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Abstract
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Polyaniline-grafted reduced graphene oxide (PANI-graft-rGO) was synthesized by in situ oxidative
polymerization of aniline using amine-terminated rGO (rGO-NH2) as an initiator. Nanosheets were
applied as templates for crystallization of regioregular poly(3-hexylthiophene) (P3HT) chains. The
resulting nano-hybrids entitled supra(rGO-NH2/P3HT) and supra(PANI-graft-rGO/P3HT) were utilized
in the active layers of P3HT:phenyl-C71-butyric acid methyl ester (PC71BM) solar cells to improve the
photovoltaic characteristics up to (6.79 mA/cm2, 43%, and 0.65 V) and (13.21 mA/cm2, 64%, and
0.67 V), leading to the efficiencies of 1.90% and 5.66%, respectively. In similar conditions and only
via replacing the rGO-NH2 with PANI-graft-rGO, the photovoltaic features were elevated. It could be
assigned to the impact of PANI grafts in facilitating th[e surface crystallization of P3HT host chains
and thereby in well-arranging the active layer constituents. The PANI mediators may act as both
acceptors (accepting the electrons from rGO) and donors (donating the electrons to P3HT crystals)
in configuration of supra(PANI-graft-rGO/P3HT) nano-hybrids, thus made the supra(PANI-graft-rGO/
P3HT) nanostructures the appropriate candidates in manipulation of cell factors. This phenomenon
was comprehended from the escalation in contents of hole (mh) and electron (me) mobilities and also
short circuit current density (Jsc) values. The highest me (8.9 10–3 cm2/V.s) and mh (4.5 10–3 cm2/
V.s) were acquired for electron-only (Al/supra(PANI-graft-rGO/P3HT):P3HT:PC71BM/Al) and hole-only
(indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/
supra(PANI-graft-rGO/P3HT):P3HT:PC71BM/Pd) devices. In similar conditions, the charge mobilities
were lower in rGO-NH2 based systems either with PC71BM molecules or without them.
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