn-in free devices.​