A step towards high-performance photovoltaics via three-component P3HT/PANI-graft-rGO nanocomposites

Abstract

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 (µ_h) and electron (µ_e) mobilities and also short circuit current density (J_sc) values. The highest µ_e (8.9 × 10^–3 cm²/V.s) and µ_h (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.

Graphical Abstract

Keywords:

• Polyaniline
• rGO
• P3HT
• crystallization
• solar cell

Conflicts of interest

There are no conflicts of interest to declare.