Active layer morphology is of vital importance for the
photovoltaic
performance of organic solar cells (OSCs). As fullerene derivatives
and nonfullerene acceptors are highly complementary in many aspects,
fullerene derivatives as a third component in nonfullerene OSCs could
tune the blend morphology and improve the power conversion efficiency
(PCE). Relative to PCBM, the indene-C60 bisadduct (IC60BA) as the third component in nonfullerene binary OSCs has not been
extensively studied. Here, the fullerene derivative IC60BA is introduced into the PTZ1:IDIC blend system to finely tune the
active layer morphology. Although the addition of IC60BA
reduced the film absorption in the visible region and weakened the
crystallinity, the more symmetric charge transport property, smaller
domain size, and higher domain purity led to improved photovoltaic
performance. This study indicates that IC60BA is a promising
candidate to finely tune the morphology for achieving highly efficient
OSCs.