Tailoring Nanoscale Morphology of Polymer:Fullerene Blends Using Electrostatic Field

To
tailor the nanomorphology in polymer/fullerene blends, we study the
effect of electrostatic field (E-field) on the solidification of poly­(3-hexylthiophene-2,
5-diyl) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PC60BM) bulk heterojunction (BHJ). In addition to control; wet
P3HT:PC60BM thin films were exposed to E-field of Van de
Graaff (VDG) generator at three different directionshorizontal
(H), tilted (T), and vertical (V)relative to the plane of
the substrate. Surface and bulk characterizations of the field-treated
BHJs affirmed that fullerene molecules can easily penetrate the spaghetti-like
P3HT and move up and down following the E-field. Using E-field treatment,
we achieved favorable morphologies with efficient charge separation,
transport, and collection. We improve; (1) the hole mobility values
up to 19.4 × 10–4 ± 1.6 × 10–4 cm2 V–1 s–1 and (2) the power conversion efficiency (PCE) of conventional and
inverted OPVs up to 2.58 ± 0.02% and 4.1 ± 0.40%, respectively.
This E-field approach can serve as a new morphology-tuning technique,
which is generally applicable to other polymer–fullerene systems.