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Abstract
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For verifying the influence of donor–acceptor supramolecules on photovoltaic properties, different hybrids were
designed and used in organic solar cells. In this respect,
reduced graphene oxide (rGO) was functionalization with 2-thiophene acetic acid (rGO-f-TAA) and grafted with poly(3-dodecylthiophene) (rGO-g-PDDT) and poly(3-thiophene ethanol)
(rGO-g-PTEt) to manipulate orientation of poly(3-hexylthiophene) (P3HT) assemblies. Face-on, edge-on, and flat-on orientations were detected for assembled P3HTs on rGO and its
functionalized and grafted derivatives, respectively. Alteration
of P3HT orientation from face-on to flat-on enhanced current
density (Jsc), fill factor (FF), and power conversion efficiency
(PCE) and thus Jsc57.11 mA cm
22
,FF547%, and PCE52.14%
were acquired. By adding phenyl-C71-butyric acid methyl ester
(PC71BM) to active layers composed of pre-designed P3HT/
rGO, P3HT/rGO-f-TAA, P3HT/rGO-g-PDDT, and P3HT/rGO-gPTEt hybrids, photovoltaic characteristics further improved,
demonstrating that supramolecules appropriately mediated in
P3HT:PC71BM solar cells. Phase separation was more intensified
in best-performing photovoltaic systems. Larger P3HT crystals
assembled onto grafted rGOs (95–143 nm) may have acted as
convenient templates for the larger and more intensified phase
separation in P3HT:PCBM films. The best performances were
reached for P3HT:P3HT/rGO-g-PDDT:PCBM (Jsc59.45 mA cm
22
,
FF554%, and PCE53.16%) and P3HT:P3HT/rGO-g-PTEt:PCBM
(Jsc59.32 mA cm
22
,FF553%, and PCE53.11%) photovoltaic
systems.
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